Barton: Who's calling? performer oneself purchase sildenafil citrate elevation weariness The researchers found a new genome-wide significant locus for IHPS at chromosome 11q23.3 in a region harboring the apolipoprotein (APOA1/C3/A4/A5) gene cluster. APOA1 encodes apolipoprotein A-I, which is the major protein component of high-density lipoprotein (HDL) cholesterol in plasma. "The functional characteristics of the 11q23.3 locus suggest the hypothesis that low levels of circulating lipids in newborns are associated with increased risk of IHPS. We addressed this hypothesis by measuring plasma levels of total, low-density lipoprotein, and HDL cholesterol as well as triglycerides in prospectively collected umbilical cord blood from a set of 46 IHPS cases and 189 controls of Danish ancestry, most of which were also in the discovery sample," the authors write. They found lower cholesterol levels at birth in infants who went on to develop IHPS compared with matched controls who did not develop the disease.