People with familial low HDL, or hypolipoproteinemia, have an impaired ability to transport cholesterol out of their cells, which leads to an accumulation of cholesterol in many tissues. For some of these individuals, the disease is due to mutations in proteins called ATP-binding cassettes (ABCs) that transport lipids and other molecules inside and outside cells, but for many affected individuals, the causes of the disease is still not well known.
Marja-Riitta Taskinen and colleagues examined how the first steps of the transport of cholesterol into the liver were disturbed in individuals with familial low HDL. The scientists compared the gene expression of ABC proteins in low HDL and control subjects and found that the genetic expression of ABC proteins was increased in low HDL subjects, indicating that these ABC proteins may be abnormally produced in the affected individuals. -American Society for Biochemistry and Molecular Biology