APOA1 and hypoalphalipoproteinemia, primary, 1: Some allelic variants of the APOA1 gene (homozygous, heterozygous, or compound heterozygous genotype) cause familial hypoalphalipoproteinemia AD (hypoalphalipoproteinemia, Primary, 2, OMIM 618463), which includes two autosomal recessive diseases: the combined deficiency of Apo-I and apoC-III (ApoA-I and apoC-III deficiency, combined) [14,34].