High prevalence of PRPH2 in autosomal dominant retinitis pigmentosa in france and characterization of biochemical and clinical features.

PURPOSE: To assess the prevalence of PRPH2 in autosomal dominant retinitis pigmentosa (adRP), to report 6 novel mutations, to characterize the biochemical features of a recurrent novel mutation, and to study the clinical features of adRP patients. DESIGN: Retrospective clinical and molecular genetic study. METHODS: Clinical investigations included visual field testing, fundus examination, high-resolution spectral-domain optical coherence tomography (OCT), fundus autofluorescence imaging, and electroretinogram (ERG) recording. PRPH2 was screened by Sanger sequencing in a cohort of 310 French families with adRP. Peripherin-2 protein was produced in yeast and analyzed by Western blot. RESULTS: We identified 15 mutations, including 6 novel and 9 previously reported changes in 32 families, accounting for a prevalence of 10.3% in this adRP population. We showed that a new recurrent p.Leu254Gln mutation leads to protein aggregation, suggesting abnormal folding. The clinical severity of the disease in examined patients was moderate with 78% of the eyes having 1-0.5 of visual acuity and 52% of the eyes retaining more than 50% of the visual field. Some patients characteristically showed vitelliform deposits or macular involvement. In some families, pericentral RP or macular dystrophy were found in family members while widespread RP was present in other members of the same families. CONCLUSIONS: The mutations in PRPH2 account for 10.3% of adRP in the French population, which is higher than previously reported (0%-8%) This makes PRPH2 the second most frequent adRP gene after RHO in our series. PRPH2 mutations cause highly variable phenotypes and moderate forms of adRP, including mild cases, which could be underdiagnosed

Microspherophakia-metaphyseal dysplasia: a 'new' dominantly inherited bone dysplasia with severe eye involvement.

We report a father and son affected by a hitherto unpublished bone dysplasia with moderately severe dwarfism. On initial radiographs, thickening of the diaphyses of the long bones was striking. The small bones of the extremities were almost unaffected. With age, the metaphyseal deformation became more prominent. The epiphyses became irregular and their growth was delayed (particularly the femoral heads). The femoral neck showed an unusual 'lip' on the inner edge. Later, the stubby appearance of the long bones faded and, in adulthood, only enlarged metaphyses and deformed femoral necks persisted. The vertebrae showed moderate deformation with irregular flattening, and narrowing of the spinal canal with a shortened interpedicular distance. The eye defects consisted of high grade myopia, microspherophakia, lens coloboma, lens luxation, and retinal detachment. The name 'microspherophakia-metaphyseal dysplasia' is suggested for this probably autosomal dominant bone dysplasia