Studies of S-adenosylhomocysteine-hydrolase polymorphism in a Croatian population

Recently, a proven case of human S-adenosylhomocysteine-hydrolase (SAHH) deficiency was reported in a Croatian boy. As molecular analysis of the SAHH gene in this case revealed two different mutant alleles, we investigated the polymorphism of human SAHH in a total of 237 red blood samples from unrelated Croats using starch gel electrophoresis and an enzyme-specific staining procedure. From the relative enzymatic activity of SAHH—determined by densitometric assessment of electrophoretic patterns, and calculated on the basis of the protein concentration of the red blood cells—we detected three individuals as being heterozygous for an SAHH 0-allele. Moreover, a total of four different electromorphic SAHHs have been observed, giving allele frequencies calculated as SAHH 1=0.941, SAHH 2=0.032, SAHH 3=0.006, SAHH 4=0.015, and SAHH 0=0.006.