Recommendations for LDLR variant interpretation by the ClinGen’s Familial Hypercholesterolemia Expert Panel

Familial Hypercholesterolemia (FH): - Lipid metabolism autosomal dominant condition; - Elevated low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) values since childhood → increased risk of atherosclerotic cardiovascular disease; - High heterozygote prevalence (1/250-1/500); Homozygous rare (1/ 300 000- 1/ 1 000 000); - Caused by pathogenic variants in LDLR (>90%), APOB (5- 10%) and PCSK9 (1-3%) genes; -Marked increase in FH variants submitted to ClinVar; -45% of variants were classified with more than one method and 466 variants submitted with potential clinical significance had conflicting or no classifications.