Identification of a new mutation in the TIGR/MYOC gene causing juvenile glaucoma

Abstract

Abstract: : Purpose: To screen for mutations in genes causing juvenile glaucoma in an extensive Hispanic (Venezuelan) family. Methods: Direct sequencing of genomic DNA, obtained from peripheral blood leukocytes, was used to detect exonic mutations. A complete ophthalmic examination was performed including best–corrected visual acuity, visual field testing, slit–lamp examination with gonioscopy, indirect ophthalmoscopy, and fundus photography. Results: A novel heterozygous mutation pG399N of the MYOC gene was detected in the probands. This novel MYOC sequence variation resulted in substitution of a highly conserved glycine residue for an asparagine within the olfactomedin domain. Clinical examination of the probands and relatives showed juvenile glaucoma with age of onset ranging from 22 to 33 years, high intraocular pressures and blindness in several family members. Conclusions: G399N mutation in exon 3 of the TIGR/MYOC gene causes juvenile glaucoma in a large family of Venezuelan extraction. The phenotype is characterized by early age of onset and diagnosis, and highly elevated and difficult to control IOP with progression to blindness.

Keywords: genetics • gene screening • anterior segment