Linkage and association of the sodium potassium-adenosine triphosphatase (alpha 2 and beta 1 genes with respiratory quotient and resting metabolic rate in the Quebec Family Study

The purpose of this study was to examine the relationship between the alpha 2 (exon 1 and exon 21-22 with BglII) and beta 1 (MspI and PvuII) genes of the sodium potassium adenosine triphosphatase and resting metabolic rate (R MR) and respiratory quotient (RQ). The sample included 582 participants fro m 171 families of the Quebec Family Study. RMR and RQ were adjusted for age , sex, fat mass, and fat free mass. Sib-pair analyses indicated a significa nt linkage between RQ and the alpha 2 exon 1 marker (P = 0.03) and the alph a(2) exon 21-22 marker (P = 0.02). No linkage was detected between the beta 1 markers and either RMR or RQ, whereas RMR was not linked with the alpha 2 makers. There was a significant interaction (P < 0.0003) between alpha 2 exon 1 carrier status and age group [younger (<45 yr) us. older (greater th an or equal to 45 yr) adults] for RQ. The association between carrier statu s and RQ was significant in younger adults (RQ = 0.76 in carriers us. 0.80 in noncarriers, P < 0.0001) but was not in older adults (RQ = 0.81 in carri ers vs. 0.80 in noncarriers). The alpha 2 exon 1 gene accounted for approxi mately 9.1% and 0.3% of the variance in RQ in younger and older adults, res pectively. The results suggest that the sodium potassium adenosine triphosp hatase alpha 2 gene may play a role in fuel oxidation, particularly in youn ger individuals.