Current novel-gene-finding strategy for autosomal-dominant hypercholesterolaemia needs refinement

Area of Science:

• Cardiovascular Research
• Genetics
• Molecular Biology

Background:

• Autosomal-dominant hypercholesterolaemia (ADH) is a common, heterogeneous disorder.
• Identifying novel ADH genes is a key focus in cardiovascular research.
• Phenotypic and genetic heterogeneity pose significant challenges to gene discovery.

Purpose of the Study:

• To investigate the impact of phenotypic heterogeneity on identifying new ADH genes.
• To evaluate current diagnostic criteria for ADH in gene discovery efforts.

Main Methods:

• Analysis of 10,000 carriers of APOB/LDLR mutations and 20,000 relatives.
• Evaluation of disease penetrance using plasma cholesterol levels (≥95th percentile) and a penetrance of 0.9.
• Comparison of diagnostic parameters for different mutation types (nonsense vs. missense).

Main Results:

• Current criteria identified causal variants in only 38% of families.
• High penetrance (≥0.9) at the 95th percentile was observed only for LDLR nonsense mutations.
• Lower cholesterol cut-points (75th-90th percentile) are needed for LDLR and APOB missense mutations to achieve high penetrance.

Conclusions:

• Variations in genotype and phenotype for known ADH mutations complicate novel gene identification.
• Current diagnostic criteria and strategies may impede the discovery of new ADH-related genes.
• Revising affected individual assessment and utilizing pedigree/mapping data before exome sequencing is crucial for increasing success rates.