CONGENITAL NEPHROTIC SYNDROME OF THE FINNISH TYPE - LINKAGE TO THE LOCUS IN A NON-FINNISH POPULATION

Congenital nephrotic syndrome of the Finnish type (CNF) is inherited a s an autosomal recessive trait. The biochemical basis of the disease i s unknown, although a lesion in the glomerular basement membrane is st rongly suggested. Recently, the CNF locus was assigned to chromosome 1 9q12-q13.1 on the basis of linkage analysis in Finnish families. The h igh incidence of the disease in Finland, as well as the demonstration of linkage disequilibrium in the Finnish study, strongly suggests a fo under effect based on a common ancient mutation in this population. We confirm linkage of the CNF locus to the same chromosomal region in se ven non-Finnish CNF families without evidence of linkage disequilibriu m. Our results show that the same gene seems to be affected in both Fi nnish and non-Finnish CNF populations. However, in the latter the muta tion-carrying chromosomes descend from different ancestors without evi dence of a founder effect.