Novel and known variants in GJA3 and LIM2 in congenital cataract families from North India.

BACKGROUND: To identify the underlying genetic defects in autosomal dominant (ADCC) and autosomal recessive (ARCC) congenital cataract families from North India. METHODS: Detailed family histories were collected, pedigrees drawn followed by slit-lamp examination and lens photography. Mutation screening was performed using Sanger sequencing in the known candidate genes for crystallins, connexins, and membrane proteins. The pathogenicity of identified variants was assessed bioinformatically. RESULTS: In two ADCC families (CC-281 and CC-3015) with posterior lenticonus cataract, a novel change c.263C > T (p.P88L) in GJA3 in CC-281 family and a previously reported substitution c.388C > T (p.R130C) in LIM2 in CC-3015 family was observed. In an ARCC family (CC-3005) having central pulverulent cataract, a novel frameshift deletion (c.764delT;p.L255R46fs) in GJA3 was detected. The observed variants segregated completely with phenotypes in the affected members and were neither present in unaffected family members nor in the ethnically matched 150 controls (tested for two novel variants), hence excluding these as polymorphisms. CONCLUSIONS: Present study identified two novel mutations i.e., c.263C > T;p.P88L and c.764delT;p.L255R46fs in GJA3 in an ADCC and an ARCC family having posterior lenticonus and central pulverulent cataract, respectively. In another ADCC family with posterior lenticonus cataract, a previously reported mutation c.388C > T;p.R130C in LIM2 was observed. R130 may be a mutation hotspot as previously ADCC families from different ethnicities (UK/Czechia, China, Spain, Japan) also harbored the same substitution, however, with different phenotypes i.e., nuclear pulverulent, membranous, nuclear, lamellar, and sutural/lamellar. Findings in present study thus expand the mutation spectrum and phenotypic heterogeneity linked with GJA3 and LIM2.

Mutation screening in autosomal dominant congenital cataract families from North India.

Congenital cataract an opacity of the eye lens is present at birth and results in visual impairment during early childhood. If left untreated, it can lead to permanent blindness. Its prevalence is ten times higher in developing countries like India. Thus, we aimed to investigate the underlying genetic defects in three autosomal dominant congenital cataract (ADCC) families from North India. Detailed family histories were collected, pedigrees drawn followed by slit-lamp examination and lens photography. Mutation screening was performed in the candidate genes for crystallins, connexins, and membrane proteins by Sanger sequencing. Pathogenicity of novel variant was assessed bioinformatically. In an ADCC (CC-3006) family with bilateral membranous cataract and microcornea, a novel change (c.1114C>T;p.P372S) in GJA3 has been detected. In other two ADCC families affected with subcapsular (CC-286) and shrunken membranous hypermature cataract (CC-3014), a nonsense mutation (c.463C>T;p.Q155X) in CRYßB2 and a frameshift deletion (c.590_591delAG;p.E197VfsX22) in CRYßA1/A3 respectively, are observed. These variants segregated completely with the phenotypes in respective families and were absent in their unaffected family members and unrelated controls (tested for novel variant in GJA3). Earlier p.Q155X (CRYßB2) and p.E197VfsX22 (CRYßA1/A3) are reported with entirely different phenotypes. Thus, findings in present study expand the mutation spectrum and phenotypic heterogeneity linked with GJA3, CRYßB2, and CRYßA1/A3 for congenital cataracts. Identifying underlying genetic defects is essential for disease management and appropriate genetic counseling.

A Bidirectional Mendelian Randomization Study to evaluate the causal role of reduced blood vitamin D levels with type 2 diabetes risk in South Asians and Europeans.

CONTEXT: Multiple observational studies have reported an inverse relationship between 25-hydroxyvitamin D concentrations (25(OH)D) and type 2 diabetes (T2D). However, the results of short- and long-term interventional trials concerning the relationship between 25(OH)D and T2D risk have been inconsistent. OBJECTIVES AND METHODS: To evaluate the causal role of reduced blood 25(OH)D in T2D, here we have performed a bidirectional Mendelian randomization study using 59,890 individuals (5,862 T2D cases and 54,028 controls) from European and Asian Indian ancestries. We used six known SNPs, including three T2D SNPs and three vitamin D pathway SNPs, as a genetic instrument to evaluate the causality and direction of the association between T2D and circulating 25(OH)D concentration. RESULTS: Results of the combined meta-analysis of eight participating studies showed that a composite score of three T2D SNPs would significantly increase T2D risk by an odds ratio (OR) of 1.24, p = 1.82 × 10-32; Z score 11.86, which, however, had no significant association with 25(OH)D status (Beta -0.02nmol/L ± SE 0.01nmol/L; p = 0.83; Z score -0.21). Likewise, the genetically instrumented composite score of 25(OH)D lowering alleles significantly decreased 25(OH)D concentrations (-2.1nmol/L ± SE 0.1nmol/L, p = 7.92 × 10-78; Z score -18.68) but was not associated with increased risk for T2D (OR 1.00, p = 0.12; Z score 1.54). However, using 25(OH)D synthesis SNP (DHCR7; rs12785878) as an individual genetic instrument, a per allele reduction of 25(OH)D concentration (-4.2nmol/L ± SE 0.3nmol/L) was predicted to increase T2D risk by 5%, p = 0.004; Z score 2.84. This effect, however, was not seen in other 25(OH)D SNPs (GC rs2282679, CYP2R1 rs12794714) when used as an individual instrument. CONCLUSION: Our new data on this bidirectional Mendelian randomization study suggests that genetically instrumented T2D risk does not cause changes in 25(OH)D levels. However, genetically regulated 25(OH)D deficiency due to vitamin D synthesis gene (DHCR7) may influence the risk of T2D.

APOC3 genetic variation, serum triglycerides, and risk of coronary artery disease in Asian Indians, Europeans, and other ethnic groups.

BACKGROUND: Hypertriglyceridemia has emerged as a critical coronary artery disease (CAD) risk factor. Rare loss-of-function (LoF) variants in apolipoprotein C-III have been reported to reduce triglycerides (TG) and are cardioprotective in American Indians and Europeans. However, there is a lack of data in other Europeans and non-Europeans. Also, whether genetically increased plasma TG due to ApoC-III is causally associated with increased CAD risk is still unclear and inconsistent. The objectives of this study were to verify the cardioprotective role of earlier reported six LoF variants of APOC3 in South Asians and other multi-ethnic cohorts and to evaluate the causal association of TG raising common variants for increasing CAD risk. METHODS: We performed gene-centric and Mendelian randomization analyses and evaluated the role of genetic variation encompassing APOC3 for affecting circulating TG and the risk for developing CAD. RESULTS: One rare LoF variant (rs138326449) with a 37% reduction in TG was associated with lowered risk for CAD in Europeans (p = 0.007), but we could not confirm this association in Asian Indians (p = 0.641). Our data could not validate the cardioprotective role of other five LoF variants analysed. A common variant rs5128 in the APOC3 was strongly associated with elevated TG levels showing a p-value 2.8 × 10- 424. Measures of plasma ApoC-III in a small subset of Sikhs revealed a 37% increase in ApoC-III concentrations among homozygous mutant carriers than the wild-type carriers of rs5128. A genetically instrumented per 1SD increment of plasma TG level of 15 mg/dL would cause a mild increase (3%) in the risk for CAD (p = 0.042). CONCLUSIONS: Our results highlight the challenges of inclusion of rare variant information in clinical risk assessment and the generalizability of implementation of ApoC-III inhibition for treating atherosclerotic disease. More studies would be needed to confirm whether genetically raised TG and ApoC-III concentrations would increase CAD risk.

Polygenic Risk Score Assessment for Coronary Artery Disease in Asian Indians.

We evaluated the performance of various polygenic risk score (PRS) models derived from European (EU), South Asian (SA), and Punjabi Asian Indians (AI) studies on 13,974 subjects from AI ancestry. While all models successfully predicted Coronary artery disease (CAD) risk, the AI, SA, and EU + AI were superior predictors and more transportable than the EU model; the predictive performance in training and test sets was 18% and 22% higher in AI and EU + AI models, respectively than in EU. Comparing individuals with extreme PRS quartiles, the AI and EU + AI captured individuals with high CAD risk showed 2.6 to 4.6 times higher efficiency than the EU. Interestingly, including the clinical risk score did not significantly change the performance of any genetic model. The enrichment of diversity variants in EU PRS improves risk prediction and transportability. Establishing population-specific normative and risk factors and inclusion into genetic models would refine the risk stratification and improve the clinical utility of CAD PRS.

Assessing the prediction of type 2 diabetes risk using polygenic and clinical risk scores in South Asian study populations.

Background: Genome-wide polygenic risk scores (PRS) have shown high specificity and sensitivity in predicting type 2 diabetes (T2D) risk in Europeans. However, the PRS-driven information and its clinical significance in non-Europeans are underrepresented. We examined the predictive efficacy and transferability of PRS models using variant information derived from genome-wide studies of Asian Indians (AIs) (PRSAI) and Europeans (PRSEU) using 13,974 AI individuals. Methods: Weighted PRS models were constructed and analyzed on 4602 individuals from the Asian Indian Diabetes Heart Study/Sikh Diabetes Study (AIDHS/SDS) as discovery/training and test/validation datasets. The results were further replicated in 9372 South Asian individuals from UK Biobank (UKBB). We also assessed the performance of each PRS model by combining data of the clinical risk score (CRS). Results: Both genetic models (PRSAI and PRSEU) successfully predicted the T2D risk. However, the PRSAI revealed 13.2% odds ratio (OR) 1.80 [95% confidence interval (CI) 1.63-1.97; p = 1.6 × 10-152] and 12.2% OR 1.38 (95% CI 1.30-1.46; p = 7.1 × 10-237) superior performance in AIDHS/SDS and UKBB validation sets, respectively. Comparing individuals of extreme PRS (ninth decile) with the average PRS (fifth decile), PRSAI showed about two-fold OR 20.73 (95% CI 10.27-41.83; p = 2.7 × 10-17) and 1.4-fold OR 3.19 (95% CI 2.51-4.06; p = 4.8 × 10-21) higher predictability to identify subgroups with higher genetic risk than the PRSEU. Combining PRS and CRS improved the area under the curve from 0.74 to 0.79 in PRSAI and 0.72 to 0.75 in PRSEU. Conclusion: Our data suggest the need for extending genetic and clinical studies in varied ethnic groups to exploit the full clinical potential of PRS as a risk prediction tool in diverse study populations.

A novel 7 bp deletion in PRPF31 associated with autosomal dominant retinitis pigmentosa with incomplete penetrance in an Indian family.

To localize and identify the gene linked with non-syndromic autosomal dominant retinitis pigmentosa (adRP) with high but not complete penetrance in an Indian family. A detailed family history and clinical data were recorded. A genome-wide scan by 2-point linkage analysis using nearly 400 fluorescently labeled microsatellite markers in combination with multipoint lod score and haplotype analysis was carried out. Mutation screening was performed in the candidate gene by bidirectional sequence analysis of the amplified products. A maximum 2-point lod score of 3.553 at theta = 0.0 was obtained with marker D19S572. Haplotype analysis placed the RP locus distal to marker D19S572, in close proximity to the gene for pre-mRNA processing factor 31 (PRPF31) at 19q13.42. Mutation screening in all 14 exonic regions and adjacent flanking intronic sequences of PRPF31 revealed a novel 7 bp deletion, c.59_65del7 (p.Gly20AlafsX43), in the first coding exon of PRPF31. This leads to a premature termination codon (PTC) in the next exon, 43 amino acids downstream. The observed 7 bp deletion in PRPF31 was identified in all the tested 10 affected members and in an unaffected individual, consistent with a high, but not the complete penetrance of c.59_65del7 (p.Gly20AlafsX43). This deletion was not observed in other tested six unaffected family members or in 100 ethnically matched control subjects. The present study describes mapping of a locus for non-syndromic adRP at 19q13.42 (RP11 locus) in a family of Indian origin and identifies a novel deletion, c.59_65del7, in PRPF31 within the mapped interval. Since the mutant PRPF31 is truncated relatively close to the N-terminus of the protein, haploinsufficiency rather than aberrant protein formation is likely to be the underlying mechanism of the disease. The present findings further substantiate the role of PRPF31 that encodes a component of the spliceosome complex in relation to ADRP.

Karyotypic findings in chronic myeloid leukemia cases undergoing treatment.

BACKGROUND: Chronic myeloid leukemia (CML) is a clonal myeloproliferative expansion of primitive hematopoietic progenitor cells. MATERIALS AND METHODS: In the present study, CML samples were collected from various hospitals in Amritsar, Jalandhar and Ludhiana. RESULTS: Chromosomal alterations seen in peripheral blood lymphocytes of these treated and untreated cases of CML were satellite associations, double minutes, random loss, gain of C group chromosomes and presence of marker chromosome. No aberrations were observed in control samples. Karyotypic abnormalities have also been noted in the Ph-negative cells of some patients in disease remission. CONCLUSION: This is a novel phenomenon whose prognostic implications require thorough and systematic evaluation.

Burden of Type 2 Diabetes and Associated Cardiometabolic Traits and Their Heritability Estimates in Endogamous Ethnic Groups of India: Findings From the INDIGENIUS Consortium.

To assess the burden of type 2 diabetes (T2D) and its genetic profile in endogamous populations of India given the paucity of data, we aimed to determine the prevalence of T2D and estimate its heritability using family-based cohorts from three distinct Endogamous Ethnic Groups (EEGs) representing Northern (Rajasthan [Agarwals: AG]) and Southern (Tamil Nadu [Chettiars: CH] and Andhra Pradesh [Reddys: RE]) states of India. For comparison, family-based data collected previously from another North Indian Punjabi Sikh (SI) EEG was used. In addition, we examined various T2D-related cardiometabolic traits and determined their heritabilities. These studies were conducted as part of the Indian Diabetes Genetic Studies in collaboration with US (INDIGENIUS) Consortium. The pedigree, demographic, phenotypic, covariate data and samples were collected from the CH, AG, and RE EEGs. The status of T2D was defined by ADA guidelines (fasting glucose ≥ 126 mg/dl or HbA1c ≥ 6.5% and/or use of diabetes medication/history). The prevalence of T2D in CH (N = 517, families = 21, mean age = 47y, mean BMI = 27), AG (N = 530, Families = 25, mean age = 43y, mean BMI = 27), and RE (N = 500, Families = 22, mean age = 46y, mean BMI = 27) was found to be 33%, 37%, and 36%, respectively, Also, the study participants from these EEGs were found to be at increased cardiometabolic risk (e.g., obesity and prediabetes). Similar characteristics for the SI EEG (N = 1,260, Families = 324, Age = 51y, BMI = 27, T2D = 75%) were obtained previously. We used the variance components approach to carry out genetic analyses after adjusting for covariate effects. The heritability (h2) estimates of T2D in the CH, RE, SI, and AG were found to be 30%, 46%, 54%, and 82% respectively, and statistically significant (P ≤ 0.05). Other T2D related traits (e.g., BMI, lipids, blood pressure) in AG, CH, and RE EEGs exhibited strong additive genetic influences (h2 range: 17% [triglycerides/AG and hs-CRP/RE] - 86% [glucose/non-T2D/AG]). Our findings highlight the high burden of T2D in Indian EEGs with significant and differential additive genetic influences on T2D and related traits.

Novel mutation in the gamma-S crystallin gene causing autosomal dominant cataract.

PURPOSE: To identify the underlying genetic defect in a north Indian family with seven members in three-generations affected with bilateral congenital cataract. METHODS: Detailed family history and clinical data were recorded. Linkage analysis using fluorescently labeled microsatellite markers for the already known candidate gene loci was performed in combination with mutation screening by bidirectional sequencing. RESULTS: Affected individuals had bilateral congenital cataract. Cataract was of opalescent type with the central nuclear region denser than the periphery. Linkage was excluded for the known cataract candidate gene loci at 1p34-36, 1q21-25 (gap junction protein, alpha 8 [GJA8]), 2q33-36 (crystallin, gamma A [CRYGA], crystallin, gamma B [CRYGB], crystallin, gamma C [CRYGC], crystallin, gamma D [CRYGD], crystallin, beta A2 [CRYBA2]), 3q21-22 (beaded filament structural protein 2, phakinin [BFSP2]), 12q12-14 (aquaporin 0 [AQP0]), 13q11-13 (gap junction protein, alpha 3 [GJA3]), 15q21-22, 16q22-23 (v-maf musculoaponeurotic fibrosarcoma oncogene homolog [MAF], heat shock transcription factor 4 [HSF4]), 17q11-12 (crystallin, beta A1 [CRYBA1]), 17q24, 21q22.3 (crystallin, alpha A [CRYAA]), and 22q11.2 (crystallin, beta B1 [CRYBB1], crystallin, beta B2 [CRYBB2], crystallin, beta B3 [CRYBB3], crystallin, beta A4 [CRYBA4]). Crystallin, alpha B (CRYAB) at chromosome 11q23-24 was excluded by sequence analysis. However, sequencing the candidate gene, crystallin, gamma S (CRYGS), at chromosome 3q26.3-qter showed a heterozygous c.176G-->A change that resulted in the replacement of a structurally highly conserved valine by methionine at codon 42 (p.V42M). This sequence change was not observed in unaffected family members or in the 100 ethnically matched controls. CONCLUSIONS: We report a novel missense mutation, p.V42M, in CRYGS associated with bilateral congenital cataract in a family of Indian origin. This is the third report of a mutation in this exceptional member of the beta-/gamma-crystallin superfamily and further substantiates the genetic and clinical heterogeneity of autosomal dominant cataract.

A novel mutation in GJA8 associated with jellyfish-like cataract in a family of Indian origin.

PURPOSE: To identify the underlying genetic defect in a three-generation family with five members affected with dominant bilateral congenital cataract and microcornea. METHODS: Detailed family history and clinical data were recorded. Mutation screening in the candidate genes, CRYAA, CRYBB1, MAF, GJA3, and GJA8, was performed by bidirectional sequencing of the amplified products. RESULTS: Affected individuals had a jellyfish-like cataract in association with microcornea. Sequencing of GJA8 (connexin 50) showed a novel, heterozygous c.134G-->C change that resulted in the substitution of a highly conserved tryptophan by serine (p.W45S). This sequence change segregated completely with the disease phenotype and was not observed in 108 ethnically matched controls (216 chromosomes). However, an identical substitution has previously been described in GJA3 (connexin 46) leading to autosomal dominant nuclear cataract without microcornea. CONCLUSIONS: This is a novel mutation identified in the first transmembrane domain (M1) of GJA8. These findings further expand the mutation spectrum of connexin 50 (Cx50) in association with congenital cataract and microcornea.

A mutation in GJA8 (p.P88Q) is associated with "balloon-like" cataract with Y-sutural opacities in a family of Indian origin.

PURPOSE: To detect the underlying genetic defect in a family with three members in two generations affected with bilateral congenital cataract. METHODS: Detailed family history and clinical data were recorded. Mutation screening in the candidate genes, alphaA-crystallin (CRYAA), betaA1-crystallin (CRYBA1), betaB2-crystallin (CRYBB2), gammaA-gammaD-crystallins (CRYGA, CRYGB, CRYGC, and CRYGD), connexin-46 (GJA3), and connexin-50 (GJA8), was performed by bidirectional sequencing of the amplified products. RESULTS: Affected individuals had "balloon-like" cataract with prominent Y-sutural opacities. Sequencing of the candidate genes showed a heterozygous c.262C>A change in the gene for connexin 50 (GJA8), which is localized at 1q21, that resulted in the replacement of a highly conserved proline by glutamine (p.P88Q). This sequence change was not observed in 96 ethnically matched controls. CONCLUSIONS: We report a p.P88Q mutation in GJA8 associated with Y-sutural cataract in a family of Indian origin. Mutations of the same codon have previously been described in British families with pulverulent cataract, suggesting that modifying factors may determine the type of cataract.

A novel "pearl box" cataract associated with a mutation in the connexin 46 (GJA3) gene.

PURPOSE: To undertake mutation screening in the connexin 46 (GJA3) gene in seven congenital cataract families of Indian origin. METHODS: Seven Indian families with congenital cataract were analyzed by detailed family history and clinical evaluation. Each family had two to five affected members. Mutation screening was carried out in the candidate gene, connexin 46 (GJA3), using bidirectional sequencing of amplified products. Segregation of the observed change with the disease phenotype was further tested by restriction fragment length polymorphism (RFLP). RESULTS: Sequencing of the coding region of GJA3 showed the presence of a novel, heterozygous C260T change in one family (CC-472) who had two affected members. The cataract phenotype gave the appearance like a "pearl box" in these two affected individuals of this family. The observed C260T substitution created a novel restriction enzyme site for NlaIII and resulted in substitution of highly conserved threonine at position 87 by methionine (T87M). NlaIII restriction digestion analysis revealed this nucleotide change was not in unaffected members of this family or in 100 unrelated control subjects (200 chromosomes) with the same ethnic background. CONCLUSIONS: This is a novel mutation identified in the second transmembrane domain of the connexin 46. These findings thus expand the mutation spectrum of the GJA3 in association with congenital cataract.

A novel mutation in the connexin 46 (GJA3) gene associated with autosomal dominant congenital cataract in an Indian family.

PURPOSE: To identify the genetic defect in an autosomal dominant congenital cataract family (ADCC), having 18 individuals in four generations affected with embryonal cataract. METHODS: A genome wide scan using the GeneChip Human Mapping 10K Array, version 2 was performed on DNA samples from eight affected and two unaffected members of an ADCC family having 18 members in four generations affected with embryonal cataract. The region of potential linkage delimited by single nucleotide polymorphic (SNP) markers was analyzed using fluorescently labeled microsatellite markers. Mutation screening was performed in the candidate gene by bidirectional sequencing of amplified products. RESULTS: By whole genome screening linkage in this family, the genetic defect was located to a region of chromosome 13q11 which contains the candidate gene connexin 46 (GJA3) for ADCC. Sequencing of the coding region of GJA3 showed a novel heterozygous 98G>T change resulting in the substitution of highly conserved arginine by leucine at codon 33 (R33L), located in the first transmembrane domain of GJA3. This nucleotide change was not seen in any unaffected members of this family nor in 50 unrelated control subjects. CONCLUSIONS: The present study describes a novel mutation (R33L) in the GJA3 associated with finely granular embryonal cataract. These findings expand the mutation spectrum of GJA3 in association with congenital cataract.

A recurrent FBN1 mutation in an autosomal dominant ectopia lentis family of Indian origin.

PURPOSE: To identify the genetic defect in an autosomal dominant ectopia lentis (EL) family having 27 affected members in four generations. METHODS: Detailed family history and clinical data were recorded for 48 family members including 24 persons with isolated ectopia lentis. Candidate gene regions at 5q and 15q known to be linked with ectopia lentis were analyzed using fluorescent labeled microsatellite markers. Mutation screening in the candidate gene, fibrillin-1 (FBN1), at 15q was performed by bidirectional sequencing of the amplified products. RESULTS: A maximum LOD score of 5.74 at theta=0.0 was obtained with marker D15S1024 in close proximity to FBN1 at 15q21. Mutation screening in FBN1 identified a C>T transition at nucleotide position c.718. This nucleotide change resulted in the substitution of highly conserved arginine by cysteine at codon 240 (R240C). This nucleotide substitution was not seen in any unaffected member of the family. CONCLUSIONS: We report a recurrent R240C mutation in FBN1 in an autosomal dominant ectopia lentis family. This mutation has previously been reported in a family with isolated ectopia lentis, in another family with ectopia lentis and involvement of the skeleton and integument, and in one person with classic Marfan syndrome. This is the largest family with isolated ectopia lentis reported to date. The results of the present study provide convincing evidence for a correlation of R240C and isolated ectopia lentis. In addition, this is the first report of molecular characterization in an ectopia lentis family of Indian origin.

A novel mutation in GJA8 associated with autosomal dominant congenital cataract in a family of Indian origin.

PURPOSE: To identify the genetic defect in an autosomal dominant congenital cataract family, having 15 members in three generations, affected with bilateral cataract that gave the appearance of "full moon" with Y-sutural opacities. METHODS: A detailed family history and clinical data were recorded. A genome-wide scan by two point linkage analysis using nearly 400 microsatellite markers in combination with multipoint lod score and haplotype analysis was carried out. Mutation screening was performed in the candidate gene by bidirectional sequencing of amplified products. RESULTS: A maximum two point lod score of 5.45 at theta=0.00 was obtained with marker D1S534. Haplotype analysis placed the cataract locus to a 14.1 cM region between D1S221 and D1S498, in close proximity to the gene for the gap junction channel protein connexin 50 (GJA8) at 1q21. Mutation screening in GJA8 identified a novel G>C transversion at nucleotide position c.235. This nucleotide change resulted in the substitution of highly conserved valine by leucine at codon 79 (V79L). This nucleotide substitution was neither seen in any unaffected member of the family nor in 180 unrelated control subjects (360 chromosomes) from same ethnic background tested by sequence analysis of GJA8. CONCLUSIONS: The present study describes the mapping of a locus for congenital cataract that appeared like "full moon" with Y-sutural opacities at 1q21 and identifies a previously unreported mutation in GJA8. These findings thus expand the mutation spectrum of GJA8.

A novel fan-shaped cataract-microcornea syndrome caused by a mutation of CRYAA in an Indian family.

PURPOSE: The molecular characterization of an Indian family having 10 members in four generations affected with a unique fan-shaped cataract-microcornea syndrome. METHODS: Detailed family history and clinical data were recorded. A genome-wide screening by two-point linkage analysis using more than 400 microsatellite markers in combination with multipoint lod score and haplotype analysis was carried out. Mutation screening was performed in the candidate gene by bi-directional sequencing of amplified products. RESULTS: The cataract-microcornea locus in this family was mapped to a 23.5 cM region on chromosome 21q22.3. Direct sequencing of the candidate gene CRYAA revealed a heterozygous C>T transition resulting in the substitution of the highly conserved arginine at position 116 by cysteine (R116C). CONCLUSIONS: This study provides the report of mapping a locus for syndromal cataract (cataract-microcornea syndrome) on 21q22.3. The mutation observed in CRYAA in the present family highlights the phenotypic heterogeneity of the disorder in relation to the genotype, as an identical mutation has previously been reported in an American family with a different type of cataract. The "fan-shaped cataract" observed in the present family has not been reported before.

Sutural cataract associated with a mutation in the ferritin light chain gene (FTL) in a family of Indian origin.

PURPOSE: The molecular characterization of 27 members of an Indian family, with 13 members in four generations, affected with Y-sutural congenital cataract. METHODS: Detailed family history and clinical data were collected. A genome-wide scan by two-point linkage analysis using more than 400 microsatellite markers in combination with multipoint lod score and haplotype analysis was performed. Mutation screening was carried out in the candidate gene by bi-directional sequencing of amplified products. RESULTS: A maximum two-point lod score of 6.37 at theta=0.00 was obtained with marker D19S879. Haplotype analysis placed the cataract locus to a 5.0 cM region between D19S902 and D19S867, in close proximity to the L-ferritin light chain gene (FTL) on chromosome 19q13.3. Hematological tests in two affected individuals showed very high levels of serum ferritin without iron overload leading to the diagnosis of hyperferritinemia-cataract syndrome. Mutation screening in FTL identified a G>A change at position 32 (c.-168G>A) in a highly conserved 3 nucleotide motif that forms a loop structure in the iron responsive element (IRE) in the 5'-untranslated region (5'-UTR). This nucleotide alteration was neither seen in any unaffected member of the family nor found in 50 unrelated control subjects. CONCLUSIONS: The present study is the first report of a Y-sutural congenital cataract mapping to 19q13.3. The mutation observed in FTL in this family highlights the phenotypic heterogeneity of the disorder in relation to the genotype as the identical mutation (32 G>A) has previously been reported in two Italian families with entirely different phenotypes. It is also the first report of hereditary hyperferritinemia-cataract syndrome in a family of Indian origin.

Genome-wide association study of 25(OH) Vitamin D concentrations in Punjabi Sikhs: Results of the Asian Indian diabetic heart study.

Vitamin D deficiency is implicated in multiple disease conditions and accumulating evidence supports that the variation in serum vitamin D (25(OH)D) levels, including deficiency, is under strong genetic control. However, the underlying genetic mechanism associated with vitamin 25(OH)D concentrations is poorly understood. We earlier reported a very high prevalence of vitamin D deficiency associated with an increased risk for type 2 diabetes and obesity in a Punjabi Sikh diabetic cohort as part of the Asian Indian diabetic heart study (AIDHS). Here we have performed the first genome-wide association study (GWAS) of serum 25(OH)D on 3538 individuals from this Punjabi Sikh population. Our discovery GWAS comprised of 1387 subjects followed by validation of 24 putative SNPs (P<10(-4)) using an independent replication sample (n=2151) from the same population by direct genotyping. A novel locus at chromosome 20p11.21 represented by rs2207173 with minor allele frequency (MAF) 0.29, [ß=-0.13, p=4.47×10(-9)] between FOXA2 and SSTR4 was identified to be associated with 25(OH)D levels. Another suggestive association signal at rs11586313 (MAF 0.54) [ß=0.90; p=1.36×10(-6)] was found within the regulatory region of the IVL gene on chromosome 1q21.3. Additionally, our study replicated 3 of 5 known GWAS genes associated with 25(OH)D concentrations including GC (p=0.007) and CYP2R1 (p=0.019) reported in Europeans and the DAB1 (p=0.003), reported in Hispanics. Identification of novel association signals in biologically plausible regions with 25(OH)D metabolism will provide new molecular insights on genetic drivers of vitamin D status and its implications in health disparities.

Genome-wide association studies in the Japanese population identify seven novel loci for type 2 diabetes.

Genome-wide association studies (GWAS) have identified more than 80 susceptibility loci for type 2 diabetes (T2D), but most of its heritability still remains to be elucidated. In this study, we conducted a meta-analysis of GWAS for T2D in the Japanese population. Combined data from discovery and subsequent validation analyses (23,399 T2D cases and 31,722 controls) identify 7 new loci with genome-wide significance (P<5 × 10(-8)), rs1116357 near CCDC85A, rs147538848 in FAM60A, rs1575972 near DMRTA1, rs9309245 near ASB3, rs67156297 near ATP8B2, rs7107784 near MIR4686 and rs67839313 near INAFM2. Of these, the association of 4 loci with T2D is replicated in multi-ethnic populations other than Japanese (up to 65,936 T2Ds and 158,030 controls, P<0.007). These results indicate that expansion of single ethnic GWAS is still useful to identify novel susceptibility loci to complex traits not only for ethnicity-specific loci but also for common loci across different ethnicities.