CLINICAL-FEATURES OF 5 PEDIGREES GENETICALLY LINKED TO THE JUVENILE GLAUCOMA LOCUS ON CHROMOSOME 1Q21-Q31

Primary juvenile glaucoma is a rare form of glaucoma that typically af fects individuals between 3 and 20 years of ages and is inherited as a n autosomal dominant trait. One gene responsible for this condition ha s been localized to the 1q21-q31 region of chromosome 1. To investigat e the clinical features of this form of glaucoma, the authors have exa mined the affected members of five pedigrees demonstrating genetic lin kage to the 1q21-q31 locus. Methods: Clinical characterization of 23 a ffected patients was performed. Genetic linkage to the 1q21-q31 locus was confirmed by segregation of the disease trait in each pedigree wit h genetic markers located in the 1q21-q31 region. Results: The clinica l features of affected members of the five pedigrees presented are gen erally homogeneous. The average age of diagnosis was 18,5 years (range , 5-30 years), and the average initial intraocular pressure was 38.5 m mHg (range, 30-53 mmHg), Eighty-seven percent of affected individuals were myopic and 83% of affected individuals required surgical treatmen t for glaucoma, There were no uniformly associated systemic or ocular conditions, One possible nonpenetrant carrier was identified and a dif ference in phenotypic expression of the presumed disease gene was obse rved in a pair of affected monozygotic twins, We also identified two p edigrees with juvenile glaucoma and three pedigrees affected by the pi gment dispersion syndrome that are not genetically linked to the 1q21- q31 region. Conclusion: The form of juvenile glaucoma caused by a gene located in the q21-q31 region of chromosome 1 is generally phenotypic ally homogeneous. The severe elevation of intraocular pressure typical ly seen in affected patients suggests the product of the predisposing gene may participate in the outflow function of the eye.