Adenine for guanine substitution -78 base pairs 5' to the apolipoprotein (APO) A-I gene: relation with high density lipoprotein cholesterol and APO A-I concentrations.

A common mutation, adenine (A) for guanidine (G) substitution (G/A) has been located -78 bp 5' to the apo A-I gene. This region has been shown to be involved in the transcriptional regulation of the apo A-I gene. Previous studies have shown that this mutation is associated with altered high density lipoprotein cholesterol (HDL-C) levels, although these findings have not been consistent. We have studied the frequency of this mutation in 125 subjects (60 males and 65 females) selected because they had HDL-C levels below the 25th (low HDL) or above the 75th (high HDL) percentile of the population distribution. The presence of the mutation was detected by Msp I digestion of a 259 bp fragment of PCR amplified DNA. The allele frequency was similar in both groups (0.20 for the lowest HDL group and 0.28 for the highest HDL group, p > 0.05), although a non-significant trend was observed in a higher frequency of the A/A genotype in the highest HDL females (17.5%) vs only 6.7% in the lowest HDL female group. In conclusion, in this population the G/A mutation was not significantly associated with HDL-C or apo A-I plasma levels.