Prevalence of CYP1b1 and Myocilin Mutations Among Juvenile Onset Primary Open Angle Glaucoma Patients of Indian Origin

Abstract

Purpose: : To evaluate the prevalence of myocilin and CYP1B1 mutations among juvenile onset primary open angle glaucoma (JOAG) patients.

Methods: : Blood samples of 30 unrelated JOAG patients of East Indian ethnicity were analyzed after an informed consent. JOAG patients were diagnosed as those presenting with open angle glaucoma between 10-40years of age with IOP >22mmHg and glaucomatous optic atrophy in both eyes after excluding all secondary causes of glaucoma. The coding sequences of CYP1b1 and Myocilin were amplified from the genomic DNA followed by direct sequencing (forward and reverse) among the JOAG patients and 60 ethnically matched controls.

Results: : The mean age of patients was 23.4 ±4.7 yrs. The most common variation in the Myocilin gene was seen at exon 1 c.G278T(S93I).This was present among 24 patients and 30 controls. No polymorphisms were found in either exon 2 or 3 of myocilin in either the patients or the controls. Two single nucleotide polymorphisms (SNP) were noted on exon 2 of CYP1B1: c.142 C>G (R48G) and c 355G>T(A119S).These were present in 18 patients and in only 5 controls. Three most common SNP’s on exon 3 of CYP1B1 were: c1294G>C (v432L), c.1347 T>C (D449D) and c.1358 A>G (N453S).These were present in 20 cases and 12 controls.

Conclusions: : CYP1B1 variations among JOAG patients of Indian ethnicity are more common than the variations seen in the Myocilin gene. The former are more likely to be associated with the causation of juvenile onset primary open angle glaucoma in this population.

Keywords: genetics • anterior segment • clinical (human) or epidemiologic studies: prevalence/incidence