Study of the genetic variability of ZAC1 (PLAGL1) in French population-based samples

ZAC1 (zinc finger protein regulating apoptosis and cell cycle arrest) is a member of the new subfamily of zinc-finger transcription factors, designated as PLAG (pleomorphic adenoma gene) family. The ZAC1 gene is maternally imprinted and is linked to developmental disorders such as growth retardation and transient neonatal diabetes mellitus. We wanted to assess whether the genetic variability of the ZAC1 gene was associated with anthropometric (weight, BMI, waist-to-hip ratio) or biochemical (plasma lipid, insulin, glucose levels, blood pressure level) phenotypes.

We selected 37 independent SNPs (single nucleotide polymorphisms) or tagSNPs in the ZAC1 locus from the literature and several databases and, based on the linkage disequilibrium map, identified 27 independent SNPs. Those 27 SNPs were genotyped in a French population-based sample (n = 1155). Associations with a P value lower than 0.0019 (Bonferroni correction) were considered significant.

We found that women carrying the T allele of rs9403542 had lower waist-to-hip ratio (P = 0.0006) than women with the CC genotype. Also, men bearing the T allele of rs13218225 had lower systolic (P = 3.6 x 10(-5)) and diastolic (P = 4.1 x 10(-4)) blood pressure than GG men. As a consequence, the adjusted (for age, smoking habit, alcohol consumption, physical activity level and BMI) odds ratio (95% confidence interval) of hypertension for T allele carrier men was 0.55 [0.35-0.86], P = 0.009. We genotyped two other independent samples (MONICA Toulouse, n = 1130 and MONICA Strasbourg, n = 1048) for rs9403542 and rs13218225 but we could not confirm these associations.

We found no evidence that polymorphisms in ZAC1 might influence anthropometric, biochemical or clinical parameters in French individuals.