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.

Genetics of diabetes.

Diabetes mellitus is a complicated disease characterized by a complex interplay of genetic, epigenetic, and environmental variables. It is one of the world's fastest-growing diseases, with 783 million adults expected to be affected by 2045. Devastating macrovascular consequences (cerebrovascular disease, cardiovascular disease, and peripheral vascular disease) and microvascular complications (like retinopathy, nephropathy, and neuropathy) increase mortality, blindness, kidney failure, and overall quality of life in individuals with diabetes. Clinical risk factors and glycemic management alone cannot predict the development of vascular problems; multiple genetic investigations have revealed a clear hereditary component to both diabetes and its related complications. In the twenty-first century, technological advancements (genome-wide association studies, next-generation sequencing, and exome-sequencing) have led to the identification of genetic variants associated with diabetes, however, these variants can only explain a small proportion of the total heritability of the condition. In this review, we address some of the likely explanations for this "missing heritability", for diabetes such as the significance of uncommon variants, gene-environment interactions, and epigenetics. Current discoveries clinical value, management of diabetes, and future research directions are also discussed.

A nonsense mutation in C8orf37 linked with retinitis pigmentosa, early macular degeneration, cataract, and myopia in an arRP family from North India.

OBJECTIVE: This study aimed at identifying the underlying genetic defect in a consanguineous autosomal recessive retinitis pigmentosa (arRP) (RP-1175) family having RP with early macular degeneration, cataract, and myopia. METHODS: Whole-exome sequencing (WES) was performed on the DNA of the proband, and variants observed were validated in the rest of the affected and unaffected family members by Sanger sequencing. Different bioinformatics tools were applied to access the pathogenicity of the observed variant. RESULTS: A nonsense mutation i.e., c.555G > A (p.Trp185Ter) in C8orf37 in homozygous form, has been identified that segregated with the disease in the affected members. c.555G > A was absent in unaffected family members and in 107 ethnically matched controls, therefore ruling out its possibility of being a polymorphism. CONCLUSIONS: Present study identifies a nonsense mutation (c.555G > A) at codon 185 in C8orf37 linked with arRP, early macular degeneration, posterior subcapsular cataract, and myopia. The identical mutation has previously been reported in a Pakistani family with isolated RP and in a Chinese family with RP and macular degeneration. This variable expressivity of the identified mutation c.555G > A in C8orf37 in the analyzed Indian family may be attributed to the presence of the modifier alleles. Also, Trp185 might be a mutation hotspot in Asian arRP patients and in the future, p.Trp185Ter in C8orf37 may be tested during initial screening in arRP cases especially belonging to a similar population.

Recycling of All-Solid-State Li-ion Batteries: A Case Study of the Separation of Individual Components Within a System Composed of LTO, LLZTO and NMC.

With the current global projection of over 130 million electric vehicles (EVs), there soon will be a need for battery waste management. Especially for all-solid-state lithium-ion batteries (lithium ASSBs), aspects of waste management and circular economy have not been addressed so far. Within such ASSBs, the use of solid-electrolytes like garnet-type Li6.5 La3 Zr1.5 Ta0.5 O12 (LLZTO) may shift focus on strategies to recover not only the transition metal elements but also elements like La/Zr/Ta. In this work, we present a two-step recycling approach using citric acid as the leaching agent to separate and recover the individual components of a model cell comprising of Li4 Ti5 O12 (LTO) anode, Li6.5 La3 Zr1.5 Ta0.5 O12 (LLZTO) garnet electrolyte and LiNi1/3 Mn1/3 Co1/3 O2 (NMC) cathode. We observe that by adjusting the concentration of citric acid, it was possible to separate the materials from each other without strong mixing of individual phases and also to maintain their principle performance characteristics. Thus, the process developed has a potential for upscaling and can guide towards considering separation capability of battery components in the development of lithium ASSBs.

A naphthalimide-tyrosine-based dicationic amphiphile for intracellular 'turn-on' simultaneous detection of ATP and CTP.

We have developed a new naphthalimide-based amphiphile (YN-1) for the simultaneous detection of ATP and CTP. In YN-1, the cationic tyrosine-linked polyamine (+2 charge, hydrophilic unit) is appended at the -peri position of naphthalimide (hydrophobic unit). YN-1 and its Boc-protected compound 4 were characterized using state-of-the-art spectroscopic and optical techniques such as NMR, IR, UV-vis and fluorescence. The fluorescence data revealed that YN-1 showed a 'turn-on' (λem = 440 nm) fluorescence response for nanomolar detection of nucleoside triphosphates such as ATP and CTP in 20% HEPES buffer-DMSO solution. YN-1 also showed a concentration-based discrimination between ATP and CTP. YN-1 has been successfully applied for bioimaging of nucleoside triphosphates in MCF-7 live cancer cells with good compatibility. Therefore, the important findings from the present work will provide insight for future development of fluorescent probes to detect various kinds of essential nucleoside triphosphates.

Molecular diagnosis of autosomal dominant congenital cataract in two families from North India reveals a novel and a known variant in GJA8 and GJA3.

Aims: The study aims to detect the underlying genetic defect in two autosomal dominant congenital cataract (ADCC) families. Methods: A detailed family history was collected, pedigrees were drawn, and slit-lamp examination and lens photography were performed. Mutation screening was carried out in the genes for crystallins and connexins by PCR and Sanger sequencing. Ethnically matched controls were tested for the identified variants. Different bioinformatics tools were used to assess the pathogenicity of the observed variants. Results: In an ADCC family with total cataract, a novel change (c.166A > G) (p.Thr56Ala) in GJA8 was identified. In another ADCC family with nuclear cataract, c.134G > C (p.Trp45Ser) in GJA3 has been detected. These variants co-segregated completely in patients in their respective families and were neither observed in unaffected family members nor in ethnically matched 100 controls, excluding them as polymorphisms. Conclusions: The present study identifies a novel variant c.166A > G (p.Thr56Ala) in GJA8 in an ADCC family having total cataract and a previously known mutation c.134G > C (p.Trp45Ser) in GJA3 in another ADCC family. Thr56 in GJA8 seems to be a mutation hotspot, as previously an ADCC Mauritanian family harbored a different substitution (p.Thr56Pro) at the same codon, although for a different phenotype (nuclear cataract). Similarly, Trp45 in GJA3 appears as a mutation hotspot, as p.Trp45Ser has previously been reported for nuclear cataract in a Chinese ADCC family. p.Thr56 (GJA8) and p.Trp45 (GJA3) are in the extracellular loop 1 (EL1) in their respective connexin proteins, which, along with EL2, are essential for gap junction formation, hemichannel docking, and regulating the voltage gating of the channels. Hence, residues in these regions seem crucial for maintaining eye lens transparency.

On the Surface Modification of LLZTO with LiF via a Gas-Phase Approach and the Characterization of the Interfaces of LiF with LLZTO as Well as PEO+LiTFSI.

In this study we present gas-phase fluorination as a method to create a thin LiF layer on Li6.5La3Zr1.5Ta0.5O12 (LLZTO). We compared these fluorinated films with LiF films produced by RF-magnetron sputtering, where we investigated the interface between the LLZTO and the deposited LiF showing no formation of a reaction layer. Furthermore, we investigated the ability of this LiF layer as a protection layer against Li2CO3 formation in ambient air. By this, we show that Li2CO3 formation is absent at the LLZTO surface after 24 h in ambient air, supporting the protective character of the formed LiF films, and hence potentially enhancing the handling of LLZTO in air for battery production. With respect to the use within hybrid electrolytes consisting of LLZTO and a mixture of polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), we also investigated the interface between the formed LiF films and a mixture of PEO+LiTFSI by X-ray photoelectron spectroscopy (XPS), showing decomposition of the LiTFSI at the interface.

A missense mutation in TTC8/BBS8 affecting mRNA splicing in patients with non-syndromic retinitis pigmentosa.

Splicing disruption is one type of mutation mechanism for disease-predisposing alleles. To date, less than 30 mutations in TTC8/BBS8 have been reported; however, mutations affecting the splice site are rare. Generally missense mutations are assumed to alter protein function; however, reports have shown that mutations in protein coding exons can disrupt splicing by altering exonic splicing silencer or enhancer motifs. Hence, a missense mutation c.1347G > C (p.Q449H) involving final base of the exon 13 in the TTC8, previously identified by us to be linked with non-syndromic autosomal recessive retinitis pigmentosa (arRP), in an Indian family, that might deleteriously affect splicing has been functionally characterized. RNA was isolated, cDNA prepared and amplified using region-specific primers. PCR products were purified and sequenced bi-directionally by Sanger sequencing. Effect of mutation (c.1347G > C) on mRNA splicing has been predicted using bioinformatics tools. We reported that missense mutation (c.1347G > C) at the last base of exon 13 of TTC8 disrupted the canonical donor splice-site resulting in aberrant RNA splicing. A cryptic donor splice-site got activated 77 bases downstream of the authentic splice donor site in intron 13, resulting in the retention of 77 bases of intron 13, and a frameshift leading to pre-mature termination codon in exon 14 at codon 486. Further, duplication of exon 15 and fusion of its duplicated copy occurred with exon 13. The binding site for SC35 protein, normally involved in splicing, also got disrupted (as predicted by SpliceAid2 software), hence, leading to alternative splicing. Our findings strongly suggest that a missense mutation c.1347G > C in TTC8 disrupted the splice donor site causing retention of 77 bases of intron 13, resulting in a frameshift and subsequently introduced a pre-mature termination codon into exon 14, hence creating an altered mRNA transcript. These findings emphasize the significance of examining missense mutations especially in TTC8, to determine their pathogenic role through alternative splicing. Present findings also reiterate the notion that mutations in the TTC8/BBS8 cause phenotypic heterogeneity and does not always follow Mendelian genetics in this ciliopathy.

Clinical and molecular aspects of congenital aniridia - A review of current concepts.

Congenital aniridia is a pan ocular disorder characterized by partial or total loss of iris tissue as the defining feature. Classic aniridia, however, has a spectrum of ocular findings, including foveal hypoplasia, optic nerve hypoplasia, nystagmus, late-onset cataract, glaucoma, and keratopathy. The latter three are reasons for further visual compromise in such patients. This entity is often due to mutations in the PAX6 (Paired box protein Pax-6) gene. Recently, aniridia-like phenotypes have been reported due to non-PAX6 mutations as in PITX2, FOXC1, FOXD3, TRIM44, and CYP1B1 as well wherein there is an overlap of aniridia, such as iris defects with congenital glaucoma or anterior segment dysgenesis. In this review, we describe the various clinical features of classic aniridia, the comorbidities and their management, the mutation spectrum of the genes involved, genotype-phenotype correlation of PAX6 and non-PAX6 mutations, and the genetic testing plan. The various systemic associations and their implications in screening and genetic testing have been discussed. Finally, the future course of aniridia treatment in the form of drugs (such as ataluren) and targeted gene therapy has been discussed.

Compositional Dependence of Li-Ion Conductivity in Garnet-Rich Composite Electrolytes for All-Solid-State Lithium-Ion Batteries-Toward Understanding the Drawbacks of Ceramic-Rich Composites.

Composite electrolytes comprising a polymer plus Li salt matrix and embedded fillers have the potential of realizing high lithium-ion conductivity, good mechanical properties, wide electrochemical operational window, and stability against metallic lithium, all of which are essential for the development of high-energy-density all-solid-state lithium-ion batteries. In this study, a solvent-free approach has been used to prepare composite electrolytes with tetragonal and cubic phase garnets synthesized via nebulized spray pyrolysis with polyethylene oxide (PEO) being the polymer component. Electrochemical impedance spectroscopy (EIS) is used to examine a series of composites with different garnets and weight fractions. The results show that with the increase in the ceramic weight fraction in the composites, ionic conductivity is reduced and alternative Li-ion transport pathways become accessible for composites as compared to the filler-free electrolytes. An attempt is made to understand the ion transport mechanism within the composites. The role of the chemical and morphological properties of the ceramic filler in polymer-rich and ceramic-rich composite electrolytes is explained by studying the blends of nonconducting ceramics with the Li-conducting polymer, indicating that the intrinsic conductivity of the ceramic filler significantly contributes to the overall conductive process in the ceramic-rich systems. Further, the stability of the garnet/PEO interface is studied via X-ray photoelectron spectroscopy, and its impact on the lithium-ion transport is studied using EIS.

Association of Erythropoietin Gene Polymorphisms With Type 2 Diabetic Retinopathy in Adult Patients From Northern India.

OBJECTIVES: Our aim in this study was to determine the association of erythropoietin (EPO) gene polymorphisms with diabetic retinopathy in patients with type 2 diabetes from northern India. METHODS: In this case-control study, we recruited 614 participants, consisting of 302 diabetic retinopathy cases and 312 individuals with confirmed type 2 diabetes without retinopathy as controls. EPO polymorphism analysis was performed in all participants using polymerase chain reaction and direct DNA sequence analysis. RESULTS: The genotype distribution and allele frequency of the c.246+265G>A (rs507392) polymorphism differed significantly (p<0.05) between the retinopathy and control groups. For the -1306C>A (rs1617640) polymorphism, genotype distribution among the 2 groups analyzed differed significantly (p=0.047), but the distribution of allele frequency was not found to be statistically significant (p=0.07). For the c.∗772G>T (rs551238) variant, genotype distribution did not differ significantly when comparing the 2 groups (p=0.062), but allele frequency distribution did differ significantly (p=0.045). For the polymorphisms analyzed, namely rs507392 and rs1617640, a statistically significant association with retinopathy was observed (dominant model: adjusted odds ratio [OR], 2.23; 95% confidence interval [CI], 1.36 to 3.35; p<0.01; codominant model: adjusted OR, 1.45; 95% CI, 1.00 to 2.09; p=0.048). However, no significant association between c.∗772G>T (rs551238) polymorphism and diabetic retinopathy was found. CONCLUSIONS: Our findings show 2 polymorphisms (c.246+265G>A [rs507392] and -1306C>A [rs1617640]) in EPO to be risk factors for type 2 diabetic retinopathy in a northern Indian cohort. To our knowledge, this is the first report from India to demonstrate an association between EPO gene polymorphisms and retinopathy.

Pre-clinical and cellular toxicity evaluation of 7-methylxanthine: an investigational drug for the treatment of myopia.

The present study entails the toxicity evaluation of 7-methyl xanthine (7-MX), first of its kind molecule found effective in phase II clinical trials for the treatment of myopia, in comparison to other clinically used xanthines i.e., caffeine and theobromine. For acute toxicity evaluation, 7-MX was administered orally in two rodent species (rat and mice) at the doses of 300 mg/kg and 2000 mg/kg and for repeated dose 28-d oral toxicity, at 250, 500, and 1000 mg/kg in rats. Further, cellular toxicity was evaluated in normal breast epithelial (fR2), rat brain C6 glioma (C6 glioma) and human colorectal (Caco-2) cell lines. Also, the cell uptake assay to determine the intestinal permeability of drug was performed in Caco-2 cells. In acute toxicity, 7-MX treatment showed no mortality and toxicity, whereas 66.6% (mice) and 33.3% (rat) mortality was observed in both caffeine and theobromine treatment groups. In repeated dose 28-d oral toxicity, 7-MX treatment was found to have no-observed-adverse-effect level up to the dose of 1000 mg/kg in the present study conducted as per OECD guidelines 407. Also, very high IC50 value of 305.5 and 721 µg/mL was observed for 7-MX in fR2 and C6 glioma cells, respectively. In Caco-2 cells, linear bioavailability and high % cell viability was observed. Thus, 7-MX may be classified as Globally Harmonized System (GHS) category 5 drug with LD50 >2000-5000 mg/kg. Also, the repeated dose 28-d oral toxicity study demonstrated 7-MX to be nontoxic in nature, with cell line toxicity results further endorsing its nontoxic nature.

Novel mutation in MKKS/BBS6 linked with arRP and polydactyly in a family of North Indian origin.

BACKGROUND: To identify the underlying genetic defect in a fourth-generation autosomal recessive retinitis pigmentosa (arRP) family. Detailed family history and clinical data were collected from nine members, including three affected, from an arRP family. METHODS: Whole-exome sequencing (WES) was performed on DNA sample of an affected individual IV: 2. Variants obtained by WES were annotated using Ion Reporter Software (ver. 5.2). Potential pathogenic variants detected in an affected member were validated in other affected and unaffected family members by Sanger sequencing. Further 150 ethnically-matched controls were tested for the variant that co-segregated completely with disease in the family, so as to exclude it as a polymorphism. Various web-based bioinformatics tools were also applied to access pathogenic potential of the observed variant. RESULTS: All the three patients had RP with polydactyly of both hands and feet, however, they did not show other symptoms of Bardet-Biedl syndrome (BBS) or McKusick-Kaufmann Syndrome (MKKS). A novel missense mutation, that is, c.518A>C (p.His173Pro) was identified in MKKS/BBS6 that co-segregated completely with the disease phenotype in all the three affected members and was not observed in six unaffected members of the family. Also the c.518A>C change was not observed in 150 ethnically matched controls (300 chromosomes), hence excluding it as a polymorphism. CONCLUSIONS: Present study is the second report of identifying a novel mutation in MKKS/BBS6 that is linked with arRP in association with polydactyly, however, with no other signs of BBS or MKKS. These findings further expand the mutation spectrum of MKKS/BBS6 for arRP with polydactyly.

Association of TNF-α gene alterations (c.-238G>A, c.-308G>A, c.-857C>T, c.-863C>A) with primary glaucoma in north Indian cohort.

BACKGROUND: Tumor Necrosis Factor-alpha (TNF-α) a pleuripotent pro-inflammatory cytokine, is involved in retinal ganglion cells apoptosis in glaucoma. Thus present study aimed to analyze the association of TNF-α promoter region alterations (c.-238G>A (rs361525), c.-308G>A (rs1800629), c.-857C>T (rs1799724) and c.-863C>A (rs1800630)) with glaucoma in north Indian cohort. METHODS: Present hospital based case control study involved 286 glaucoma patients (Primary Open Angle Glaucoma [POAG], Primary Angle Closure Glaucoma [PACG], Primary Congenital Glaucoma [PCG]) and 300 controls. TNF-α gene alteration (c.-238G>A (also referred as c.-418G>A; NM_000594.3)), c.-308G>A (c.-488G>A; NM_000594.3), c.-857C>T (c.-1037C>T; NM_000594.3) and c.-863C>A (c.-1043C>A; NM_000594.3) harboring regions were PCR amplified and sequenced by Sanger sequencing. Allele frequency and genotype distribution in glaucoma cases and controls were compared using chi-square test and genetic association tested using different genetic models. RESULTS: Statistically significant genotype and allelic association was observed between glaucoma cases and controls for c.-308G>A and c.-863C>A alterations (p = 0.001, p = 0.001; p = 0.001, p = 0.001 respectively). AA genotype of c.-308G>A conferred ~7 fold increased risk towards glaucoma (OR = 6.82, 95% CI = 2.82-16.53, p = 0.001). c.-863C>A alteration under dominant, recessive and co-dominant genetic models conferred ~2 fold increased risk for glaucoma. However, no association for c.-238G>A and c.-857C>T variants with glaucoma was observed. Further, three haplotypes (GGCA, GACC and GACA) (OR = 0.48, 95% CI = 0.35-0.67, p = 0.001; OR = 0.58, 95% CI = 0.36-0.91, p = 0.019 and OR = 0.16, 95% CI = 0.05-0.51, p = 0.002, respectively) conferred protective role towards glaucoma. CONCLUSIONS: Present study is the first to indicate significant association of c.-308G>A and c.-863C>A alterations with glaucoma in cases from north Indian cohort. Also it is the first study from India to analyze the association and interaction of four promoter region alterations (c.-238G>A, c.-308G>A, c.-857C>T and c.-863C>A) in TNF-α resulting in three protective haplotypes.

A novel mutation in MERTK for rod-cone dystrophy in a North Indian family.

OBJECTIVE: To identify the underlying genetic defect of childhood-onset severe rod-cone dystrophy (RCD) in a consanguineous family from North India with autosomal recessive retinitis pigmentosa. METHODS: A detailed family history, clinical data, and blood samples were collected from 11 members of the family, including 4 affected by an autosomal recessive rod-cone dystrophy (arRCD), and DNA was extracted. Whole-exome sequencing (WES) was performed on DNA samples of proband and her unaffected maternal uncle. Ion Reporter software (ver. 4.4) was used for the annotation of variants obtained by WES. The variants detected in proband were tested for validation in all other affected and unaffected family members using Sanger sequencing technique. RESULTS: We have identified a novel nonsense mutation-c.1647T>G (p.Tyr549Ter)-in the exon 11 of MERTK that co-segregated completely with the disease phenotype in all the 4 affected members and was not observed in the 7 unaffected members of the family. This mutation was also not detected in 120 ethnically matched controls (240 chromosomes), hence excluding it as a polymorphism. CONCLUSIONS: MERTK has a role in retinal pigment epithelium as a regulator of rod outer segments' phagocytosis. Due to c.1647T > G substitution, the stop codon (p.Tyr549Ter) appears early in the transcript. It seems that either the altered transcript would degenerate through nonsense-mediated decay (NMD) or potentially form truncated protein lacking a functionally important domain (i.e., tyrosine kinase domain). These findings thus further expand the mutation spectrum in MERTK and substantiate its role in the pathogenesis of retinal dystrophy.

A novel mutation in the PRPF31 in a North Indian adRP family with incomplete penetrance.

PURPOSE: To identify the underlying genetic defect for non-syndromic autosomal dominant retinitis pigmentosa (adRP) with incomplete penetrance in a North Indian family. METHODS: Family history and clinical data were collected. Linkage analysis using 72 fluorescently labeled microsatellite markers flanking all the 26 candidate genes known for adRP was performed. Mutation screening in candidate gene at the mapped region was performed by bi-directional DNA sequencing. RESULTS: Positive two-point lod scores > 1.0 (θ = 0.000) suggestive of linkage were obtained with markers D19S572, D19S927 and D19S926 at 19q13.42, in the vicinity of PRPF31 gene. Mutation screening in all the 14 exonic regions and intron-exon boundaries of PRPF31 revealed a novel change, i.e. c.896G>A (p.Cys299Tyr) in exon eight. The observed change segregated in heterozygous form in all the six affected members and in three carriers, consistent with incomplete penetrance. This substitution was not observed in tested 15 unaffected members and in 200 ethnically matched controls. CONCLUSION: Present study describes mapping of a locus for non-syndromic adRP with incomplete penetrance at 19q13.42 in a North Indian family and identifies a novel missense mutation (p.Cys299Tyr) in PRPF31 localized at the mapped interval. The observed substitution lies in the NOP domain of PRPF31 that exhibit RNA and protein binding surfaces and thus may interfere in the formation of spliceosome complex. Due to p.Cys299Tyr substitution hydrogen bonds are generated, which may result in conformational changes and PRPF31 protein deformity. Present findings further substantiate the role of PRPF31 in adRP with incomplete penetrance and expand the mutation spectrum of PRPF31.

Screening of CYP1B1 Arg368His as predominant mutation in North Indian primary open angle glaucoma and juvenile onset glaucoma patients.

In India, mutations in Cytochrome P450 (CYP1B1) are a predominant cause of not only primary congenital glaucoma (PCG) but also involved in primary open angle glaucoma (POAG) and juvenile onset glaucoma (JOAG). After ethical clearance, 100 POAG patients, 30 primary angle closure glaucoma (PACG) patients and 130 ethnically matched controls were recruited in this study. Genomic DNA was isolated from the blood and screened for p.Arg368His mutation in CYP1B1 by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). On PCR-RFLP, 10/100 cases (10%) were found positive for Arg368His mutation. In North Indian POAG cases studied, p.Arg368His mutation was found only in heterozygous state. The frequency of p.Arg368His CYP1B1 mutation in heterozygote state (10.0%) observed in our study in North Indian POAG patients is the highest in comparison to frequency observed in other ethnic groups from Southern and Eastern India.

Association analysis of PPARγ (p.Pro12Ala) polymorphism with type 2 diabetic retinopathy in patients from north India.

BACKGROUND: The present study aimed to examine the association of PPARγ (p.Pro12Ala) polymorphism with type 2 diabetic retinopathy (DR) in patients from north India. MATERIAL AND METHODS: In this case-control association study a total of 1325 subjects (717 DR patients and 608 individuals with confirmed type 2 diabetes mellitus (T2DM) without retinopathy taken as controls (CDR)), were recruited. Genotyping for PPARγ (p.Pro12Ala) polymorphism was performed by Taqman SNP Genotyping Assays using Real time PCR. RESULTS: Statistically significant differences were observed between the two analyzed groups in the duration of diabetes and random blood glucose levels (p = 0.000 and p = 0.011, respectively). However, genotype and allele frequency distribution of PPARγ (p.Pro12Ala) polymorphism did not differ significantly between DR and CDR groups (p = 0.507 and 0.625, respectively). CONCLUSIONS: These findings suggest no significant association of p.Pro12Ala polymorphism with retinopathy in tested type 2 diabetic retinopathy patients as compared to T2DM individuals take as controls. To our knowledge, this is the first report of association analysis of p.Pro12Ala polymorphism in PPARγ in DR patients from India.