A common deletion in the haptoglobin gene associated with blood cholesterol levels among Chinese women

Haptoglobin (HP) protein plays a critical role in binding and removing free hemoglobin from blood. A deletion in the HP gene affects the protein structure and function. A recent study developed a novel method to impute this variant and discovered significant association of this variant with low-density lipoprotein (LDL) and total cholesterol levels among European descendants. In the present study, we investigated this variant among 3608 Chinese women. Consistent with findings from Europeans, we found significant associations between the deletion with lower cholesterol levels; women homozygous for the deletion allele (HP1-HP1), had a lower level of total cholesterol (-4.24 mg dl(-1), P = 0.02) and LDL cholesterol (-3.43 mg dl(-1), P = 0.03) than those not carrying the deletion allele (HP2-HP2). Especially, women carrying the HP1S-HP1S, had an even lower level of total cholesterol (-5.59 mg dl(-1), P= 7.0 x 10(-3)) and LDL cholesterol (-4.68 mg dl(-1), P= 8.0 x 10(-3)) compared to those carrying HP2-HP2. These associations remained significant after an adjustment for an established cholesterol level-related variant, rs2000999. Our study extends the previous findings regarding the association of HP structure variant with blood cholesterol levels to East Asians and affirms the validity of the new methodology for assessing HP structure variation.