Asunto(s)
Hidrocarburo de Aril Hidroxilasas/genética , Proteínas del Citoesqueleto/genética , Proteínas del Ojo/genética , Glaucoma de Ángulo Abierto/genética , Glaucoma de Ángulo Abierto/patología , Glicoproteínas/genética , Mutación/genética , Adulto , Edad de Inicio , Secuencia de Bases , Citocromo P-450 CYP1B1 , Análisis Mutacional de ADN , Femenino , Glaucoma de Ángulo Abierto/enzimología , Glaucoma de Ángulo Abierto/epidemiología , Humanos , India/epidemiología , Masculino , Datos de Secuencia MolecularRESUMEN
OBJECTIVE: To identify and evaluate MYOC variant alleles among patients with primary open-angle glaucoma (POAG) and age-matched control subjects in an Indian population. METHODS: Three hundred fifteen patients with POAG and 100 unrelated control subjects from the same ethnic background were enrolled in the study. The coding sequence of MYOC was amplified by polymerase chain reaction using genomic DNA, followed by sequencing of the polymerase chain reaction products. Four single nucleotide polymorphisms were genotyped in different Indian subpopulations comprising 1466 individuals using SEQUENOM's homogeneous MassEXTEND assay. RESULTS: One novel mutation (Gly399Asp), 6 reported mutations (Gln48His, Thr256Met, Thr353Ile, Gln368Stop, Pro370Leu, and Ala427Thr), and 6 single nucleotide polymorphisms were identified in MYOC. Ala427Thr was identified in a patient with POAG and Parkinson disease. Four single nucleotide polymorphisms genotyped in control subjects were highly heterozygous and displayed a similar pattern of linkage disequilibrium among all linguistic groups. CONCLUSIONS: MYOC mutations account for 2.2% of POAG cases. The Gln368Stop mutation (common among persons of the white race) found in 2 families does not seem to be of white race origin. Identification of a MYOC mutation (Ala427Thr) in a patient with POAG and Parkinson disease is interesting with respect to reported interaction of myocilin with synucleins. CLINICAL RELEVANCE: Studying the genetics of POAG is helpful for preclinical identification and for better disease management.
Asunto(s)
Proteínas del Citoesqueleto/genética , Proteínas del Ojo/genética , Glaucoma de Ángulo Abierto/genética , Glicoproteínas/genética , Mutación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Análisis Mutacional de ADN , Femenino , Genotipo , Glaucoma de Ángulo Abierto/etnología , Humanos , India/epidemiología , Masculino , Persona de Mediana Edad , Linaje , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
BACKGROUND: We investigated the molecular basis of primary open-angle glaucoma (POAG) using Opticin (OPTC) as a candidate gene on the basis of its expression in the trabecular meshwork cells involved in the disease pathogenesis. Two hundred POAG patients and 100 controls were enrolled in this study. The coding sequence of OPTC was amplified by PCR from genomic DNA of POAG patients, followed by SSCP, DHPLC and DNA sequencing. Subsequent bioinformatic analysis, site-directed mutagenesis, quantitative RT-PCR and western blot experiments were performed to address the functional significance of a 'silent' change in the OPTC coding region while screening for mutations in POAG patients. RESULTS: We detected two missense (p.Glu66Gly & p.Ile89Thr) and one silent change (p.Phe162Phe; c.602 C>T) that was present in 3 different patients but in none of the 100 controls screened. The mutant (c.602T) mRNA was predicted to have remarkably different secondary structure compared to the wild-type transcript by in silico approaches. Subsequent wet-lab experiments showed lower expression of the gene both at the mRNA and protein levels. CONCLUSION: Our study suggests OPTC as a candidate gene for POAG. Further, it highlights the importance of investigating the 'silent' variations for functional implication that might not be apparent from only in silico analysis.
Asunto(s)
Proteínas de la Matriz Extracelular/biosíntesis , Proteínas de la Matriz Extracelular/genética , Glaucoma/genética , Proteoglicanos/biosíntesis , Proteoglicanos/genética , Adulto , Anciano , Secuencia de Aminoácidos , Secuencia de Bases , Estudios de Casos y Controles , Humanos , India , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Mutación Missense , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido NucleicoRESUMEN
PURPOSE: To evaluate the role of the optineurin gene (OPTN) in Indian primary open angle glaucoma (POAG) patients from different parts of the country. METHODS: Two hundred patients with POAG and 200 ethnically matched normal controls were recruited from various parts of India for the study. The entire coding region of OPTN along with the intron-exon boundaries were screened by PCR and single strand conformation polymorphism (SSCP) followed by direct sequencing. A rapid screening method was developed for some of the observed variants by denaturing high performance liquid chromatography (dHPLC). Four variants were also confirmed by digesting the amplicon with appropriate restriction enzymes. RESULTS: Seven nucleotide changes were observed in OPTN of which one was a putative mutation in exon 16 (Arg545Gln) that was observed in six POAG patients and not in the controls (p<0.05). The remaining variants comprised four single nucleotide polymorphisms (SNPs) in the coding region (Thr34Thr, Met98Lys, Arg149Arg, and Asn303Lys) and two in intron 6 (879-10G>A and 879-5C>T). But frequencies of the minor allele were not significantly different among the patients and controls. The Met98Lys variant that was identified to be a potential risk factor for NTG and POAG in some Asian populations and also for modulating IOP in Caucasian populations, did not exhibit any significant association to the disease phenotype. CONCLUSIONS: Despite a putative mutation (Arg545Gln) in some patients, the present study does not suggest a significant involvement of OPTN in POAG patients of Indian origin.