Lysosomal Acid Lipase Deficiency Unmasked in Two Children With Nonalcoholic Fatty Liver Disease.

Lysosomal acid lipase deficiency (LAL-D) is a classic lysosomal storage disorder characterized by accumulation of cholesteryl ester and triglyceride. Although it is associated with progressive liver injury, fibrosis, and end-stage liver disease in children and adolescents, LAL-D frequently presents with nonspecific signs that overlap substantially with other, more common, chronic conditions like nonalcoholic fatty liver disease (NAFLD), metabolic syndrome, and certain inherited dyslipidemias. We present 2 children with NAFLD who achieved clinically significant weight reduction through healthy eating and exercise, but who failed to have the anticipated improvements in aminotransferases and γ-glutamyl transferase. Liver biopsies performed for these "treatment failures" demonstrated significant microvesicular steatosis, prompting consideration of coexisting metabolic diseases. In both patients, lysosomal acid lipase activity was low and LIPA gene testing confirmed LAL-D. We propose that LAL-D should be considered in the differential diagnosis when liver indices in patients with NAFLD fail to improve in the face of appropriate body weight reduction.