Purpose: To document the progression of disease in male and female members of a previously described family with X-linked dominant retinitis pigmentosa (RP) caused by a de novo insertion after nucleotide 173 in exon ORF15 of RPGR.
Methods: The clinical records of 19 members of family UTAD054 were reviewed. Their evaluations consisted of confirmation of family history, standardised electroretinograms (ERGs), Goldmann visual fields, and periodic ophthalmological examinations over a 23-year period.
Results: Male members of family UTAD054 had non-recordable to barely recordable ERGs from early childhood. The males showed contracted central fields and developed more severe retinopathy than the females. The female members showed a disease onset delayed to teenage years, recordable but diminishing photopic and scotopic ERG amplitudes in a cone-rod pattern, progressive loss and often asymmetric visual fields, and diffuse atrophic retinopathy with fewer pigment deposits compared with males.
Conclusions: This insertion mutation in the RPGR exon ORF15 is associated with a RP phenotype that severely affects males early and females by 30 years of age, and is highly penetrant in female members. Families with dominant-acting RPGR mutations may be mistaken to have an autosomal mode of inheritance resulting in an incorrect prediction of recurrence risk and prognosis. Broader recognition of X-linked RP forms with dominant inheritance is necessary to facilitate appropriate counselling of these patients.