FREQUENCY AND IMPACT OF AUTOSOMAL-DOMINANT POLYCYSTIC KIDNEY-DISEASE IN THE SEYCHELLES (INDIAN-OCEAN)

Background. As little such data is available in African populations, w e investigated the prevalence of ADPKD and the impact of the disease i n the Seychelles islands, where approximately 65% of the population is of African descent and 30% of Caucasian or mixed descent. Methods. Pr evalent cases were identified over a 3-year period by requesting all t he doctors in the country (most of them are employed within a national health system) to refer all presumed or confirmed cases and by system atically examining the family members of all confirmed cases. The diag nosis was based on standard criteria including ultrasonographic findin gs and family history. Results. Forty-two cases were identified in thi s population of 74331 inhabitants, a total prevalence (per 100000 tota l population) of 57 (95% CI, 41-76). All but one of the cases were of Caucasian descent so that the prevalence rates of the disease in the p opulations of Black and Caucasian descents were respectively 2 (0-11) and 184 (132-249). The prevalence rates of the gene(s) carriers were e stimated to be 75 (45-117) in the total population respectively 6 (0-3 3) and 236 (140-372) in the Black and Caucasian populations. Haplotype analysis in 58 cases from three families showed a common DNA fragment in all affected individuals. Cases had significantly higher blood pre ssure compared to the general population and 21% had serum creatinine higher than 120 mu mol/l. Among the established pedigrees, mean age of death between 1960 and 1995 (haemodialysis was introduced in 1992) wa s younger in subjects with than those without ADPKD (50.5 vs 67.7 year s; P<0.001). Conclusions, In the Seychelles, ADPKD clusters in the Cau casian population (possibly a founder effect), is rare in individuals of black descent, and is associated with substantial clinical and surv ival impact.