['To search for MYOC mutations in Peruvian primary open angle glaucoma (POAG) families.', 'Two patients from each of the 11 POAG Peruvian families were screened for sequence variants in MYOC coding exons by conformational sensitive gel electrophoresis and sequencing was performed on the samples indicating probable sequence changes.', 'We detected 2 families bearing distortions of conformational sensitive gel electrophoresis indicating mutations. Sequencing of these samples revealed coding sequence changes. A native Andean descent family presented with a MYOC mutation, Asn480Lys (C-->G at nucleotide 1440). This is different from the previously reported C-->A change at nucleotide 1440 that causes Asn480Lys in 2 unrelated French and Dutch families with glaucoma of variable expressivity, and indicates a third independent event. A second family of admixed origin showed the presence of the known Arg76Lys polymorphism.'] Does recurrent Myocilin Asn480Lys glaucoma causative mutation arise de novo in a family of Andean descent?