COURSE OF AUTOSOMAL RECESSIVE POLYCYSTIC KIDNEY-DISEASE (ARPKD) IN SIBLINGS - A CLINICAL COMPARISON OF 20 SIBSHIPS

Forty-two children out of 20 sibships with autosomal recessive polycys tic kidney disease were observed pro- and retrospectively over a mean period of 3.7 years in a long-term study on cystic kidney diseases in children. The intra- and interfamilial variability in terms of age at diagnosis, administration of antihypertensive therapy, liver affection , and renal function were evaluated. According to the 1971 subclassifi cation of Blyth and Ockenden, defining different grades of severity, 1 2 patients were assigned to the perinatal, nine to the neonatal, 13 to the infantile, and eight to the juvenile subtype of autosomal recessi ve polycystic kidney disease. In 11 of the 20 families different subty pes were observed among affected siblings. In seven families, affected sibs belonged to adjacent subtypes, while major intrafamilial differe nces were observed in only four families. The defined subtypes, theref ore, cannot be regarded as appropriate in distinguishing genetic group s of autosomal recessive polycystic kidney disease. With respect to th e severity of autosomal recessive polycystic kidney disease, there is a wide spectrum of phenotypic manifestations, ranging from stillbirths to mildly affected adults, while intrafamilial variability of the cli nical picture is generally small with multiple allelism as the most li kely genetic explanation. Age at death, however, showed gross variatio n in eight sibships. Differences in the clinical course between severa l siblings cannot be explained by a sex influence in autosomal recessi ve polycystic kidney disease.