Combined hyperlipidaemia as a presenting sign of cholesteryl ester storage disease

Abstract

Lysosomal acid lipase (LAL) deficiency results in Wolman disease and cholesteryl ester storage disease (CESD), a more benign form. CESD is a recessive disorder characterized by hypercholesterolaemia, hypertriglyceridaemia, low blood HDL and variable phenotype, while hepatomegaly is usually evident during childhood or adolescence. An 11-year-old girl was referred to our department for combined hyperlipidaemia (total cholesterol 323, triglycerides 259 mg/dl). All family members had normal lipid profile and liver function tests. At 8 years she was admitted for acute Epstein-Barr virus infection, with hepatosplenomegaly and elevation of liver enzymes. Liver-spleen enlargement resolved, but serum alanine aminotransferase and aspartate aminotransferase were persistently twice the upper limits, with other liver function tests within the normal range. Ultrasonography showed normal liver and spleen size and minimal hepatic steatosis. Infectious, autoimmune and metabolic causes of elevated liver enzymes were ruled out, including glycogen storage disease. Dysbetalipoproteinaemia was also ruled out (ApoE phenotype: E3E3). In the following 2 years the girl was symptom-free, BMI was at the 50th-75th centile for age and lipid profile was unchanged despite a low-fat diet. At 13 years of age, low acid lipase activity was demonstrated in leukocytes (10 nmol/h/ per mg protein, normal 140-380) and cultured skin fibroblasts (181 nmol/h per mg protein, normal 1100-2400), leading to diagnosis of CESD. CESD usually progresses to hepatic fibrosis, with high risk of premature atherosclerosis. CESD prevalence may be underestimated in the general population. The diagnosis may be considered in all subjects with atypical combined hyperlipidaemia (usually dominant in transmission or related to metabolic syndrome) and atypical 'fatty liver disease', in the absence of overweight.