Genetics of the GPT system. Family, mother/child and association studies

GPT types are presented for 150 Norwegian matings, with 454 children, and 1703 Norwegian mother/child combinations. There were five exceptions to a simple codominant inheritance pattern, all believed to be due to a segregating Gpl0‐allele. Rare phenotypes were encountered in two of the families and in 11 of the motherlchild combinations. Compiled family material and mother/child material are presented.No indication of association was found between GPT types and phenotypes within the ABO, Rh, MN, Hp, Gc, C3, PGM1, and ACP1 systems. There is a marked association between EBS‐Ogna (epidermolysis bullosa simplex, type Ogna) affection and GPT phenotypes. This reflects the Gpt‐EBS1 linkage phase. No evidence was found of association between GPT phenotypes and either nephrological diseases or PKU (phenylketonuria).