METHODS

Patients: We previously mapped the adRP locus on chromosome 19q13. 4 and identified several adRP families linked to this locus [3, 4]. After subsequent cloning of the PRPF31 gene mutations were identified in all but one family referred to as ADRP2. Patients from this family were the subjects of this study. The study protocol was approved by the hospital ethics committee and was in accordance with the tenets of the Declaration of Helsinki (June 1964); informed consent was obtained from all members after explanation of the nature and possible consequences of the study. Although DNA of more than 17 members (disease status known) of this three-generation British family is available, only seven members were available for ophthalmic reexamination. The youngest patient examined was 11 years of age and the oldest 47. A detailed history was taken, focussing on the typical signs of RP and their