A boy with autosomal recessive hypercholesterolaemia

We describe a 9-year-old Iranian boy with tuberous xanthomas, elevated LDL-cholesterol levels of 15.5 mmol/l, and vague complaints of chest pain while playing soccer. The consanguineous parents of the boy had normal cholesterol concentrations, which indicated an autosomal recessive disorder rather than autosomal dominant familial hypercholesterolaemia. The diagnosis of autosomal recessive hypercholesterolaemia (ARH) was confirmed by the presence of a mutation in the phosphotyrosine binding domain of a putative adaptor protein, which prevents normal internalisation of the LDL receptor (LDLR) in the liver. The clinical phenotype of ARH is similar to that of classical homozygous familial hypercholesterolaemia caused by defects in the LDLR gene, but it is more variable, generally less severe, and more responsive to lipid-lowering therapy. The patient's complaints of chest pain were not caused by ischaemia as was tested by an exercise and 24-hour electrocardiogram and by a myocardial perfusion scan. His LDL-C dropped by about 6o% after being treated with a combination of 40 mg atorvastatin and 10 mg ezetimibe.