Spectrum of mutations in the HFE gene implicated in haemochromatosis and porphyria

Abstract

Mutation analysis was performed on DNA samples of 965 individuals from four different ethnic groups in South Africa, in an attempt to determine the spectrum of sequence variants in the haemochromatosis (HFE) gene. This population screening approach, utilizing a combined heteroduplex and single-strand conformation polymorphism (HEX-SSCP) method, revealed three previously described and four novel missense mutations. Novel variants V53M and V59M were identified in exon 2, Q127H in exon 3 and R330M in exon 5. The exon 5 variant was identified in one of 13 patients referred for a molecular diagnosis of hereditary haemochromatosis (HH), who tested negative for the known C282Y and H63D mutations. Mutation Q127H was detected in exon 3 of the HFE gene together with mutation H63D in an apparently severely affected patient previously shown to carry the protoporphyrinogen oxidase (PPOX) gene mutation R59W, which accounts for dominantly inherited variegate porphyria (VP) in > 80% of affected South Africans. The mutant allele frequency of the C282Y mutation was found to be significantly lower in 73 apparently unrelated VP patients with the R59W mutation than in 102 controls drawn from the same population (P = 0.005). The population screening approach used in this study revealed considerable genotypic variation in the HFE gene and supports previous data on the involvement of this gene in the porphyria phenotype.