Aim: To make qualitative and quantitative analyses of phenotypical characteristics and to study a spectrum and frequency of mutations in LDLR and APOB genes in patients with familial heterozygous hypercholesterolemia (FHHC).
Material and methods: Clinical symptoms of FHHC were studied in males and females. Mutations were detected with PCR, analysis of SSCP of all the exones of LDLR gene and a fragment of exone 26 of APOB gene with subsequent sequestration of DNA fragments with anomalous electrophoretic motility, analysis of restriction fragments length polymorphism.
Results: LDLR gene mutations were detected in 50%, of APOB gene in 2.6% patients with FHHC, 70% of LDLR gene mutations have never been discovered before. Three known mutations were detected in the APOB gene: R3500Q (1.9% cases), H3543Y (0.55%), R3531C (0.15%). Incidence of coronary heart disease in untreated FHHC patients is 61.5%, of myocardial infarction--31%. Life span of both males and females with FHHC was subnormal, especially of men (median: 53 years in 95% CI, 49.2-56.8 years and 62 years in 95% CI 59.2-64.8 years, respectively). Incidence rate of basic clinical symptoms increased with age and significantly correlated with LDLP cholesterol.
Conclusion: Frequency and severity of clinical symptoms and complications in FHHC and in Russian population agree with those of the European countries. The same occurs with frequency and mutations of the APOB gene, while mutations of the LDLR gene in 70% cases are unique for Russian population and are not described in other countries. This makes impossible to use foreign test kits for FHHC diagnosis in Russia.