Concept
Lysosomal acid lipase deficiency (LAL deficiency or LAL-D) is an autosomal recessive inborn error of metabolism that results in the body not producing enough active lysosomal acid lipase (LAL) enzyme. This enzyme plays an important role in breaking down fatty material (cholesteryl esters and triglycerides) in the body. Infants, children and adults that have LAL deficiency experience a range of serious health problems. The lack of the LAL enzyme can lead to a build-up of fatty material in a number of body organs including the liver, spleen, gut, in the wall of blood vessels and other important organs. Very low levels of the LAL enzyme lead to LAL deficiency. LAL deficiency typically affects infants in the first year of life. The accumulation of fat in the walls of the gut in early onset disease leads to serious digestive problems including malabsorption, a condition in which the gut fails to absorb nutrients and calories from food. Because of these digestive complications, affected infants usually fail to grow and gain weight at the expected rate for their age (failure to thrive). As the disease progresses, it can cause life-threatening liver dysfunction or liver failure. Until 2015, there was no treatment, and very few infants with LAL-D survived beyond the first year of life. In 2015, an enzyme replacement therapy, sebelipase alfa, was approved in the US and EU. The therapy was additionally approved in Japan in 2016. Infants may present with feeding difficulties with frequent vomiting, diarrhea, swelling of the abdomen, and failure to gain weight or sometimes weight loss. As the disease progresses in infants, increasing fat accumulation in the liver leads to other complications including yellowing of the skin and whites of the eyes (jaundice), and a persistent low-grade fever. An ultrasound examination shows accumulation of chalky material (calcification) in the adrenal gland in about half of infants with LAL-D.