A MULTICENTER STUDY OF TYPICAL RETINITIS-PIGMENTOSA IN JAPAN

A nationwide, multicenter study of typical retinitis pigmentosa was ca rried out in collaboration with 13 university hospitals throughout Jap an. A total of 253 patients, 122 males and 131 females, with a wide ra nge of ages (mean 48 years), were registered during a two-month period in 1989. Determination of inheritance pattern revealed 30.2% autosoma l recessive cases, 15.4% autosomal dominant, 0.5% X-linked, and 48.9% simplex, indicating a relative decrease in autosomal recessive cases a nd a relative increase in simplex cases in recent decades. The age at onset, initial symptom, and visual functions including visual acuity, visual field and electroretinogram showed a marked interindividual var iability, but statistical analysis demonstrated that visual defects pr ogressed with increasing age and disease duration. A correlation betwe en the phenotypic variation and the genetic type was observed. This su rvey of retinitis pigmentosa in Japan provides information for counsel ing and rehabilitation of patients and encourages basic and clinical r esearch of this genetic disease.