The mutational spectrum of Myocilin gene among familial versus sporadic cases of Juvenile onset open angle glaucoma.

PURPOSE: Juvenile onset primary open angle glaucoma (JOAG) is a rare disorder associated with high IOP and progressive optic neuropathy in patients diagnosed before the age of 40 years. While in some populations it has primarily an autosomal dominant pattern of inheritance, in others it occurs in a primarily sporadic form. The main aim of the study was to assess the relative prevalence of Myocilin (MYOC) mutations in familial versus sporadic cases of JOAG. METHODS: We screened 92 unrelated (sporadic) JOAG patients, and 22 affected families (70 affected members and 36 unaffected) for variations in the MYOC gene. We also analyzed the clinical features associated with these variations. RESULTS: Three coding sequence variants were identified as mutations causing JOAG. Four families segregated distinct mutations at Gly367Arg, and two families at Gln337Arg, while only two sporadic JOAG cases harbored MYOC mutations (Gly367Arg and Gln48His). The frequency of MYOC mutations in familial cases (27%) was significantly higher than in sporadic JOAG cases (2%); p = 0.001. A 90% penetrance for the Gly367Arg variant was seen by the age of 40 years in our patients. Characteristic allele signatures, indicative of specific founder effects, were not observed for the Gly367Arg mutation that was looked for in 12 patients among 2 geographically close families, which harbored this mutation. CONCLUSION: Our data demonstrated that genetic screening for MYOC mutations should be focused toward cases with familial rather than sporadically occurring JOAG.

Long-term functional outcomes of different subtypes of primary congenital glaucoma.

AIM: To analyse long-term visual outcomes across different subtypes of primary congenital glaucoma (PCG). METHODS: Patients with PCG with a minimum of 5-year follow-up post surgery were included in the study. Snellen visual acuity recordings taken at their last follow-up were analysed. We evaluated the results using Kaplan-Meier curves to predict the probability of maintaining good vision (as defined by a visual acuity of 6/18 or better) in our patients after 30-year follow-up. The results were also analysed to determine whether there were any differences in the long-term visual acuities with time between the neonatal and infantile PCG. We also analysed the reasons for poor visual outcomes. RESULTS: We assessed a cohort of 140 patients with PCG (235 eyes) with an average follow-up of 127±62.8 months (range 60-400 months). Overall, the proportion of eyes with good visual acuity was 89 (37.9%), those with fair visual acuity between 6/60 and 6/18 was 41 (17.4%), and those with poor visual acuity (≤6/60) was 105 (44.7%). We found a significant difference (p=0.047) between neonatal and infantile patients with PCG whereby the neonatal cohort fared worse off in terms of visual morbidity. On Kaplan-Meier analysis, the cumulative probability of survival of a visual acuity of 6/18 or better was more among the infantile PCG in comparison to the neonatal PCG (p=0.039) eyes, and more among the bilateral than the unilateral affected eyes (p=0.029). Amblyopia was the most important cause for poor visual acuity as shown on a Cox proportional-hazards regression model. CONCLUSIONS: Long-term visual outcomes of infantile are better than neonatal PCG. Eyes with unilateral have worse visual outcomes compared with those with bilateral PCG because of the development of dense amblyopia.