Genome-wide linkage and association scans for quantitative trait Loci of serum lactate dehydrogenase-the framingham...

Serum lactate dehydrogenase (LDH) is used in diagnosing many diseases and is significantly determined by genetic factors. Three genes coding for LDH isoenzymes were mapped to chromosome 11q15 and 12p12. We used 330 Framingham Heart Study largest families for microsatellite linkage scan and 100K SNPs association scan to determine quantitative trait loci of LDH level. We estimated the heritability at 41%. Our genome-wide linkage analysis yielded several chromosomal regions, other than 11q and 12p, with LOD scores between 1 and 2.5. None of the 100K SNPs with a P-value <10(-4) in our genome-wide association study was close to the chromosomal regions where the LDH genes reside. Our study demonstrated a strong genetic effect on the variation of LDH levels. There may not be a single gene with a large effect, instead may be several genes with small effects in controlling the variation of serum LDH. Those genes may be located on chromosomal regions that differ from where the genes encoding LDH isoenzymes reside.