[Idiopathic hemochromatosis linkage with the HLA system (author's transl)].

Fourteen selected families containing two or more subjects suffering from idiopathic hemochromatosis and 34 unrelated cases have been studied for their HLA markers. A 3 was present in 75% of the unrelated cases vs 26% in the normal population (p less than 10(-8)). The frequencies of B 7 (38% vs 19%) and B 14 (23% vs 9%) were also increased (p lessthan 0,05). Inevitably, in most cases both antigens in the B locus were associated with A 3. Seven of nine affected sib pairs shared both HLA haplotypes, while two shared only one. Significant association between HLA haplotypes and diseases segregation has been demonstrated in family studies. These facts are consistent with the recessive inheritance of a strongly A 3 linked "disease" gene responsible for abnormal iron stores in the heterozygote state. This hypothesis would account for 64% of our present cases. Most of discordances (26%) were females who are physiologically protected, or children under 17 who might later develop the disease. The remaining 10% of disordant cases could be explained by crossing-over between "disease" gene and HLA loci or by an heterogeneity of the disease. This provides a method for screening for high risk subjects and perhaps an opportunity for anticipatory prevention.