An Indonesian family with the Southeast Asian type of alpha-thalassemia-1 and a gamma-globin gene triplication.

Detailed hematological and fetal hemoglobin data as well as results from gene mapping analyses are reported for nine members of an Indonesian-Dutch family. An alpha-thalassemia-1 heterozygosity (Southeast Asian type) was present in five subjects and a gamma-globin gene triplication of the type-G gamma-G gamma-A gamma in three; the propositus and one of her daughters had both conditions. Comparison of gene mapping data with quantitative results of the fetal hemoglobin analyses provided an explanation for the slight increases in fetal hemoglobin levels and for the extremely high G gamma levels of this fetal hemoglobin.