The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform
Stefan Andersson - One of the best experts on this subject based on the ideXlab platform.
-
17β-hydroxysteroid dehydrogenase 3 deficiency in a male pseudohermaphrodite
Fertility and sterility, 2007Co-Authors: Lindsay M. Mains, Annika Lindqvist, Stefan Andersson, Babak Vakili, Yves Lacassie, John A. RockAbstract:Objective To present the clinical, biochemical, and Genetic features of a male pseudohermaphrodite whose condition was caused by 17β-hydroxysteroid dehydrogenase 3 (17β-HSD3) deficiency. Design Case report. Setting Gynecology practice in a university teaching hospital. Patient(s) A 15-year-old black American male pseudohermaphrodite with 17β-HSD3 deficiency. Intervention(s) Laboratory evaluation, Genetic mutation analysis, bilateral gonadectomy, and hormone replacement. Main Outcome Measure(s) Endocrinologic evaluation and Genetic analysis. Result(s) A diagnosis of 17β-HSD3 deficiency made on the basis of hormone evaluation was confirmed through Genetic mutation analysis of the HSD17B3 Gene. Female phenotype was attained after gonadectomy, passive vaginal dilatation, and hormone therapy. Conclusion(s) Deficiency of 17β-HSD3 was diagnosed in this patient on the basis of endocrinologic evaluation and was confirmed with Genetic mutation analysis. The patient was able to retain her female sexual identity after surgical and medical treatment.
-
Phenotypic variability in 17β‐hydroxysteroid dehydrogenase‐3 deficiency and diagnostic pitfalls
Clinical endocrinology, 2007Co-Authors: Yung Seng Lee, Stefan Andersson, Richard J. Auchus, Jeremy Kirk, Richard Stanhope, Derek I. Johnston, Sharon Harland, Ieuan A. HughesAbstract:Objective 17beta-hydroxysteroid dehydrogenase type 3 isoenzyme (17beta-HSD3) is required to produce testosterone for male sex differentiation. Mutations in the HSD17B3 Gene cause 17betaHSD3 deficiency and result in XY sex reversal of varying degree. We report the phenotypes of 14 subjects with 17betaHSD3 deficiency in relation to sex of rearing, androgen production, and HSD17B3 mutations. Design Cases were identified through the Cambridge Disorders of Sex Development Database where detailed clinical information was recorded, results of hCG stimulation tests were available, and HSD17B3 mutation was identified. Results Fourteen subjects from seven pedigrees (four consanguineous) had the following seven mutations: A56T, N130S, E215D, S232L, C268Y, V205E, and a novel mutation M197K. XY sex reversal was classified as complete in 10 infants at birth. Inguinal masses suggestive of androgen insensitivity syndrome (AIS) occurred in five infants. Contrasexual virilization reminiscent of 5alpha-reductase deficiency occurred in four subjects at puberty. The median (range) testosterone : androstenedione (T/A) ratio after a short hCG stimulation test was 0.32 (0.12-3.4). The S232L mutation identified in three affected family members caused isolated, severe hypospadias in one member who was raised male; virilization occurred despite in vitro studies showing an inactive mutant enzyme. Ratios of T/A in this pedigree were more than 0.8. Conclusion XY sex reversal is sufficiently variable in 17betaHSD3 deficiency to cause problems in accurate diagnosis, particularly in distinguishing it from AIS. It should be considered in undervirilized male infants with normal Wolffian duct structures, absent Mullerian ducts, and normal adrenal steroid biosynthesis; or when an assigned female subject virilizes at puberty. Elevated hCG-stimulated T/A ratio may occur, and sex of rearing may not be concordant within affected families with the same HSD17B3 mutation. The T/A ratio, mutation analysis and functional analysis of the mutant enzyme taken in isolation, respectively, may not conclusively establish a diagnosis of 17betaHSD3 deficiency in undervirilized male subjects; the reasons for these discrepancies remain unknown.
-
Substitution Mutation C268Y Causes 17β-Hydroxysteroid Dehydrogenase 3 Deficiency1
The Journal of clinical endocrinology and metabolism, 2001Co-Authors: Annika Lindqvist, Ieuan A. Hughes, Stefan AnderssonAbstract:The 17β-hydroxysteroid dehydrogenase (HSD) type 3 isozyme catalyzes the conversion of androstenedione to testosterone in the testis. Deleterious mutations in the HSD17B3 Gene cause undermasculinization in Genetic males attributable to impaired testosterone biosynthesis. Hence, a hallmark of this autosomal recessive disorder is a decreased plasma testosterone-to-androstenedione ratio. Here, a novel C268Y substitution mutation in exon 10 of the HSD17B3 Gene, in a subject with 17β-HSD 3 deficiency, is reported. Reconstitution experiments with recombinant protein reveal that substitution of tyrosine for cysteine at position 268 of 17β-HSD type 3 abrogates the enzymatic activity. This finding brings to 20 the number of mutations in the HSD17B3 Gene that cause male undermasculinization.
-
17Beta-hydroxysteroid dehydrogenase-3 deficiency: diagnosis, phenotypic variability, population Genetics, and worldwide distribution of ancient and de novo mutations.
The Journal of clinical endocrinology and metabolism, 1999Co-Authors: Alm Boehmer, Stefan Andersson, Albert O. Brinkmann, Lodewijk A. Sandkuijl, D. J. J. Halley, Martinus F. Niermeijer, Fh De Jong, Hülya Kayserili, M.a. De Vroede, B.j. OttenAbstract:b-Hydroxysteroid dehydrogenase-3 (17bHSD3) deficiency is an autosomal recessive form of male pseudohermaphroditism caused by mutations in the HSD17B3 Gene. In a nationwide study on male pseudohermaphroditism among all pediatric endocrinol- ogists and clinical Geneticists in The Netherlands, 18 17bHSD3- deficient index cases were identified, 12 of whom initially had received the tentative diagnosis androgen insensitivity syndrome (AIS). The phenotypes and genotypes of these patients were stud- ied. Endocrine diagnostic methods were evaluated in comparison to mutation analysis of the HSD17B3 Gene. RT-PCR studies were performed on testicular ribonucleic acid of patients homozygous for two different splice site mutations. The minimal incidence of 17bHSD3 deficiency in The Netherlands and the corresponding carrier frequency were calculated. Haplotype analysis of the chro- mosomal region of the HSD17B3 Gene in Europeans, North Amer- icans, Latin Americans, Australians, and Arabs was used to es- tablish whether recurrent identical mutations were ancient or had repeatedly occurred de novo. In genotypically identical cases, phenotypic variation for exter- nal sexual development was observed. Gonadotropin-stimulated serum testosterone/androstenedione ratios in 17bHSD3-deficient patients were discriminative in all cases and did not overlap with ratios in normal controls or with ratios in AIS patients. In all investigated patients both HSD17B3 alleles were mutated. The intronic mutations 325 1 4;A3 T and 655-1;G3 A disrupted nor- mal splicing, but a small amount of wild-type messenger ribonu- cleic acid was still made in patients homozygous for 655-1;G3 A. The minimal incidence of 17bHSD3 deficiency in The Netherlands was shown to be 1:147,000, with a heterozygote frequency of 1:135. At least 4 mutations, 325 1 4;A3 T, N74T, 655-1;G3 A, and R80Q, found worldwide, appeared to be ancient and originating from Genetic founders. Their dispersion could be reconstructed through historical analysis. The HSD17B3 Gene mutations 326 -1;G3 C and P282L were de novo mutations. 17bHSD3 deficiency can be reliably diagnosed by endocrine eval- uation and mutation analysis. Phenotypic variation can occur be- tween families with the same homozygous mutations. The inci- dence of 17bHSD3 deficiency is 0.65 times the incidence of AIS, which is thought to be the most frequent known cause of male pseudohermaphroditism without dysgenic gonads. A global inven- tory of affected cases demonstrated the ancient origin of at least four mutations. The mutational history of this Genetic locus offers views into human diversity and disease, provided by national and international collaboration. (J Clin Endocrinol Metab 84: 4713- 4721, 1999)
-
Deleterious Missense Mutations and Silent Polymorphism in the Human 17β-Hydroxysteroid Dehydrogenase 3 Gene (HSD17B3)
The Journal of clinical endocrinology and metabolism, 1998Co-Authors: Nabil Moghrabi, Ieuan A. Hughes, Andrea Dunaif, Stefan AnderssonAbstract:Isozymes of 17β-hydroxysteroid dehydrogenase (17βHSD) regulate levels of bioactive androgens and estrogens in a variety of tissues. For example, the 17βHSD type 3 isozyme catalyzes the conversion of the inactive C19-steroid androstenedione to the biologically active androgen, testosterone, in the testis. Testosterone is essential for the correct development of male internal and external genitalia; hence, deleterious mutations in the HSD17B3 Gene give rise to a rare form of male pseudohermaphroditism termed 17βHSD deficiency. Here, 2 additional missense mutations in the HSD17B3 Gene in subjects with 17βHSD deficiency are described. One mutation (A56T) impairs enzyme function by affecting NADPH cofactor binding. A second mutation (N130S) led to complete loss of enzyme activity. Also, a single base pair polymorphism in exon 11 of the HSD17B3 Gene is described. The polymorphic A allele encodes a protein with a serine rather than a glycine at position 289 (GGT → AGT). The frequency of the G allele (Gly) was 0....
Alex Odermatt - One of the best experts on this subject based on the ideXlab platform.
-
Biochemical Analysis of Four Missense Mutations in the HSD17B3 Gene Associated With 46,XY Disorders of Sex Development in Egyptian Patients.
The journal of sexual medicine, 2017Co-Authors: Roger T. Engeli, Heba A. Hassan, Inas Mazen, Yehia Z. Gad, Mona L Essawi, Maria Tsachaki, Christoph P. Sager, A. K. Kamel, Alex OdermattAbstract:Abstract Background Mutations in the HSD17B3 Gene are associated with a 46,XY disorder of sexual development (46,XY DSD) as a result of low testosterone production during embryoGenesis. Aim To elucidate the molecular basis of the disorder by chemically analyzing four missense mutations in HSD17B3 (T54A, M164T, L194P, G289S) from Egyptian patients with 46,XY DSD. Methods Expression plasmids for wild-type 17β-hydroxysteroid hydrogenase type 3 (17β-HSD3) and mutant enzymes Generated by site-directed mutaGenesis were transiently transfected into human HEK-293 cells. Protein expression was verified by western blotting and activity was determined by measuring the conversion of radiolabeled Δ4-androstene-3,17-dione to testosterone. Application of a homology model provided an explanation for the observed effects of the mutations. Outcomes Testosterone formation by wild-type and mutant 17β-HSD3 enzymes was compared. Results Mutations T54A and L194P, despite normal protein expression, completely abolished 17β-HSD3 activity, explaining their severe 46,XY DSD phenotype. Mutant M164T could still produce testosterone, albeit with significantly lower activity compared with wild-type 17β-HSD3, resulting in ambiguous genitalia or a microphallus at birth. The substitution G289S represented a polymorphism exhibiting comparable activity to wild-type 17β-HSD3. Sequencing of the SRD5A2 Gene in three siblings bearing the HSD17B3 G289S polymorphism disclosed the homozygous Y91H mutation in the former Gene, thus explaining the 46,XY DSD presentations. Molecular modeling analyses supported the biochemical observations and predicted a disruption of cofactor binding by mutations T54A and M164T and of substrate binding by L196P, resulting in the loss of enzyme activity. In contrast, the G289S substitution was predicted to disturb neither the three-dimensional structure nor enzyme activity. Clinical Translation Biochemical analysis of mutant 17β-HSD3 enzymes is necessary to understand genotype-phenotype relationships. Strengths and Limitations Biochemical analysis combined with molecular modeling provides insight into disease mechanism. However, the stability of mutant proteins in vivo cannot be predicted by this approach. Conclusion The 17β-HSD3 G289S substitution, previously reported in other patients with 46,XY DSD, is a polymorphism that does not cause the disorder; thus, further sequence analysis was required and disclosed a mutation in SRD5A2, explaining the cause of 46,XY DSD in these patients. Engeli RT, Tsachaki M, Hassan HA, et al. Biochemical Analysis of Four Missense Mutations in the HSD17B3 Gene Associated With 46,XY Disorders of Sex Development in Egyptian Patients. J Sex Med 2017;14:1165–1174.
-
Novel cases of Tunisian patients with mutations in the Gene encoding 17β-hydroxysteroid dehydrogenase type 3 and a founder effect.
The Journal of steroid biochemistry and molecular biology, 2016Co-Authors: Bochra Ben Rhouma, Hassen Kamoun, Roger T. Engeli, Alex Odermatt, Fakhri Kallabi, Nadia Mahfoudh, Afif Ben Mahmoud, Leila Keskes, Neila BelguithAbstract:17β-Hydroxysteroid dehydrogenase type 3 (17β-HSD3) is expressed almost exclusively in the testis and converts Δ4-androstene-3,17-dione to testosterone. Mutations in the HSD17B3 Gene causing 17β-HSD3 deficiency are responsible for a rare recessive form of 46, XY Disorders of Sex Development (46, XY DSD). We report novel cases of Tunisian patients with 17β-HSD3 deficiency due to previously reported mutations, i.e. p.C206X and p.G133R, as well as a case with the novel compound heterozygous mutations p.C206X and p.Q176P. Moreover, the previously reported polymorphism p.G289S was identified in a heterozygous state in combination with a novel non-coding variant c.54G>T, also in a heterozygous state, in a male patient presenting with micropenis and low testosterone levels. The identification of four different mutations in a cohort of eight patients confirms the Generally observed Genetic heteroGeneity of 17β-HSD3 deficiency. Nevertheless, analysis of DNA from 272 randomly selected healthy controls from the same geographic area (region of Sfax) revealed a high carrier frequency for the p.C206X mutation of approximately 1 in 40. Genotype reconstruction of the affected pedigree members revealed that all p.C206X mutation carriers harbored the same haplotype, indicating inheritance of the mutation from a common ancestor. Thus, the identification of a founder effect and the elevated carrier frequency of the p.C206X mutation emphasize the importance to consider this mutation in the diagnosis and Genetic counseling of affected 17β-HSD3 deficiency pedigrees in Tunisia.
-
Biochemical analyses and molecular modeling explain the functional loss of 17β-hydroxysteroid dehydrogenase 3 mutant G133R in three Tunisian patients with 46, XY Disorders of Sex Development.
The Journal of steroid biochemistry and molecular biology, 2015Co-Authors: Roger T. Engeli, Bochra Ben Rhouma, Neila Belguith, Maria Tsachaki, Christoph P. Sager, Leila Keskes, Julia Birk, Faiza Fakhfakh, Alex OdermattAbstract:Mutations in the HSD17B3 Gene resulting in 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) deficiency cause 46, XY Disorders of Sex Development (46, XY DSD). Approximately 40 different mutations in HSD17B3 have been reported; only few mutant enzymes have been mechanistically investigated. Here, we report novel compound heterozygous mutations in HSD17B3, composed of the nonsense mutation C206X and the missense mutation G133R, in three Tunisian patients from two non-consanguineous families. Mutants C206X and G133R were constructed by site-directed mutaGenesis and expressed in HEK-293 cells. The truncated C206X enzyme, lacking part of the substrate binding pocket, was moderately expressed and completely lost its enzymatic activity. Wild-type 17β-HSD3 and mutant G133R showed comparable expression levels and intracellular localization. The conversion of Δ4-androstene-3,17-dione (androstenedione) to testosterone was almost completely abolished for mutant G133R compared with wild-type 17β-HSD3. To obtain further mechanistic insight, G133 was mutated to alanine, phenylalanine and glutamine. G133Q and G133F were almost completely inactive, whereas G133A displayed about 70% of wild-type activity. Sequence analysis revealed that G133 on 17β-HSD3 is located in a motif highly conserved in 17β-HSDs and other short-chain dehydrogenase/reductase (SDR) enzymes. A homology model of 17β-HSD3 predicted that arginine or any other bulky residue at position 133 causes steric hindrance of cofactor NADPH binding, whereas substrate binding seems to be unaffected. The results indicate an essential role of G133 in the arrangement of the cofactor binding pocket, thus explaining the loss-of-function of 17β-HSD3 mutant G133R in the patients investigated.
Ieuan A. Hughes - One of the best experts on this subject based on the ideXlab platform.
-
The dilemma of the gender assignment in a Portuguese adolescent with disorder of sex development due to 17β-hydroxysteroid-dehydrogenase type 3 enzyme deficiency
Endocrinology diabetes & metabolism case reports, 2014Co-Authors: Carla Costa, Ieuan A. Hughes, Cíntia Castro-correia, Alda Mira-coelho, Bessa Monteiro, Joaquim Monteiro, Manuel FontouraAbstract:Summary The development of male internal and external genitalia in an XY fetus requires a complex interplay of many critical Genes, enzymes, and cofactors. The enzyme 17b-hydroxysteroid-dehydrogenase type 3 (17bHSD3) is present almost exclusively in the testicles and converts Delta 4-androstenodione (D4) to testosterone. A deficiency in this enzyme is rare and is a frequently misdiagnosed autosomal recessive cause of 46,XY, disorder of sex development. The case report is of a 15-year-old adolescent, who was raised according to female gender. At puberty, the adolescent had a severe virilization and primary amenorrhea. The physical examination showed a male phenotype with micropenis and blind vagina. The Tanner stage was A3B1P4, nonpalpable gonads. The karyotype revealed 46,XY. The endocrinology study revealed: testosteroneZ2.38 ng/ml, D4O10.00 ng/ml, and low testosterone/D4 ratioZ0.23. Magnetic resonance imaging of the abdominal–pelvic showed the presence of testicles in inguinal canal, seminal vesicle, prostate, micropenis, and absence of uterus and vagina. The Genetic study confirmed the mutation p.Glu215Asp on HSD17B3 Gene in homozygosity. The dilemma of sex reassignment was seriously considered when the diagnosis was made. During all procedures the patient was accompanied by a child psychiatrist/psychologist. The teenager desired to continue being a female, so gonadectomy was performed. Estrogen therapy and surgical procedure to change external genitalia was carried out. In this case, there was a severe virilization at puberty. It is speculated to be due to a partial activity of 17bHSD3 in the testicles and/or extratesticular ability to convert D 4t o testosterone by 17bHSD5. Prenatal exposure of the brain to androgens has increasingly been put forward as a critical factor in gender identity development, but in this case the social factor was more important for the gender assignment.
-
Phenotypic variability in 17β‐hydroxysteroid dehydrogenase‐3 deficiency and diagnostic pitfalls
Clinical endocrinology, 2007Co-Authors: Yung Seng Lee, Stefan Andersson, Richard J. Auchus, Jeremy Kirk, Richard Stanhope, Derek I. Johnston, Sharon Harland, Ieuan A. HughesAbstract:Objective 17beta-hydroxysteroid dehydrogenase type 3 isoenzyme (17beta-HSD3) is required to produce testosterone for male sex differentiation. Mutations in the HSD17B3 Gene cause 17betaHSD3 deficiency and result in XY sex reversal of varying degree. We report the phenotypes of 14 subjects with 17betaHSD3 deficiency in relation to sex of rearing, androgen production, and HSD17B3 mutations. Design Cases were identified through the Cambridge Disorders of Sex Development Database where detailed clinical information was recorded, results of hCG stimulation tests were available, and HSD17B3 mutation was identified. Results Fourteen subjects from seven pedigrees (four consanguineous) had the following seven mutations: A56T, N130S, E215D, S232L, C268Y, V205E, and a novel mutation M197K. XY sex reversal was classified as complete in 10 infants at birth. Inguinal masses suggestive of androgen insensitivity syndrome (AIS) occurred in five infants. Contrasexual virilization reminiscent of 5alpha-reductase deficiency occurred in four subjects at puberty. The median (range) testosterone : androstenedione (T/A) ratio after a short hCG stimulation test was 0.32 (0.12-3.4). The S232L mutation identified in three affected family members caused isolated, severe hypospadias in one member who was raised male; virilization occurred despite in vitro studies showing an inactive mutant enzyme. Ratios of T/A in this pedigree were more than 0.8. Conclusion XY sex reversal is sufficiently variable in 17betaHSD3 deficiency to cause problems in accurate diagnosis, particularly in distinguishing it from AIS. It should be considered in undervirilized male infants with normal Wolffian duct structures, absent Mullerian ducts, and normal adrenal steroid biosynthesis; or when an assigned female subject virilizes at puberty. Elevated hCG-stimulated T/A ratio may occur, and sex of rearing may not be concordant within affected families with the same HSD17B3 mutation. The T/A ratio, mutation analysis and functional analysis of the mutant enzyme taken in isolation, respectively, may not conclusively establish a diagnosis of 17betaHSD3 deficiency in undervirilized male subjects; the reasons for these discrepancies remain unknown.
-
Substitution Mutation C268Y Causes 17β-Hydroxysteroid Dehydrogenase 3 Deficiency1
The Journal of clinical endocrinology and metabolism, 2001Co-Authors: Annika Lindqvist, Ieuan A. Hughes, Stefan AnderssonAbstract:The 17β-hydroxysteroid dehydrogenase (HSD) type 3 isozyme catalyzes the conversion of androstenedione to testosterone in the testis. Deleterious mutations in the HSD17B3 Gene cause undermasculinization in Genetic males attributable to impaired testosterone biosynthesis. Hence, a hallmark of this autosomal recessive disorder is a decreased plasma testosterone-to-androstenedione ratio. Here, a novel C268Y substitution mutation in exon 10 of the HSD17B3 Gene, in a subject with 17β-HSD 3 deficiency, is reported. Reconstitution experiments with recombinant protein reveal that substitution of tyrosine for cysteine at position 268 of 17β-HSD type 3 abrogates the enzymatic activity. This finding brings to 20 the number of mutations in the HSD17B3 Gene that cause male undermasculinization.
-
Deleterious Missense Mutations and Silent Polymorphism in the Human 17β-Hydroxysteroid Dehydrogenase 3 Gene (HSD17B3)
The Journal of clinical endocrinology and metabolism, 1998Co-Authors: Nabil Moghrabi, Ieuan A. Hughes, Andrea Dunaif, Stefan AnderssonAbstract:Isozymes of 17β-hydroxysteroid dehydrogenase (17βHSD) regulate levels of bioactive androgens and estrogens in a variety of tissues. For example, the 17βHSD type 3 isozyme catalyzes the conversion of the inactive C19-steroid androstenedione to the biologically active androgen, testosterone, in the testis. Testosterone is essential for the correct development of male internal and external genitalia; hence, deleterious mutations in the HSD17B3 Gene give rise to a rare form of male pseudohermaphroditism termed 17βHSD deficiency. Here, 2 additional missense mutations in the HSD17B3 Gene in subjects with 17βHSD deficiency are described. One mutation (A56T) impairs enzyme function by affecting NADPH cofactor binding. A second mutation (N130S) led to complete loss of enzyme activity. Also, a single base pair polymorphism in exon 11 of the HSD17B3 Gene is described. The polymorphic A allele encodes a protein with a serine rather than a glycine at position 289 (GGT → AGT). The frequency of the G allele (Gly) was 0....
Neila Belguith - One of the best experts on this subject based on the ideXlab platform.
-
Novel cases of Tunisian patients with mutations in the Gene encoding 17β-hydroxysteroid dehydrogenase type 3 and a founder effect.
The Journal of steroid biochemistry and molecular biology, 2016Co-Authors: Bochra Ben Rhouma, Hassen Kamoun, Roger T. Engeli, Alex Odermatt, Fakhri Kallabi, Nadia Mahfoudh, Afif Ben Mahmoud, Leila Keskes, Neila BelguithAbstract:17β-Hydroxysteroid dehydrogenase type 3 (17β-HSD3) is expressed almost exclusively in the testis and converts Δ4-androstene-3,17-dione to testosterone. Mutations in the HSD17B3 Gene causing 17β-HSD3 deficiency are responsible for a rare recessive form of 46, XY Disorders of Sex Development (46, XY DSD). We report novel cases of Tunisian patients with 17β-HSD3 deficiency due to previously reported mutations, i.e. p.C206X and p.G133R, as well as a case with the novel compound heterozygous mutations p.C206X and p.Q176P. Moreover, the previously reported polymorphism p.G289S was identified in a heterozygous state in combination with a novel non-coding variant c.54G>T, also in a heterozygous state, in a male patient presenting with micropenis and low testosterone levels. The identification of four different mutations in a cohort of eight patients confirms the Generally observed Genetic heteroGeneity of 17β-HSD3 deficiency. Nevertheless, analysis of DNA from 272 randomly selected healthy controls from the same geographic area (region of Sfax) revealed a high carrier frequency for the p.C206X mutation of approximately 1 in 40. Genotype reconstruction of the affected pedigree members revealed that all p.C206X mutation carriers harbored the same haplotype, indicating inheritance of the mutation from a common ancestor. Thus, the identification of a founder effect and the elevated carrier frequency of the p.C206X mutation emphasize the importance to consider this mutation in the diagnosis and Genetic counseling of affected 17β-HSD3 deficiency pedigrees in Tunisia.
-
Biochemical analyses and molecular modeling explain the functional loss of 17β-hydroxysteroid dehydrogenase 3 mutant G133R in three Tunisian patients with 46, XY Disorders of Sex Development.
The Journal of steroid biochemistry and molecular biology, 2015Co-Authors: Roger T. Engeli, Bochra Ben Rhouma, Neila Belguith, Maria Tsachaki, Christoph P. Sager, Leila Keskes, Julia Birk, Faiza Fakhfakh, Alex OdermattAbstract:Mutations in the HSD17B3 Gene resulting in 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) deficiency cause 46, XY Disorders of Sex Development (46, XY DSD). Approximately 40 different mutations in HSD17B3 have been reported; only few mutant enzymes have been mechanistically investigated. Here, we report novel compound heterozygous mutations in HSD17B3, composed of the nonsense mutation C206X and the missense mutation G133R, in three Tunisian patients from two non-consanguineous families. Mutants C206X and G133R were constructed by site-directed mutaGenesis and expressed in HEK-293 cells. The truncated C206X enzyme, lacking part of the substrate binding pocket, was moderately expressed and completely lost its enzymatic activity. Wild-type 17β-HSD3 and mutant G133R showed comparable expression levels and intracellular localization. The conversion of Δ4-androstene-3,17-dione (androstenedione) to testosterone was almost completely abolished for mutant G133R compared with wild-type 17β-HSD3. To obtain further mechanistic insight, G133 was mutated to alanine, phenylalanine and glutamine. G133Q and G133F were almost completely inactive, whereas G133A displayed about 70% of wild-type activity. Sequence analysis revealed that G133 on 17β-HSD3 is located in a motif highly conserved in 17β-HSDs and other short-chain dehydrogenase/reductase (SDR) enzymes. A homology model of 17β-HSD3 predicted that arginine or any other bulky residue at position 133 causes steric hindrance of cofactor NADPH binding, whereas substrate binding seems to be unaffected. The results indicate an essential role of G133 in the arrangement of the cofactor binding pocket, thus explaining the loss-of-function of 17β-HSD3 mutant G133R in the patients investigated.
-
A Novel Nonsense Mutation in HSD17B3 Gene in a Tunisian Patient with Sexual Ambiguity
The journal of sexual medicine, 2012Co-Authors: Bochra Ben Rhouma, Neila Belguith, Mouna Mnif, Thouraya Kamoun, Nadia Charfi, Kamoun, Fatma Abdelhedi, Mongia Hachicha, Hassen Kamoun, Mohamed AbidAbstract:ABSTRACT Introduction 17β‐hydroxysteroid dehydrogenase type 3 (HSD17B3) isoenzyme is present almost exclusively in the testes and converts delta 4 androstenedione to testosterone. Mutations in the HSD17B3 Gene cause HSD17B3 deficiency and result in 46,XY Disorders of Sex Development (46,XY DSD). Aim This study aimed to present the clinical and biochemical features of a Tunisian patient who presented a sexual ambiguity orienting to HSD17B3 deficiency and to search for a mutation in the HSD17B3 Gene by DNA sequencing. Methods Polymerase chain reaction (PCR) amplification and subsequent sequencing of all the coding exons of HSD17B3 Gene were performed on genomic DNA from the patient, her family, and 50 controls. Results Genetic mutation analysis of the HSD17B3 Gene revealed the presence of a novel homozygous nonsense mutation in the exon 9 (c.618 C > A) leading to the substitution p.C206X. The mutation p.C206X in the coding exons supports the hypothesis of HSD17B3 deficiency in our patient. Conclusion The patient described in this study represented a new case of a rare form of 46,XY DSD, associated to a novel Gene mutation of HSD17B3 Gene. The screening of this mutation is useful for confirming the diagnosis of HSD17B3 deficiency and for prenatal diagnosis. Ben Rhouma B, Belguith N, Mnif MF, Kamoun T, Charfi N, Kamoun M, Abdelhedi F, Hachicha M, Kamoun H, Abid M, and Fakhfakh F. A novel nonsense mutation in HSD17B3 Gene in a Tunisian patient with sexual ambiguity. J Sex Med 2013;10:2586–2589.
Bochra Ben Rhouma - One of the best experts on this subject based on the ideXlab platform.
-
Novel cases of Tunisian patients with mutations in the Gene encoding 17β-hydroxysteroid dehydrogenase type 3 and a founder effect.
The Journal of steroid biochemistry and molecular biology, 2016Co-Authors: Bochra Ben Rhouma, Hassen Kamoun, Roger T. Engeli, Alex Odermatt, Fakhri Kallabi, Nadia Mahfoudh, Afif Ben Mahmoud, Leila Keskes, Neila BelguithAbstract:17β-Hydroxysteroid dehydrogenase type 3 (17β-HSD3) is expressed almost exclusively in the testis and converts Δ4-androstene-3,17-dione to testosterone. Mutations in the HSD17B3 Gene causing 17β-HSD3 deficiency are responsible for a rare recessive form of 46, XY Disorders of Sex Development (46, XY DSD). We report novel cases of Tunisian patients with 17β-HSD3 deficiency due to previously reported mutations, i.e. p.C206X and p.G133R, as well as a case with the novel compound heterozygous mutations p.C206X and p.Q176P. Moreover, the previously reported polymorphism p.G289S was identified in a heterozygous state in combination with a novel non-coding variant c.54G>T, also in a heterozygous state, in a male patient presenting with micropenis and low testosterone levels. The identification of four different mutations in a cohort of eight patients confirms the Generally observed Genetic heteroGeneity of 17β-HSD3 deficiency. Nevertheless, analysis of DNA from 272 randomly selected healthy controls from the same geographic area (region of Sfax) revealed a high carrier frequency for the p.C206X mutation of approximately 1 in 40. Genotype reconstruction of the affected pedigree members revealed that all p.C206X mutation carriers harbored the same haplotype, indicating inheritance of the mutation from a common ancestor. Thus, the identification of a founder effect and the elevated carrier frequency of the p.C206X mutation emphasize the importance to consider this mutation in the diagnosis and Genetic counseling of affected 17β-HSD3 deficiency pedigrees in Tunisia.
-
Biochemical analyses and molecular modeling explain the functional loss of 17β-hydroxysteroid dehydrogenase 3 mutant G133R in three Tunisian patients with 46, XY Disorders of Sex Development.
The Journal of steroid biochemistry and molecular biology, 2015Co-Authors: Roger T. Engeli, Bochra Ben Rhouma, Neila Belguith, Maria Tsachaki, Christoph P. Sager, Leila Keskes, Julia Birk, Faiza Fakhfakh, Alex OdermattAbstract:Mutations in the HSD17B3 Gene resulting in 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) deficiency cause 46, XY Disorders of Sex Development (46, XY DSD). Approximately 40 different mutations in HSD17B3 have been reported; only few mutant enzymes have been mechanistically investigated. Here, we report novel compound heterozygous mutations in HSD17B3, composed of the nonsense mutation C206X and the missense mutation G133R, in three Tunisian patients from two non-consanguineous families. Mutants C206X and G133R were constructed by site-directed mutaGenesis and expressed in HEK-293 cells. The truncated C206X enzyme, lacking part of the substrate binding pocket, was moderately expressed and completely lost its enzymatic activity. Wild-type 17β-HSD3 and mutant G133R showed comparable expression levels and intracellular localization. The conversion of Δ4-androstene-3,17-dione (androstenedione) to testosterone was almost completely abolished for mutant G133R compared with wild-type 17β-HSD3. To obtain further mechanistic insight, G133 was mutated to alanine, phenylalanine and glutamine. G133Q and G133F were almost completely inactive, whereas G133A displayed about 70% of wild-type activity. Sequence analysis revealed that G133 on 17β-HSD3 is located in a motif highly conserved in 17β-HSDs and other short-chain dehydrogenase/reductase (SDR) enzymes. A homology model of 17β-HSD3 predicted that arginine or any other bulky residue at position 133 causes steric hindrance of cofactor NADPH binding, whereas substrate binding seems to be unaffected. The results indicate an essential role of G133 in the arrangement of the cofactor binding pocket, thus explaining the loss-of-function of 17β-HSD3 mutant G133R in the patients investigated.
-
A Novel Nonsense Mutation in HSD17B3 Gene in a Tunisian Patient with Sexual Ambiguity
The journal of sexual medicine, 2012Co-Authors: Bochra Ben Rhouma, Neila Belguith, Mouna Mnif, Thouraya Kamoun, Nadia Charfi, Kamoun, Fatma Abdelhedi, Mongia Hachicha, Hassen Kamoun, Mohamed AbidAbstract:ABSTRACT Introduction 17β‐hydroxysteroid dehydrogenase type 3 (HSD17B3) isoenzyme is present almost exclusively in the testes and converts delta 4 androstenedione to testosterone. Mutations in the HSD17B3 Gene cause HSD17B3 deficiency and result in 46,XY Disorders of Sex Development (46,XY DSD). Aim This study aimed to present the clinical and biochemical features of a Tunisian patient who presented a sexual ambiguity orienting to HSD17B3 deficiency and to search for a mutation in the HSD17B3 Gene by DNA sequencing. Methods Polymerase chain reaction (PCR) amplification and subsequent sequencing of all the coding exons of HSD17B3 Gene were performed on genomic DNA from the patient, her family, and 50 controls. Results Genetic mutation analysis of the HSD17B3 Gene revealed the presence of a novel homozygous nonsense mutation in the exon 9 (c.618 C > A) leading to the substitution p.C206X. The mutation p.C206X in the coding exons supports the hypothesis of HSD17B3 deficiency in our patient. Conclusion The patient described in this study represented a new case of a rare form of 46,XY DSD, associated to a novel Gene mutation of HSD17B3 Gene. The screening of this mutation is useful for confirming the diagnosis of HSD17B3 deficiency and for prenatal diagnosis. Ben Rhouma B, Belguith N, Mnif MF, Kamoun T, Charfi N, Kamoun M, Abdelhedi F, Hachicha M, Kamoun H, Abid M, and Fakhfakh F. A novel nonsense mutation in HSD17B3 Gene in a Tunisian patient with sexual ambiguity. J Sex Med 2013;10:2586–2589.