Lysosomal acid lipase deficiency: Diagnosis and treatment of Wolman and Cholesteryl Ester Storage Diseases

Abstract

Lysosomal acid lipase (LAI) is responsible for the hydrolysis of cholesterol esters and triglycerides. LAL is coded by the LIPA gene on chromosome 10q23.31. Its deficiency leads to two autosomal recessive disorders, Wolman disease (WD) and Cholesteryl Ester Storage Disease (CESD). WD has an estimated incidence of 1 in 500,000 live births and is the result of a complete loss of LAL and presents in infancy with vomiting, diarrhea, poor weight gain and hepatomegaly subsequently leading to death. CESD is the result of partial loss of LAL and its presentation is more variable. Patients may be asymptomatic or present with nonspecific gastrointestinal symptoms, hepatomegaly, elevated transaminases and dyslipidemia which may be confused with the diagnosis of Non-alcoholic Fatty Liver Disease. CESD is currently underdiagnosed and has an estimated prevalence as high as 1 in 40,000 individuals. Radiologic findings in WD is calcification of the adrenal glands. Hepatomegaly is noted on CT scan in both WD and CESD. MRI may demonstrate accumulation of cholesterol esters and may be useful to study effects of potential medical therapies. The diagnosis of WD and CESD is based on LIPA gene sequencing and the measurement of LAL levels in peripheral blood leukocytes. Treatment of LAL deficiency is currently limited to control of cholesterol levels and to prevent premature atherosclerosis. Use of enzyme replacement therapy with recombinant human LAL in short-term studies has shown to be safe and effective.