The utility of MLPA in Familial Hypercholesterolemia diagnosis

Background: Familial Hypercholesterolemia (FH) is an inherited disease, associated with an increased risk of atherosclerosis, manifested clinically as premature coronary heart disease. FH is biochemically characterized by increased Cholesterol and Low-density Lipoprotein Cholesterol serum levels. The diagnosis is often made using clinical scores however, the definitive FH diagnosis should point out the underlying molecular change, which can be: a point mutation within the three major genes, a number of single nucleotide polymorphisms determining the polygenic etiology, or copy number variations in the Low-density lipoprotein receptor gene.
Objective: In the present study we investigated copy number variations as a possible etiological factor for FH in a cohort of patients with documented premature coronary heart disease.
Methods: The study population consisted of 150 patients with premature coronary heart disease documented by angiography, all being under lipid-lowering therapy, and 20 apparently healthy controls. Serum lipids were assessed using the Cobas Integra 400 plus and commercial reagents. Copy number variations were evaluated with the SALSA MLPA Probemix P062 LDLR kit.
Results: Cholesterol, Triglycerides, Low-density Lipoprotein Cholesterol and High-density Lipoprotein Cholesterol showed no difference between patients and controls. No copy number variations were detected in the investigated regions, namely all 18 exons and the promoter region of the Low-density lipoprotein receptor gene.
Conclusions: Even in the presence of negative results, the Familial Hypercholesterolemia genetic diagnosis has to be further pursued in the presence of a clinical diagnosis, as the identification of the molecular etiology may bring additional clinical and therapeutical benefits, as well as open the possibility for “cascade screening”.