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Leopoldo Zelante - One of the best experts on this subject based on the ideXlab platform.
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Large rearrangements detected by MLPA, point mutations, and survey of the frequency of mutations within the SLC3A1 and SLC7A9 genes in a cohort of 172 cystinuric Italian patients.
Molecular genetics and metabolism, 2010Co-Authors: Luigi Bisceglia, Lucia Fischetti, Patrizia De Bonis, Orazio Palumbo, Bartolomeo Augello, Pietro Stanziale, Massimo Carella, Leopoldo ZelanteAbstract:Abstract Cystinuria is a rare inherited disorder characterized by defective renal reabsorption of cystine and the dibasic amino acids. SLC3A1 and SLC7A9 have been identified as responsible genes. The large majority of the more than 200 mutations so far identified in the two genes are point mutations, while only few alleles carrying gross genomic alterations have been reported. We screened 39 cystinuric patients for large rearrangements, by two home-made multiplex ligation-dependent probe amplification (MLPA) assays. MLPA analysis led to the identification of 6 different alleles in SLC3A1 and 2 in SLC7A9 accounting for a total of 25 copy number changes, 11 in SLC3A1 and 14 in SLC7A9 . Three large rearrangements in SLC3A1 , deletion of exons 2–4 (E2_E4del), deletion of exons 5–6 (E5_E6del) and duplication of exons 8–9 (E8_E9dup) are novel. A complete SLC7A9 gene deletion was found in three patients. In addition, we report the identification of three novel point mutations in SLC7A9 (p.G105E, p.R250K, c.1416_1417insAC), the frequency and the occurrence of Cystinuria mutations in a cohort of 172 Italian patients. In conclusion, we developed a reliable and robust MLPA analytic method for SLC3A1 and SLC7A9 genes that represents an optimal complement to DNA sequence analysis in patients with Cystinuria, enabling the screening for deletions and duplications.
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Comparison between SLC3A1 and SLC7A9 Cystinuria Patients and Carriers: A Need for a New Classification
Journal of the American Society of Nephrology : JASN, 2002Co-Authors: Luca Dello Strologo, Elon Pras, Luigi Bisceglia, Ercole Beccia, Michele Gallucci, Alberto Ponzone, C. Pontesilli, Vittorino Ricci-barbini, Luisa De Sanctis, Leopoldo ZelanteAbstract:Recent developments in the genetics and physiology of Cystinuria do not support the traditional classification, which is based on the excretion of cystine and dibasic amino acids in obligate heterozygotes. Mutations of only two genes (SLC3A1 and SLC7A9), identified by the International Cystinuria Consortium (ICC), have been found to be responsible for all three types of the disease. The ICC set up a multinational database and collected genetic and clinical data from 224 patients affected by Cystinuria, 125 with full genotype definition. Amino acid urinary excretion patterns of 189 heterozygotes with genetic definition and of 83 healthy controls were also included. All SLC3A1 carriers and 14% of SLC7A9 carriers showed a normal amino acid urinary pattern (i.e., type I phenotype). The rest of the SLC7A9 carriers showed phenotype non-I (type III, 80.5%; type II, 5.5%). This makes the traditional classification imprecise. A new classification is needed: type A, due to two mutations of SLC3A1 (rBAT) on chromosome 2 (45.2% in our database); type B, due to two mutations of SLC7A9 on chromosome 19 (53.2% in this series); and a possible third type, AB (1.6%), with one mutation on each of the above-mentioned genes. Clinical data show that Cystinuria is more severe in males than in females. The two types of Cystinuria (A and B) had a similar outcome in this retrospective study, but the effect of the treatment could not be analyzed. Stone events do not correlate with amino acid urinary excretion. Renal function was clearly impaired in 17% of the patients.
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Functional analysis of mutations in SLC7A9, and genotype-phenotype correlation in non-Type I Cystinuria.
Human molecular genetics, 2001Co-Authors: Mariona Font, Elon Pras, Virginia Nunes, Luigi Bisceglia, Xavier Estivill, Eliahu Golomb, Lídia Feliubadaló, Yitshak Kreiss, Adamo Pio D'adamo, Leopoldo ZelanteAbstract:Cystinuria (OMIM 220100) is a common recessive disorder of renal reabsorption of cystine and dibasic amino acids that results in nephrolithiasis of cystine. Mutations in SLC3A1, which encodes rBAT, cause Type I Cystinuria, and mutations in SLC7A9, which encodes a putative subunit of rBAT (b(o,+)AT), cause non-Type I Cystinuria. Here we describe the genomic structure of SLC7A9 (13 exons) and 28 new mutations in this gene that, together with the seven previously reported, explain 79% of the alleles in 61 non-Type I Cystinuria patients. These data demonstrate that SLC7A9 is the main non-Type I Cystinuria gene. Mutations G105R, V170M, A182T and R333W are the most frequent SLC7A9 missense mutations found. Among heterozygotes carrying these mutations, A182T heterozygotes showed the lowest urinary excretion values of cystine and dibasic amino acids. Functional analysis of mutation A182T after co-expression with rBAT in HeLa cells revealed significant residual transport activity. In contrast, mutations G105R, V170M and R333W are associated to a complete or almost complete loss of transport activity, leading to a more severe urinary phenotype in heterozygotes. SLC7A9 mutations located in the putative transmembrane domains of b(o,+)AT and affecting conserved amino acid residues with a small side chain generate a severe phenotype, while mutations in non-conserved residues give rise to a mild phenotype. These data provide the first genotype-phenotype correlation in non-Type I Cystinuria, and show that a mild urinary phenotype in heterozygotes may associate with mutations with significant residual transport activity.
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localization by linkage analysis of the Cystinuria type iii gene to chromosome 19q13 1
American Journal of Human Genetics, 1997Co-Authors: Luigi Bisceglia, Maria Julia Calonge, Xavier Testar, Michele Gallucci, Alberto Ponzone, Lídia Feliubadaló, Antonio Totaro, Salvatore Melchionda, Judith Garcia, Leopoldo ZelanteAbstract:Cystinuria is an autosomal recessive aminoaciduria in which three urinary phenotypes (I, II, and III) have been described. An amino acid transporter gene, SLC3A1 (formerly rBAT), was found to be responsible for this disorder. Mutational and linkage analysis demonstrated the presence of genetic heterogeneity in which the SLC3A1 gene is responsible for type I Cystinuria but not for type II or type III. In this study, we report the identification of the Cystinuria type III locus on the long arm of chromosome 19 (19q13.1), obtained after a genomewide search. Pairwise linkage analysis in a series of type III or type II families previously excluded from linkage to the Cystinuria type I locus (SLC3A1 gene) revealed a significant maximum LOD score (zeta max) of 13.11 at a maximum recombination fraction (theta max) of .00, with marker D19S225. Multipoint linkage analysis performed with the use of additional markers from the region placed the Cystinuria type III locus between D19S414 and D19S220. Preliminary data on type II families also seem to place the disease locus for this rare type of Cystinuria at 19q13.1 (significant zeta max = 3.11 at theta max of .00, with marker D19S225).
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Genetic heterogeneity in Cystinuria: the SLC3A1 gene is linked to type I but not to type III Cystinuria
Proceedings of the National Academy of Sciences of the United States of America, 1995Co-Authors: Maria Julia Calonge, Luigi Bisceglia, Leopoldo Zelante, V. Volpini, Ferran Rousaud, L. De Sanctis, Ercole Beccia, Xavier Testar, Xavier EstivillAbstract:Abstract Cystinuria is an autosomal recessive amino-aciduria where three urinary phenotypes have been described (I, II, and III). An amino acid transporter gene, SLC3A1 (formerly rBAT), was found to be responsible for this disorder. To assess whether mutations in SLC3A1 are involved in different Cystinuria phenotypes, linkage with this gene and its nearest marker (D2S119) was analyzed in 22 families with type I and/or type III Cystinuria. Linkage with heterogeneity was proved (alpha = 0.45; P 3.0 at theta = 0.00; alpha = 1), whereas types I/III and III/III were not linked. Our data suggest that type I Cystinuria is due to mutations in the SLC3A1 gene, whereas another locus is responsible for type III. This result establishes genetic heterogeneity for Cystinuria, classically considered as a multiallelic monogenic disease.
Luigi Bisceglia - One of the best experts on this subject based on the ideXlab platform.
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Large rearrangements detected by MLPA, point mutations, and survey of the frequency of mutations within the SLC3A1 and SLC7A9 genes in a cohort of 172 cystinuric Italian patients.
Molecular genetics and metabolism, 2010Co-Authors: Luigi Bisceglia, Lucia Fischetti, Patrizia De Bonis, Orazio Palumbo, Bartolomeo Augello, Pietro Stanziale, Massimo Carella, Leopoldo ZelanteAbstract:Abstract Cystinuria is a rare inherited disorder characterized by defective renal reabsorption of cystine and the dibasic amino acids. SLC3A1 and SLC7A9 have been identified as responsible genes. The large majority of the more than 200 mutations so far identified in the two genes are point mutations, while only few alleles carrying gross genomic alterations have been reported. We screened 39 cystinuric patients for large rearrangements, by two home-made multiplex ligation-dependent probe amplification (MLPA) assays. MLPA analysis led to the identification of 6 different alleles in SLC3A1 and 2 in SLC7A9 accounting for a total of 25 copy number changes, 11 in SLC3A1 and 14 in SLC7A9 . Three large rearrangements in SLC3A1 , deletion of exons 2–4 (E2_E4del), deletion of exons 5–6 (E5_E6del) and duplication of exons 8–9 (E8_E9dup) are novel. A complete SLC7A9 gene deletion was found in three patients. In addition, we report the identification of three novel point mutations in SLC7A9 (p.G105E, p.R250K, c.1416_1417insAC), the frequency and the occurrence of Cystinuria mutations in a cohort of 172 Italian patients. In conclusion, we developed a reliable and robust MLPA analytic method for SLC3A1 and SLC7A9 genes that represents an optimal complement to DNA sequence analysis in patients with Cystinuria, enabling the screening for deletions and duplications.
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Comparison between SLC3A1 and SLC7A9 Cystinuria Patients and Carriers: A Need for a New Classification
Journal of the American Society of Nephrology : JASN, 2002Co-Authors: Luca Dello Strologo, Elon Pras, Luigi Bisceglia, Ercole Beccia, Michele Gallucci, Alberto Ponzone, C. Pontesilli, Vittorino Ricci-barbini, Luisa De Sanctis, Leopoldo ZelanteAbstract:Recent developments in the genetics and physiology of Cystinuria do not support the traditional classification, which is based on the excretion of cystine and dibasic amino acids in obligate heterozygotes. Mutations of only two genes (SLC3A1 and SLC7A9), identified by the International Cystinuria Consortium (ICC), have been found to be responsible for all three types of the disease. The ICC set up a multinational database and collected genetic and clinical data from 224 patients affected by Cystinuria, 125 with full genotype definition. Amino acid urinary excretion patterns of 189 heterozygotes with genetic definition and of 83 healthy controls were also included. All SLC3A1 carriers and 14% of SLC7A9 carriers showed a normal amino acid urinary pattern (i.e., type I phenotype). The rest of the SLC7A9 carriers showed phenotype non-I (type III, 80.5%; type II, 5.5%). This makes the traditional classification imprecise. A new classification is needed: type A, due to two mutations of SLC3A1 (rBAT) on chromosome 2 (45.2% in our database); type B, due to two mutations of SLC7A9 on chromosome 19 (53.2% in this series); and a possible third type, AB (1.6%), with one mutation on each of the above-mentioned genes. Clinical data show that Cystinuria is more severe in males than in females. The two types of Cystinuria (A and B) had a similar outcome in this retrospective study, but the effect of the treatment could not be analyzed. Stone events do not correlate with amino acid urinary excretion. Renal function was clearly impaired in 17% of the patients.
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Functional analysis of mutations in SLC7A9, and genotype-phenotype correlation in non-Type I Cystinuria.
Human molecular genetics, 2001Co-Authors: Mariona Font, Elon Pras, Virginia Nunes, Luigi Bisceglia, Xavier Estivill, Eliahu Golomb, Lídia Feliubadaló, Yitshak Kreiss, Adamo Pio D'adamo, Leopoldo ZelanteAbstract:Cystinuria (OMIM 220100) is a common recessive disorder of renal reabsorption of cystine and dibasic amino acids that results in nephrolithiasis of cystine. Mutations in SLC3A1, which encodes rBAT, cause Type I Cystinuria, and mutations in SLC7A9, which encodes a putative subunit of rBAT (b(o,+)AT), cause non-Type I Cystinuria. Here we describe the genomic structure of SLC7A9 (13 exons) and 28 new mutations in this gene that, together with the seven previously reported, explain 79% of the alleles in 61 non-Type I Cystinuria patients. These data demonstrate that SLC7A9 is the main non-Type I Cystinuria gene. Mutations G105R, V170M, A182T and R333W are the most frequent SLC7A9 missense mutations found. Among heterozygotes carrying these mutations, A182T heterozygotes showed the lowest urinary excretion values of cystine and dibasic amino acids. Functional analysis of mutation A182T after co-expression with rBAT in HeLa cells revealed significant residual transport activity. In contrast, mutations G105R, V170M and R333W are associated to a complete or almost complete loss of transport activity, leading to a more severe urinary phenotype in heterozygotes. SLC7A9 mutations located in the putative transmembrane domains of b(o,+)AT and affecting conserved amino acid residues with a small side chain generate a severe phenotype, while mutations in non-conserved residues give rise to a mild phenotype. These data provide the first genotype-phenotype correlation in non-Type I Cystinuria, and show that a mild urinary phenotype in heterozygotes may associate with mutations with significant residual transport activity.
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localization by linkage analysis of the Cystinuria type iii gene to chromosome 19q13 1
American Journal of Human Genetics, 1997Co-Authors: Luigi Bisceglia, Maria Julia Calonge, Xavier Testar, Michele Gallucci, Alberto Ponzone, Lídia Feliubadaló, Antonio Totaro, Salvatore Melchionda, Judith Garcia, Leopoldo ZelanteAbstract:Cystinuria is an autosomal recessive aminoaciduria in which three urinary phenotypes (I, II, and III) have been described. An amino acid transporter gene, SLC3A1 (formerly rBAT), was found to be responsible for this disorder. Mutational and linkage analysis demonstrated the presence of genetic heterogeneity in which the SLC3A1 gene is responsible for type I Cystinuria but not for type II or type III. In this study, we report the identification of the Cystinuria type III locus on the long arm of chromosome 19 (19q13.1), obtained after a genomewide search. Pairwise linkage analysis in a series of type III or type II families previously excluded from linkage to the Cystinuria type I locus (SLC3A1 gene) revealed a significant maximum LOD score (zeta max) of 13.11 at a maximum recombination fraction (theta max) of .00, with marker D19S225. Multipoint linkage analysis performed with the use of additional markers from the region placed the Cystinuria type III locus between D19S414 and D19S220. Preliminary data on type II families also seem to place the disease locus for this rare type of Cystinuria at 19q13.1 (significant zeta max = 3.11 at theta max of .00, with marker D19S225).
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molecular analysis of the Cystinuria disease gene identification of four new mutations one large deletion and one polymorphism
Human Genetics, 1996Co-Authors: Luigi Bisceglia, Antonio Zorzano, Maria Julia Calonge, Ercole Beccia, Xavier Testar, Michele Gallucci, Luisa De Sanctis, Luca Dello Strologo, G Rizzoni, Xavier EstivillAbstract:A Cystinuria disease gene (rBAT) has recently been identified, but evidence strongly suggests that only Type-I Cystinuria is due to mutations in this gene. Sixteen point mutations and a large deletion causing the disease have so far been described in the rBAT gene sequence. To identify new mutated alleles, genomic DNA was analyzed, after the determination of the entire genomic structure of the rBAT gene, by RNA-single strand conformation polymorphism analysis, an accurate and sensitive method able to detect nucleotide changes. Four new point mutations, a large deletion, and a common intragenic polymorphism were detected. These new mutations increase to 22 the number of mutated alleles so far characterized in rBAT. In addition, the frequency of 21 mutations was assessed in a sample of accurately defined Type-I Cystinuria choromosomes. They account for about 58% of all Type-I chromosomes, mutation M467T being the most common (0.26).
Urs Giger - One of the best experts on this subject based on the ideXlab platform.
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Cystinuria caused by a slc7a9 missense mutation in siamese crossbred littermates in germany
Tierärztliche Praxis Ausgabe K: Kleintiere Heimtiere, 2017Co-Authors: Stephanie Hilton, Keijiro Mizukami, Urs GigerAbstract:Cystinurie wird durch einen Defekt bei der renalen Ruckresorption der Aminosauren Cystin, Ornithin, Lysin und Arginin (COLA) im proximalen Nierentubulus verursacht. Die geringe Loslichkeit von Cystin im leicht sauren Milieu fuhrt zur Bildung von Kristallen und Steinen im Urin. In der letzten Zeit gab es Fortschritte hinsichtlich Diagnostik und Verstandnis der Cystinurie bei unseren Haustieren. Bei Katzen sind beide Geschlechter gleichermasen von der Erkrankung betroffen, unabhangig vom Kastrationsstatus. Trotz der relativen Seltenheit wurden bislang mehr Genmutationen bei Katzen als bei Hunden entdeckt. In dieser Fallstudie wurde ein Wurf Siammischlingskatzen in Deutschland klinisch auf Cystinurie untersucht und auf die bei Katzen bekannten Cystinurie-verursachenden Mutationen getestet. Ein adulter, kastrierter Kater wies Cystinkristalle und eine harnsteininduzierte Harnwegsobstruktion auf, die eine perineale Urethrostomie, Zystotomie und medi zinische Behandlung erforderlich machten. Dieser Kater und ein mannlich-kastriertes Geschwistertier ohne klinische Anzeichen einer Harnwegserkrankung wurden im Nitroprussidtest positiv auf Cystin getestet, hatten erhohte COLA-Werte und waren homozygot fur die Punktmutation p.Val294Glu im SLC7A9 -Gen, das die b 0,+ AT-Untereinheit fur den b 0,+ -COLA-Transporter in der Niere kodiert. Ein weiteres mannliches Geschwistertier zeigte keine Cystinurie und wurde negativ auf die Mutation getestet. Die gleiche SLC7A9 -Mutation lies sich bereits bei jeweils einer Maine-Coon-, Sphinx- und Mittellanghaarkatze in Nordamerika nachweisen, was auf einen gemeinsamen Vorfahren und eine weitere Verbreitung schliesen lasst. Das Screening auf diese Mutation stellt eine einfache und zuverlassige Methode zur Untersuchung von Katzen auf Cystinurie dar und ermoglicht eine gezielte Behandlung betroffener Tiere.
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Cystinuria Associated with Different SLC7A9 Gene Variants in the Cat.
PloS one, 2016Co-Authors: Keijiro Mizukami, Karthik Raj, Carl A. Osborne, Urs GigerAbstract:Cystinuria is a classical inborn error of metabolism characterized by a selective proximal renal tubular defect affecting cystine, ornithine, lysine, and arginine (COLA) reabsorption, which can lead to uroliths and urinary obstruction. In humans, dogs and mice, Cystinuria is caused by variants in one of two genes, SLC3A1 and SLC7A9, which encode the rBAT and bo,+AT subunits of the bo,+ basic amino acid transporter system, respectively. In this study, exons and flanking regions of the SLC3A1 and SLC7A9 genes were sequenced from genomic DNA of cats (Felis catus) with COLAuria and cystine calculi. Relative to the Felis catus-6.2 reference genome sequence, DNA sequences from these affected cats revealed 3 unique homozygous SLC7A9 missense variants: one in exon 5 (p.Asp236Asn) from a non-purpose-bred medium-haired cat, one in exon 7 (p.Val294Glu) in a Maine Coon and a Sphinx cat, and one in exon 10 (p.Thr392Met) from a non-purpose-bred long-haired cat. A genotyping assay subsequently identified another cystinuric domestic medium-haired cat that was homozygous for the variant originally identified in the purebred cats. These missense variants result in deleterious amino acid substitutions of highly conserved residues in the bo,+AT protein. A limited population survey supported that the variants found were likely causative. The remaining 2 sequenced domestic short-haired cats had a heterozygous variant at a splice donor site in intron 10 and a homozygous single nucleotide variant at a branchpoint in intron 11 of SLC7A9, respectively. This study identifies the first SLC7A9 variants causing feline Cystinuria and reveals that, as in humans and dogs, this disease is genetically heterogeneous in cats.
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Feline Cystinuria caused by a missense mutation in the SLC3A1 gene.
Journal of veterinary internal medicine, 2014Co-Authors: Keijiro Mizukami, Karthik Raj, Urs GigerAbstract:Background Cystinuria is an inherited metabolic disease that is relatively common in dogs, but rare in cats and is characterized by defective amino acid reabsorption, leading to cystine urolithiasis. Objectives The aim of this study was to report on a mutation in a cystinuric cat. Animals A male domestic shorthair (DSH) cat with cystine calculi, 11 control cats from Wyoming, and 54 DSH and purebred control cats from elsewhere in the United States. Methods Exons of the SLC3A1 gene were sequenced from genomic DNA of the cystinuric cat and a healthy cat. Genetic screening for the discovered polymorphisms was conducted on all cats. Results A DSH cat showed stranguria beginning at 2 months of age, and cystine calculi were removed at 4 months of age. The cat was euthanized at 6 months of age because of neurological signs possibly related to arginine deficiency. Twenty-five SLC3A1 polymorphisms were observed in the sequenced cats when compared to the feline reference sequence. The cystinuric cat was homozygous for 5 exonic and 8 noncoding SLC3A1 polymorphisms, and 1 of them was a unique missense mutation (c.1342C>T). This mutation results in a deleterious amino acid substitution (p.Arg448Trp) of a highly conserved arginine residue in the rBAT protein encoded by the SLC3A1 gene. This mutation was found previously in cystinuric human patients, but was not seen in any other tested cats. Conclusions and Clinical Importance This study is the first report of an SLC3A1 mutation causing Cystinuria in a cat, and could be used to characterize other cystinuric cats at the molecular level.
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slc3a1 and slc7a9 mutations in autosomal recessive or dominant canine Cystinuria a new classification system
Journal of Veterinary Internal Medicine, 2013Co-Authors: A K Brons, Karthik Raj, Paula S. Henthorn, Junlong Liu, C A Fitzgerald, A C Sewell, Urs GigerAbstract:Cystinuria (OMIA 000256-9615) is one of the first inborn errors of metabolism recognized by Sir Archibald Garrod 1,2 and is an inherited selective renal transport defect 3,4 involving cystine and the dibasic amino acids ornithine, lysine and arginine, collectively known as COLA.4 In contrast to the normal near complete reabsorption of COLA in the proximal renal tubules, these amino acids reach high concentrations in the urine in affected individuals, but only cystine causes a clinical problem.5 The low solubility of cystine in acidic and neutral urine may lead to the formation of cystine crystals and uroliths in the urinary tract,6 which result clinically in stranguria, hematuria, urinary obstruction and renal failure.7,8 In 1823, Cystinuria was the first reported inborn error of metabolism in dogs,9 and now is known to affect >70 canine breeds according to reports of veterinary urolith analysis laboratories worldwide.10,11 Based upon the varied clinical presentations, metabolic derangements and genetic studies, we previously divided canine Cystinuria into type I and non-type I Cystinuria.12 Type I Cystinuria has been characterized in Newfoundlands and Landseers,13 and causes massive aminoaciduria of COLA and juvenile to adult onset calculi formation. It is an autosomal recessive trait affecting both males and females independent of neutering status, although more often cystinuric males show clinical signs of urinary obstruction, presumably due to anatomical differences between males and females.13 In non-type I Cystinuria, exemplified by Mastiffs and related breeds, Scottish Deerhounds, and Irish Terriers, only intact adult males show variable degrees of aminoaciduria and the average age of urolith formation is later than in Newfoundlands. The molecular basis and mode of inheritance of non-type I Cystinuria remain unknown, but it is not an X-chromosomal disorder and appears to be testosterone dependent. a,14 Two genes, SLC3A1 and SLC7A9, encode the subunits of b0,+, the basic amino acid transporter system. 4,15,16 The SLC3A1 gene encodes the extracellular heavy chain referred to as rBAT, and the SLC7A9 gene the light chain called b0,+AT.3 The subunit b0,+AT has 12 transmembrane domains typical of cell membrane transporters and heterodimerizes with rBAT exclusively to form the COLA amino acid transporter.17 Among all the cystinuric dogs to date, only 1 mutation in SLC3A1, an early stop codon precluding the production of the rBAT protein, and leading to the loss of b0,+ function, was identified in cystinuric Newfoundlands in 2000.18 And although the disease was widely recognized in the breed, screening programs for the mutation have markedly decreased the incidence of Cystinuria in Newfoundlands and Landseers worldwide. We report here the clinical, metabolic and molecular genetic characterization of cystinuric Labrador Retrievers, Australian Cattle Dogs, Miniature Pinschers and mixed breed dogs. Because our data demonstrate multiple genetic etiologies and modes of inheritance for Cystinuria, we propose a new expanded classification system for canine Cystinuria.
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Canine Cystinuria: polymorphism in the canine SLC3A1 gene and identification of a nonsense mutation in cystinuric Newfoundland dogs
Human genetics, 2000Co-Authors: Paula S. Henthorn, Junlong Liu, Tanya Gidalevich, Jikang Fang, Margret L. Casal, Donald F. Patterson, Urs GigerAbstract:Cystinuria is an inherited renal and intestinal disease characterized by defective amino acid reabsorption and cystine urolithiasis. Different forms of the disease, designated type I and non-type I in cystinuric humans, can be distinguished clinically and biochemically, and have been associated with mutations in the SLC3A1 (rBAT) and SLC7A9 genes, respectively. Type I Cystinuria is the most common form and is inherited as an autosomal recessive trait in humans. Cystinuria has been recognized in more than 60 breeds of dogs and a severe form, resembling type I Cystinuria, has been characterized in the Newfoundland breed. Here we report the cloning and sequencing of the canine SLC3A1 cDNA and gene, and the identification of a nonsense mutation in exon 2 of the gene in cystinuric Newfoundland dogs. A mutation-specific test was developed for the diagnosis and control of Cystinuria in Newfoundland dogs. In cystinuric dogs of six other breeds, either heterozygosity at the SLC3A1 locus or lack of mutations in the coding region of the SLC3A1 gene were observed, indicating that Cystinuria is genetically heterogeneous in dogs, as it is in humans. The canine homologue of human type I Cystinuria provides the opportunity to use a large animal model to investigate molecular approaches for the treatment of Cystinuria and other renal tubular diseases.
Manuel Palacin - One of the best experts on this subject based on the ideXlab platform.
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Digenic Inheritance in Cystinuria Mouse Model.
PloS one, 2015Co-Authors: Meritxell Espino, Manuel Palacin, Mariona Font-llitjós, Clara Vilches, Eduardo Salido, Esther Prat, Miguel López De Heredia, Virginia NunesAbstract:Cystinuria is an aminoaciduria caused by mutations in the genes that encode the two subunits of the amino acid transport system b0,+, responsible for the renal reabsorption of cystine and dibasic amino acids. The clinical symptoms of Cystinuria relate to nephrolithiasis, due to the precipitation of cystine in urine. Mutations in SLC3A1, which codes for the heavy subunit rBAT, cause Cystinuria type A, whereas mutations in SLC7A9, which encodes the light subunit b0,+AT, cause Cystinuria type B. By crossing Slc3a1-/- with Slc7a9-/- mice we generated a type AB Cystinuria mouse model to test digenic inheritance of Cystinuria. The 9 genotypes obtained have been analyzed at early (2- and 5-months) and late stage (8-months) of the disease. Monitoring the lithiasic phenotype by X-ray, urine amino acid content analysis and protein expression studies have shown that double heterozygous mice (Slc7a9+/-Slc3a1+/-) present lower expression of system b0,+ and higher hyperexcretion of cystine than single heterozygotes (Slc7a9+/-Slc3a1+/+ and Slc7a9+/+Slc3a1+/-) and give rise to lithiasis in 4% of the mice, demonstrating that Cystinuria has a digenic inheritance in this mouse model. Moreover in this study it has been demonstrated a genotype/phenotype correlation in type AB Cystinuria mouse model providing new insights for further molecular and genetic studies of Cystinuria patients.
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pathophysiology and treatment of Cystinuria
Nature Reviews Nephrology, 2010Co-Authors: Josep Chillarón, Antonio Zorzano, Virginia Nunes, David S. Goldfarb, Mariona Fontllitjos, Joana Fort, Manuel PalacinAbstract:Cystinuria is a primary inherited aminoaciduria caused by mutations in the genes that encode the two subunits (neutral and basic amino acid transport protein rBAT and b(0,+)-type amino acid transporter 1) of the amino acid transport system b(0,+). This autosomal recessive disorder (in which few cases show dominant inheritance) causes a failure in the reabsorption of filtered cystine and dibasic amino acids in the proximal tubule. The clinical symptoms of this disease are caused by the loss of poorly soluble cystine, which precipitates to form stones. Although rare, the prevalence of Cystinuria is sufficiently high that the disease results in a substantial contribution to pediatric renal lithiasis. A thorough understanding of cystine transport processes over the past 15 years and the genetic abnormalities responsible for the disease has led to a new classification of Cystinuria and recognition that some cases result from an autosomal dominant etiology with incomplete penetrance. This Review examines the molecular and mechanistic effects of some of the mutations that cause Cystinuria based on our current understanding of the structural and cellular biology of system b(0,+). This Review also describes the current treatments to prevent recurrent cystine lithiasis.
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Slc7a9-deficient mice develop Cystinuria non-I and cystine urolithiasis
Human molecular genetics, 2003Co-Authors: Lídia Feliubadaló, Antonio Zorzano, Manuel Palacin, Ferran Rousaud, Maria L. Arbonés, Sandra Mañas, Josep Chillarón, Joana Visa, Margot Rodés, Virginia NunesAbstract:Cystinuria is a common recessive disorder of renal reabsorption of cystine and dibasic amino acids that results in urolithiasis of cystine. Cystinuria is caused by defects in the amino acid transport system b0,+ (i.e. the rBAT/b0,+AT heteromeric complex). Mutations in SLC3A1, encoding rBAT, cause Cystinuria type A, characterized by a silent phenotype in heterozygotes (phenotype I). Mutations in SLC7A9, encoding b0,+AT, cause Cystinuria type B, in which heterozygotes in most cases hyperexcrete cystine and dibasic amino acids (phenotype non-I). To facilitate in vivo investigation of b0,+AT in Cystinuria, Slc7a9 knockout mice have been generated. Expression of b0,+AT protein is completely abolished in the kidney of Slc7a9-/- mice ('Stones'). In contrast, Stones expressed significant amounts of rBAT protein, which is covalently linked to unidentified light subunit(s). Stones mice present a dramatic hyperexcretion of cystine and dibasic amino acids, while Slc7a9+/- mice show moderate but significant hyperexcretion of these amino acids (phenotype non-I). Forty-two per cent of Stones mice develop cystine calculi in the urinary system. Calculi develop during the first month of life and grow throughout the life span of the animals. Histopathology in kidney reveals typical changes for urolithiasis (tubular and pelvic dilatation, tubular necrosis, tubular hyaline droplets and chronic interstitial nephritis). The fact that some Stones mice, generated in a mixed genetic background, develop cystine calculi from an early age, while others do not develop them in their first year of life, suggests the involvement of modifier genes in the lithiasis phenotype. Thus, Stones provide a valid model of Cystinuria which can be used in the study of genetic, pharmacological and environmental factors involved in cystine urolithiasis.
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slc7a9 mutations in all three Cystinuria subtypes
Kidney International, 2002Co-Authors: Daniel Leclerc, Manuel Palacin, Marylise Boutros, Daniel SuhAbstract:SLC7A9 mutations in all three Cystinuria subtypes. Background Cystinuria is an inherited disorder of cystine and dibasic amino acid transport in kidney. Subtypes are defined by the urinary cystine excretion patterns of the obligate heterozygous parents: Type I/N (fully recessive or silent); Type II/N (high excretor); Type III/N (moderate excretor). The first gene implicated in Cystinuria ( SLC3A1 ) is associated with the Type I urinary phenotype. A second Cystinuria gene ( SLC7A9 ) was recently isolated, and mutations of this gene were associated with dominant (non-Type I) Cystinuria alleles. Here we report genotype-phenotype studies of SLC7A9 mutations in a cohort of well-characterized Cystinuria probands and their family members. Methods Individual exons of the SLC7A9 gene were screened by single strand conformation polymorphism (SSCP) analysis and sequencing of abnormally migrating fragments. Results Seven mutations were identified. A singlebp insertion (799insA) was present in four patients: on Type III alleles in two patients and on Type II alleles in two patients. These results suggest that Type II and Type III may be caused by the same mutation and, therefore, other factors must influence urinary cystine excretion. A 4bp deletion in intron 12 (IVS12+4delAGTA) and a missense mutation (1245G→A, A354T) were identified on Type III alleles. A nonsense codon (1491G→T, E436X) and a possible splicing mutation (IVS9-17G→A) were seen in a Type I/III patient, but the mutations could not be assigned to particular alleles. Of additional interest were two missense mutations (316T→C, I44T and 967C→T, P261L) linked to Type I alleles. Conclusion Our results provide evidence that some SLC7A9 mutations may be associated with fully recessive (Type I) forms of Cystinuria. We also demonstrate SLC7A9 mutations in dominant Types II and III Cystinuria. The finding of SLC7A9 mutations in all three subtypes underscores the complex interactions between specific Cystinuria genes and other factors influencing cystine excretion. A simpler phenotypic classification scheme (recessive and dominant) for Cystinuria is warranted.
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no evidence for point mutations in the novel renal cystine transporter agt1 slc7a13 contributing to the etiology of Cystinuria
BMC Nephrology, 2018Co-Authors: Kathrin Olschok, Sven Lahme, Udo Vester, Ingo Kurth, Thomas EggermannAbstract:Cystinuria is caused by the defective renal reabsorption of cystine and dibasic amino acids, and results in cystine stone formation. So far, mutations in two genes have been identified as causative. The SLC3A1/rBAT gene encodes the heavy subunit of the heterodimeric rBAT-b0,+AT transporter, whereas the light chain is encoded by the SLC7A9/ b0,+AT gene. In nearly 85% of patients mutations in both genes are detectable, but a significant number of patients currently remains without a molecular diagnosis. Thus, the existence of a further Cystinuria gene had been suggested, and the recently identified AGT1/SLC7A13 represents the long-postulated partner of rBAT and third Cystinuria candidate gene. We screened a cohort of 17 Cystinuria patients for SLC7A13 variants which were negative for SLC3A1 and SLC7A9 mutations. Despite strong evidences for an involvement of SLC7A13 mutations in Cystinuria, we could not confirm a relevant role of SLC7A13 for the disease. With the exclusion of SLC7A13/AGT1 as the third Cystinuria gene accounting for the SLC3A1 and SLC7A9 mutation negative cases, it becomes obvious that other genetic factors should be responsible for the Cystinuria phenotype in nearly 15% of patients.
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No evidence for point mutations in the novel renal cystine transporter AGT1/SLC7A13 contributing to the etiology of Cystinuria
'Springer Science and Business Media LLC', 2018Co-Authors: Kathrin Olschok, Sven Lahme, Udo Vester, Ingo Kurth, Thomas EggermannAbstract:Abstract Background Cystinuria is caused by the defective renal reabsorption of cystine and dibasic amino acids, and results in cystine stone formation. So far, mutations in two genes have been identified as causative. The SLC3A1/rBAT gene encodes the heavy subunit of the heterodimeric rBAT-b0,+AT transporter, whereas the light chain is encoded by the SLC7A9/ b 0,+ AT gene. In nearly 85% of patients mutations in both genes are detectable, but a significant number of patients currently remains without a molecular diagnosis. Thus, the existence of a further Cystinuria gene had been suggested, and the recently identified AGT1/SLC7A13 represents the long-postulated partner of rBAT and third Cystinuria candidate gene. Methods We screened a cohort of 17 Cystinuria patients for SLC7A13 variants which were negative for SLC3A1 and SLC7A9 mutations. Results Despite strong evidences for an involvement of SLC7A13 mutations in Cystinuria, we could not confirm a relevant role of SLC7A13 for the disease. Conclusion With the exclusion of SLC7A13/AGT1 as the third Cystinuria gene accounting for the SLC3A1 and SLC7A9 mutation negative cases, it becomes obvious that other genetic factors should be responsible for the Cystinuria phenotype in nearly 15% of patients
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2p21 Deletions in hypotonia-Cystinuria syndrome.
European journal of medical genetics, 2012Co-Authors: Thomas Eggermann, Klaus Zerres, Andreas Venghaus, Sabrina Spengler, Bernd Denecke, Michael Baudis, Regina EnsenauerAbstract:The significant role of the SLC3A1 gene in the aetiology of Cystinuria is meanwhile well established and more than 130 point mutations have been reported. With the reports on genomic deletions including at least both SLC3A1 and the neighboured PREPL gene the spectrum of Cystinuria mutations and of clinical symptoms could recently be enlarged: patients homozygous for these deletions suffer from a general neonatal hypotonia and growth retardation in addition to Cystinuria. The hypotonia in these hypotonia-Cystinuria (HCS) patients has been attributed to the total loss of the PREPL protein. Here we report on the clinical course and molecular findings in a HCS patient compound heterozygote for a new deletion in 2p21 and a previously reported deletion, both identified by molecular karyotyping. The diagnostic workup in this patient illustrates the need for a careful clinical examination in context with powerful molecular genetic tools in patients with unusual phenotypes. The identification of unique genomic alterations and their interpretation serves as a prerequisite for the individual counselling of patients and their families. In diagnostic strategies to identify the molecular basis of both Cystinuria and hypotonia 2p21 deletions should be considered as the molecular basis of the phenotype.
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Identification of novel Cystinuria mutations in pediatric patients.
Journal of pediatric urology, 2006Co-Authors: Eva Brauers, Udo Vester, Klaus Zerres, Christa Schmidt, Kamil K. Hozyasz, Bozena Gołabek, Małgorzata Słowik, Thomas EggermannAbstract:Abstract Objective Cystinuria is a common inherited disorder of renal reabsorption of cystine and the dibasic amino acids. So far, mutations in two genes ( SLC3A1 and SLC7A9 ) have been identified in Cystinuria patients. Molecular searches for Cystinuria mutations show that their distribution depends on the ethnic origin of the patients, but have not allowed the detection of 100% of variants. Pediatric patients representing a severe form of the disease appear to carry other mutations than those patients referred from urological centers. We analysed patients with an age of manifestation less than 15 years for mutations in the two Cystinuria genes. Patients and methods We screened 17 patients for mutations in SLC3A1 and SLC7A9 , 15 of whom were younger than 16 years at first stone formation. The search for mutations used PCR-based standard techniques, and was focused on point mutations and larger deletions and duplications in both genes. Results Apart from detection of mutations in approximately 70% of patients but identification of only 53% of alleles, we detected three novel mutations as well as three new polymorphisms. Conclusion The detection rate in young Cystinuria patients is lower than that in older patients, and there is a different pattern of variants. There is evidence for other (probably genetic) factors being involved in the pathophysiology of Cystinuria.
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search for mutations in slc1a5 19q13 in Cystinuria patients
Journal of Inherited Metabolic Disease, 2005Co-Authors: Eva Brauers, Udo Vester, Klaus Zerres, Thomas EggermannAbstract:To elucidate whether SLC1A5 is involved in the aetiology of Cystinuria, we screened two non-type I Cystinuria families without detectable mutations inSLC7A9 (and SLC3A1) but compatible with linkage to 19q13 for genomic variants in SLC1A5. Despite evidence for an involvement of SLC1A5 in the aetiology of Cystinuria, we could not identify any mutation in this gene in the two families. With SLC1A5, a further candidate gene for Cystinuria can be excluded as being involved in the pathogenesis of this disease in these two families. Of course, there remains the possibility that other genes are involved in Cystinuria; further molecular studies will clarify the complex nature of this disorder.
