We report on five Caucasian patients with congenital polycythemia and mutations of the von Hipple-Lindau (VHL) gene: a compound heterozygote for the novel exon 1 (VHL 235C->T) and previously reported VHL 562C->G mutations; three homozygotes for Chuvash VHL 598C->T mutation; and a heterozygote for VHL 523->G mutation who also has ataxia-telangiectasia; a rare autosomal disease of childhood onset.