Two novel myocilin mutations in a Chinese family with primary open-angle glaucoma

PURPOSE To investigate the genetic linkage of primary open-angle glaucoma (POAG) in a Chinese family. METHODS We have screened for myocilin (MYOC) gene mutations in a glaucoma family of five generations. There are fifty-six members of whom 11 were confirmed to have POAG , two with ocular hypertension were considered as POAG suspect, and the remaining 43 were asymptomatic. We also recruited 200 unrelated healthy Chinese subjects as normal control. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and DNA sequencing were used to identify mutations in the three exons of MYOC. Presymptomatic diagnoses were made for the family members seeking consultation based on the results of both clinical examination and genetic analysis. RESULTS Among three allelic variants identified in this pedigree (Pro13Leu [38 C-->T], Arg76Lys [227G-->A], and Gln337Stop [1009C del]), Pro13Leu and Gln337Stop were reported to be novel mutations while Arg76Lys has been previously documented. Our results show that all 11 POAG patients carry the Gln337Stop mutation and that four POAG patients and one POAG suspect (V:2) were found to have the Pro13Leu mutation. In addition, Arg76Lys polymorphism was identified in two patients and a POAG suspect (V:5). CONCLUSIONS Pro13Leu and Gln337Stop mutations of MYOC are likely responsible for the etiology of POAG in this pedigree, but the causative mechanism needs further research.