Kawano S

Multicenter genetic study of retinitis pigmentosa in Japan: I. Genetic heterogeneity in typical retinitis pigmentosa☆

A nationwide, multicenter study of typical retinitis pigmentosa (RP) was carried out in collaboration with 18 hospitals throughout Japan to obtain current information for genetic counseling. We analyzed the genetic heterogeneity of RP based on the parental consanguinity of 434 probands registered during a 6-month period in 1990. A gradual decline in the frequency of consanguineous marriage was recognized among the normal parents of RP patients. The relative frequencies of inheritance patterns were estimated as: autosomal recessive, 25.2%; autosomal dominant, 16.9%; X-linked, 1.6%; and simplex, 56.3%. A comparison of these results with previous reports in Japan revealed a decline in the relative frequency of autosomal recessive cases and an increase in simplex cases. This suggests a decrease in the incidence of autosomal recessive retinitis pigmentosa in Japan, as well as the necessity for exhaustive investigations aimed at identifying inheritance patterns for RP patients seeking genetic counseling.

Multicenter genetic study of retinitis pigmentosa in Japan: II. Prevalence of autosomal recessive retinitis pigmentosa

Retinitis pigmentosa (RP) is a group of genetically heterogeneous diseases with autosomal recessive (AR), autosomal dominant, and X-linked modes of inheritance. Autosomal recessive retinitis pigmentosa (ARRP) is the most common form in Japan. A genetic analysis was done to determine the prevalence of ARRP indirectly, to provide an estimation of changing trends in the overall prevalence of RP. Data on the frequency of consanguinity and marriage year of normal parents of 59 ARRP patients were obtained from a nationwide multicenter survey of typical retinitis pigmentosa conducted in 1990. The gene frequency of ARRP was 0.01145 (Dahlbergs formula). In 1990, the number of young symptomatic ARRP patients decreased, while the number of patients aged 40 years and older increased. The total number of symptomatic ARRP patients in 1990 was nearly 21% higher than in 1970. Despite a dramatic decline in consanguinity in recent decades in Japan, the number of ARRP patients has increased. This increase is attributed to greater longevity and overall population growth. Our results suggest that the total number of RP patients has not decreased, and may even have increased.

Four cases of late infection following scleral buckling procedure

We report four cases with late infection following a scleral buckling procedure. These cases were a 44-year-old male, a 52-year-old female, a 59-year-old male, and a 60-year-old male. All of these cases developed conjunctival injection, chemosis, and mucopurulent discharge 7 to 15 years after the procedure. The symptoms did not improve despite months of medical therapy, suggesting scleral buckle infection, and finally the buckling materials were removed. Solid silicone was used in 2 cases, and a sponge was used in 2 cases, with encircling elements in 1 case, and without encircling elements in 3 cases. Pus culture of the removal exoplant revealed fungaul infection in 2 cases. The others were negative, but bacterial infection was suspected from their clinical course and intraoperative findings. After removal of the buckles, the symptoms improved rapidly in all cases and there was no recurrence of retinal detachment. Scleral buckle infection should be suspected and removal of buckling materials should be considered, in cases with refractory conjunctival and scleral inflammation even years after scleral buckling procedure.