title: [A family with an "Hm" phenotype transmitted over 3 generations].
abstract: Hm phenotype represents a dissociation between a normal salivary expression of H substance and a very weakened expression of the antigen on red blood cells. Genetic analysis of the reported family reveals a dominant inheritance: Some members (Marie K..., Francette, Carmen) present a phenotype marked by a normal H enzyme but a deficient H antigen in erythrocyte membrane. Others Alice, Mathilde) have no expression of A1 antigen due to H substrate deficiency. H substance in salivary secretion is normal. In the other branch of this pedigree without consanguinity, Herbert presents an H substance deficiency, though quite different, as A1 antigen is expressed. In this family, Hm phenotype can be explained, without resorting to a Zm allele, by the expression of an exceptional allele at the H locus (like Am is an ABO allele). This hypothesis supports the possible polymorphism of H locus.
mesh_terms: D000017:ABO Blood-Group System; D001666:Binding Sites, Antibody; D005260:Female; D006801:Humans; D008297:Male; D010375:Pedigree; D010641:Phenotype; D011110:Polymorphism, Genetic; D012463:Saliva / Q000276:immunology
chemical_list: D000017:ABO Blood-Group System
vernacular_title: Une famille où un phénotype "Hm" est transmis à travers trois générations.