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Yaron S Rabinowitz - One of the best experts on this subject based on the ideXlab platform.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:PURPOSE. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families. METHODS. Association results were analyzed of single-nucleotide polymorphisms (SNPs) in the LOX gene from a GenomeWide Association Study (GWAS) investigation in two independent panels of patients with Keratoconus and controls and in Keratoconus families. RESULTS. Evidence of association was found at SNPs rs10519694 and rs2956540 located in intron 4 of LOX in the GWAS discovery case-control panel with P values of 2.3 3 10 � 3 and 7 3 10 � 3 , respectively. The same two SNPs were found to be associated with Keratoconus by family-based association testing with P values of 2.7 3 10 � 3 and 7.7 3 10 � 4 , respectively. Meta P values of 4.0 3 10 � 5 and 4.0 3 10 � 7 were calculated for SNPs rs10519694 and rs2956540 by analyzing case-control and family samples simultaneously. Sequencing of LOX exons in a subset of Keratoconus patients identified two polymorphisms, rs1800449 and rs2288393, located in LOX transcripts I and II, associated with Keratoconus in case-control and family samples with a meta P value of 0.02.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:Purpose. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families.
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Keratoconus classification scheme based on videokeratography and clinical signs
Journal of Cataract and Refractive Surgery, 2009Co-Authors: Huiying Yang, Yaron S RabinowitzAbstract:Purpose To determine in a longitudinal study whether there is correlation between videokeratography and clinical signs of Keratoconus that might be useful to practicing clinicians. Setting Cornea-Genetic Eye Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA. Methods Eyes grouped as Keratoconus, early Keratoconus, Keratoconus suspect, or normal based on clinical signs and videokeratography were examined at baseline and followed for 1 to 8 years. Differences in quantitative videokeratography indices and the progression rate were evaluated. The quantitative indices were central keratometry (K), the inferior–superior (I–S) value, and the Keratoconus percentage index (KISA). Discriminant analysis was used to estimate the classification rate using the indices. Results There were significant differences at baseline between the normal, Keratoconus-suspect, and early Keratoconus groups in all indices; the respective means were central K: 44.17 D, 45.13 D, and 45.97 D; I–S: 0.57, 1.20, and 4.44; log(KISA): 2.49, 2.94, and 5.71 (all P Conclusions Cross-sectional and longitudinal data showed significant differences between groups in the 3 indices. Use of this classification scheme might form a basis for detecting subclinical Keratoconus.
David Huang - One of the best experts on this subject based on the ideXlab platform.
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differentiating Keratoconus and corneal warpage by analyzing focal change patterns in corneal topography pachymetry and epithelial thickness maps
Investigative Ophthalmology & Visual Science, 2016Co-Authors: Maolong Tang, Winston Chamberlain, Derek J Louie, Julie M Schallhorn, David HuangAbstract:To differentiate between Keratoconus and contact lens-related corneal warpage by combining focal change patterns in anterior corneal topography, pachymetry, and epithelial thickness maps.Pachymetry and epithelial thickness maps of normal, Keratoconus, and warpage, and forme fruste Keratoconus (FFK) eyes were obtained from a Fourier-domain optical coherence tomography (OCT). Epithelial pattern standard deviation (PSD) was calculated and combined with two novel indices, the Warpage Index and the Anterior Ectasia Index, to differentiate between normal, Keratoconus, and warpage eyes. The values of the three parameters were compared between groups.The study included 22 normal, 31 keratoconic, 11 warpage, and 8 FFK eyes. The epithelial PSD was normal ( 0.041) for 100% of keratoconic eyes, 81.8% of warpage eyes, and 87.5% of FFK eyes. The Anterior Ectasia Index of normal eyes (1.66 ± 0.74) was significantly lower than that for the Keratoconus eyes (17.5 ± 7.17), the warpage eyes (2.98 ± 1.69), and the FFK eyes (6.95 ± 5.86). The Warpage Index was positive in all warpage eyes and negative for all keratoconic and FFK eyes except three wearing rigid gas-permeable contact lens.The epithelial PSD can distinguish normal from Keratoconus or warpage, but does not distinguish between these two conditions. The Anterior Ectasia Index is abnormal in Keratoconus but not warpage. The Warpage Index is positive for warpage and negative for Keratoconus, except in cases where Keratoconus and warpage coexist. Together, the three parameters are strong tripartite discriminators of normal, Keratoconus, and warpage.
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differentiating Keratoconus and corneal warpage by analyzing focal change patterns in corneal topography pachymetry and epithelial thickness maps
Investigative Ophthalmology & Visual Science, 2016Co-Authors: Maolong Tang, Winston Chamberlain, Derek J Louie, Julie M Schallhorn, David HuangAbstract:Author(s): Tang, Maolong; Li, Yan; Chamberlain, Winston; Louie, Derek J; Schallhorn, Julie M; Huang, David | Abstract: PurposeTo differentiate between Keratoconus and contact lens-related corneal warpage by combining focal change patterns in anterior corneal topography, pachymetry, and epithelial thickness maps.MethodsPachymetry and epithelial thickness maps of normal, Keratoconus, and warpage, and forme fruste Keratoconus (FFK) eyes were obtained from a Fourier-domain optical coherence tomography (OCT). Epithelial pattern standard deviation (PSD) was calculated and combined with two novel indices, the Warpage Index and the Anterior Ectasia Index, to differentiate between normal, Keratoconus, and warpage eyes. The values of the three parameters were compared between groups.ResultsThe study included 22 normal, 31 keratoconic, 11 warpage, and 8 FFK eyes. The epithelial PSD was normal (l 0.041) for 100% normal eyes and abnormal (g 0.041) for 100% of keratoconic eyes, 81.8% of warpage eyes, and 87.5% of FFK eyes. The Anterior Ectasia Index of normal eyes (1.66 ± 0.74) was significantly lower than that for the Keratoconus eyes (17.5 ± 7.17), the warpage eyes (2.98 ± 1.69), and the FFK eyes (6.95 ± 5.86). The Warpage Index was positive in all warpage eyes and negative for all keratoconic and FFK eyes except three wearing rigid gas-permeable contact lens.ConclusionsThe epithelial PSD can distinguish normal from Keratoconus or warpage, but does not distinguish between these two conditions. The Anterior Ectasia Index is abnormal in Keratoconus but not warpage. The Warpage Index is positive for warpage and negative for Keratoconus, except in cases where Keratoconus and warpage coexist. Together, the three parameters are strong tripartite discriminators of normal, Keratoconus, and warpage.
Sudha K Iyengar - One of the best experts on this subject based on the ideXlab platform.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:PURPOSE. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families. METHODS. Association results were analyzed of single-nucleotide polymorphisms (SNPs) in the LOX gene from a GenomeWide Association Study (GWAS) investigation in two independent panels of patients with Keratoconus and controls and in Keratoconus families. RESULTS. Evidence of association was found at SNPs rs10519694 and rs2956540 located in intron 4 of LOX in the GWAS discovery case-control panel with P values of 2.3 3 10 � 3 and 7 3 10 � 3 , respectively. The same two SNPs were found to be associated with Keratoconus by family-based association testing with P values of 2.7 3 10 � 3 and 7.7 3 10 � 4 , respectively. Meta P values of 4.0 3 10 � 5 and 4.0 3 10 � 7 were calculated for SNPs rs10519694 and rs2956540 by analyzing case-control and family samples simultaneously. Sequencing of LOX exons in a subset of Keratoconus patients identified two polymorphisms, rs1800449 and rs2288393, located in LOX transcripts I and II, associated with Keratoconus in case-control and family samples with a meta P value of 0.02.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:Purpose. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families.
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a new method for grading the severity of Keratoconus the Keratoconus severity score kss
Cornea, 2006Co-Authors: Timothy T Mcmahon, Loretta B Szczotkaflynn, Joseph T Barr, Robert J Anderson, M Slaughter, Jonathan H Lass, Sudha K IyengarAbstract:PURPOSE: To define a new method for grading severity of Keratoconus, the Keratoconus Severity Score (KSS). METHODS: A rationale for grading Keratoconus severity was developed using common clinical markers plus 2 corneal topographic indices, creating a 0 to 5 severity score. An initial test set of 1012 eyes, including normal eyes, eyes with abnormal corneal and topographic findings but not Keratoconus, and eyes with Keratoconus having a wide range of severity, was used to determine cutpoints for the KSS. Validation set 1, comprising data from 128 eyes, was assigned a KSS and compared with a clinician's ranking of severity termed the "gold standard" to determine if the scale fairly represented how a clinician would grade disease severity. kappa statistics, sensitivity, and specificity were calculated. A program was developed to automate the determination of the score. This was tested against a manual assignment of KSS in 2121 (validation set 2) eyes from the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study, as well as normal eyes and abnormal eyes without Keratoconus. Ten percent of eyes underwent repeat manual assignment of KSS to determine the variability of manual assignment of a score. RESULTS: From initial assessments, the KSS used 2 corneal topography indices: average corneal power and root mean square (RMS) error for higher-order Zernike terms derived from the first corneal surface wavefront. Clinical signs including Vogt striae, Fleischer rings, and corneal scarring were also included. Last, a manual interpretation of the map pattern was included. Validation set 1 yielded a kappa statistic of 0.904, with sensitivities ranging from 0.64 to 1.00 and specificities ranging from 0.93 to 0.98. The sensitivity and specificity for determining nonKeratoconus from Keratoconus were both 1.00. Validation set 2 showed kappa statistics of 0.94 and 0.95 for right and left eyes, respectively. Test-retest analysis yielded kappa statistics of 0.84 and 0.83 for right and left eyes, respectively. CONCLUSION: A simple and reliable grading system for Keratoconus was developed that can be largely automated. Such a grading scheme could be useful in genetic studies for a complex trait such as Keratoconus requiring a quantitative measure of disease presence and severity.
Loretta B Szczotkaflynn - One of the best experts on this subject based on the ideXlab platform.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:PURPOSE. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families. METHODS. Association results were analyzed of single-nucleotide polymorphisms (SNPs) in the LOX gene from a GenomeWide Association Study (GWAS) investigation in two independent panels of patients with Keratoconus and controls and in Keratoconus families. RESULTS. Evidence of association was found at SNPs rs10519694 and rs2956540 located in intron 4 of LOX in the GWAS discovery case-control panel with P values of 2.3 3 10 � 3 and 7 3 10 � 3 , respectively. The same two SNPs were found to be associated with Keratoconus by family-based association testing with P values of 2.7 3 10 � 3 and 7.7 3 10 � 4 , respectively. Meta P values of 4.0 3 10 � 5 and 4.0 3 10 � 7 were calculated for SNPs rs10519694 and rs2956540 by analyzing case-control and family samples simultaneously. Sequencing of LOX exons in a subset of Keratoconus patients identified two polymorphisms, rs1800449 and rs2288393, located in LOX transcripts I and II, associated with Keratoconus in case-control and family samples with a meta P value of 0.02.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:Purpose. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families.
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a new method for grading the severity of Keratoconus the Keratoconus severity score kss
Cornea, 2006Co-Authors: Timothy T Mcmahon, Loretta B Szczotkaflynn, Joseph T Barr, Robert J Anderson, M Slaughter, Jonathan H Lass, Sudha K IyengarAbstract:PURPOSE: To define a new method for grading severity of Keratoconus, the Keratoconus Severity Score (KSS). METHODS: A rationale for grading Keratoconus severity was developed using common clinical markers plus 2 corneal topographic indices, creating a 0 to 5 severity score. An initial test set of 1012 eyes, including normal eyes, eyes with abnormal corneal and topographic findings but not Keratoconus, and eyes with Keratoconus having a wide range of severity, was used to determine cutpoints for the KSS. Validation set 1, comprising data from 128 eyes, was assigned a KSS and compared with a clinician's ranking of severity termed the "gold standard" to determine if the scale fairly represented how a clinician would grade disease severity. kappa statistics, sensitivity, and specificity were calculated. A program was developed to automate the determination of the score. This was tested against a manual assignment of KSS in 2121 (validation set 2) eyes from the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study, as well as normal eyes and abnormal eyes without Keratoconus. Ten percent of eyes underwent repeat manual assignment of KSS to determine the variability of manual assignment of a score. RESULTS: From initial assessments, the KSS used 2 corneal topography indices: average corneal power and root mean square (RMS) error for higher-order Zernike terms derived from the first corneal surface wavefront. Clinical signs including Vogt striae, Fleischer rings, and corneal scarring were also included. Last, a manual interpretation of the map pattern was included. Validation set 1 yielded a kappa statistic of 0.904, with sensitivities ranging from 0.64 to 1.00 and specificities ranging from 0.93 to 0.98. The sensitivity and specificity for determining nonKeratoconus from Keratoconus were both 1.00. Validation set 2 showed kappa statistics of 0.94 and 0.95 for right and left eyes, respectively. Test-retest analysis yielded kappa statistics of 0.84 and 0.83 for right and left eyes, respectively. CONCLUSION: A simple and reliable grading system for Keratoconus was developed that can be largely automated. Such a grading scheme could be useful in genetic studies for a complex trait such as Keratoconus requiring a quantitative measure of disease presence and severity.
Yelena Bykhovskaya - One of the best experts on this subject based on the ideXlab platform.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:Purpose. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families.
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variation in the lysyl oxidase lox gene is associated with Keratoconus in family based and case control studies
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Yelena Bykhovskaya, Loretta B Szczotkaflynn, Sudha K Iyengar, Irina Epifantseva, Talin Haritunians, David S Siscovick, Anthony J Aldave, Kent D Taylor, Jerome I Rotter, Yaron S RabinowitzAbstract:PURPOSE. Keratoconus is a bilateral noninflammatory progressive corneal disorder with complex genetic inheritance and a common cause for cornea transplantation in young adults. A genomewide linkage scan in Keratoconus families identified a locus at 5q23.2, overlapping the gene coding for the lysyl oxidase (LOX). LOX encodes an enzyme responsible for collagen cross-linking in a variety of tissues including the cornea. Corneal collagen cross-linking with long-wave ultraviolet light and riboflavin is a promising new treatment for Keratoconus. To determine whether LOX is a genetic determinant of the pathogenesis of Keratoconus, we analyzed association results of LOX polymorphisms in two independent case-control samples and in Keratoconus families. METHODS. Association results were analyzed of single-nucleotide polymorphisms (SNPs) in the LOX gene from a GenomeWide Association Study (GWAS) investigation in two independent panels of patients with Keratoconus and controls and in Keratoconus families. RESULTS. Evidence of association was found at SNPs rs10519694 and rs2956540 located in intron 4 of LOX in the GWAS discovery case-control panel with P values of 2.3 3 10 � 3 and 7 3 10 � 3 , respectively. The same two SNPs were found to be associated with Keratoconus by family-based association testing with P values of 2.7 3 10 � 3 and 7.7 3 10 � 4 , respectively. Meta P values of 4.0 3 10 � 5 and 4.0 3 10 � 7 were calculated for SNPs rs10519694 and rs2956540 by analyzing case-control and family samples simultaneously. Sequencing of LOX exons in a subset of Keratoconus patients identified two polymorphisms, rs1800449 and rs2288393, located in LOX transcripts I and II, associated with Keratoconus in case-control and family samples with a meta P value of 0.02.
