Novel RPGR mutation with ditinct retiniti pigmentoa phenotype in French-Canadian familie

Purpoe To characterize the molecular defect in two x-linked retiniti pigmentoa (RP) familie. We hypotheized that different RPGR mutation reult in ditinct RP phenotype. Deign Obervational cae erie. Method Fifteen member in family I and three member in family II were evaluated. Full ophthalmic evaluation were done. Linkage analye were performed and likelihood of odd core (LOD core) were calculated. For mutation analye, we ued dHPLC and automated equencing. Reult Two novel RPGR mutation were identified in the two familie; a Glu 414 (2-bp del) framehift mutation in family I and an IV 2–1 (g to a) plice ite mutation in family II. All male family member in family I were everely affected by RP but maintained central viual acuitie until their 50 and did not develop a bull’ eye maculopathy. The female phenotype wa highly variable. ome of the carrier exhibited a evere phenotype, one female diplayed an aymmetric phenotype, and other carrier were aymptomatic. All member with the RPGR framehift mutation exhibited rod-cone electroretinogram abnormalitie, wherea five member had hearing lo. Male member of family II were everely affected, with early viual acuity lo, central cotoma, and bull’ eye maculopathy. The female family member were aymptomatic but diplayed cone-rod electroretinogram change. There wa no hearing lo. Concluion Different RPGR mutation lead to ditinct RP phenotype, with a highly variable inter- and intrafamilial phenotypic pectrum of dieae that i aociated with the type of mutation in RPGR and nonrandom X chromoome inactivation, repectively.