Mutation of one VHL allele.

(A) Sequencing of the second exon of the VHL gene of patients 1 and 2 and their parents. The 376G>T (Asp126Tyr)VHL mutation found in patients 1 and 2 was inherited from the father. The father was not polycythemic, but his BFU-Es were hypersensitive to Epo. (B) 376T mutation analysis by a PCR-based discrimination assay with allele-specific fluorescent probes. PCR of the normal G376 allele leads to the release of the VIC fluorescent label, whereas the mutated T376 allele leads to the release of the 6-FAM fluorescent label. Controls (○); patients 1 and 2 and their father (▴); PCR without a DNA template (■). Our results confirm the heterozygosity for the G376Thr mutation in patients 1 and 2 and their father, and indicate that none of the 177 healthy controls have the mutated T376 allele.