Familial combined hyperlipidaemia linked to the apolipoprotein AI-CIII-AIV gene cluster on chromosome 11q23-q24

Familial combined hyperlipidemia (FCHL) is an inherited disorder of fat metabolism that causes as many as 10 percent of the cases of premature disease of the coronary arteries, which supply the heart with blood. One fifth of the patients with FCHL develop premature coronary heart disease. FCHL sufferers have elevated blood cholesterol and/or triglyceride levels, as well as abnormal low-density lipoproteins (forms in which fats are carried in the blood). To better characterize the gene defect associated with FCHL, members of eight FCHL families were studied. Techniques of DNA analysis and linkage analysis were used to identify the gene cluster associated with FCHL in the families evaluated. It was found to be the AI-CIII-AIV gene cluster, which contained the X2 allele in half the affected families. This region appears to carry a genetic defect that causes a metabolic disorder that in turn predisposes the individual to develop premature coronary heart disease. Further research is needed to identify the mutation present in people at risk. (Consumer Summary produced by Reliance Medical Information, Inc.)