Association between SAH, an acyl-CoA synthetase gene, and hypertriglyceridemia, obesity, and hypertension

The SA gene (SAH) has been isolated by differential screening from a genetically hypertensive rat strain as a candidate gene that may contribute to hypertension. Recently, the SA protein has been reported to be highly homologous to bovine xenobiotic-metabolizing medium-chain fatty acid:CoA ligase.

To clarify the pathophysiological significance of SAH, we searched for polymorphisms of human SAH and performed association studies using a large cohort (4000 subjects) representing the general population in Japan. We found 2 polymorphisms in the promoter region and single-nucleotide polymorphisms in introns 5, 7, and 12 and exon 8. One of the variants, an A/G polymorphism in intron 12, just 7 bp upstream from exon 13, strongly affected plasma triglyceride, plasma cholesterol, body mass index (BMI), waist-to-hip ratio (W/H), and blood pressure status. The effect of this genotype on blood pressure seems to be conveyed through its effects on BMI and W/H. Transient expression of the SA protein in mammalian cells confirmed that it is expressed in mitochondria and has medium-chain fatty acid:CoA ligase activity. The A/G polymorphism was found to be associated with the expression level of SA mRNA in peripheral mononuclear cells in vivo.

The G allele of SAH was found to be associated with multiple risk factors, including hypertriglyceridemia, hypercholesterolemia, obesity, and hypertension. This observation should open a new area for future research in multiple-risk-factor syndromes.