Foetal macrosomia and erythrocyte acid phosphatase (ACP1) polymorphism in diabetic and normal pregnancy.

Both in diabetic and in normal pregnancy the proportion of macrosomic fetuses is much lower among newborns carrying Pc allele of erythrocyte acid phosphatase (ACP1) than among other ACP1 genotypes. In diabetic pregnancy the well known increased incidence of fetal macrosomia has been observed only among fetuses which do not carry this allele. ACP1 probably functions as a flavin-mononucleotide phosphatase. Since Pc allele is associated with the highest enzymatic activity it is likely that subjects carrying this gene may have a relatively lower concentration of flavin-mononucleotide cofactors and in turn a reduced rate of metabolic activities controlled by flavoenzymes. It is possible that in fetuses carrying Pc, flavo-enzyme activities are regulated at a level that does not allow a full response to stimuli (both genetic and/or environmental) aimed to maximize fetal growth.