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.
Diagnosis
Blood tests may show anaemia and their lipid profiles are generally similar to people with more common familial hypercholesterolemia, including elevated total cholesterol, elevated low-density lipoprotein cholesterol, decreased high-density lipoprotein cholesterol and elevated serum transaminases.Liver biopsy findings will generally show a bright yellow-orange color, enlarged, lipid-laden hepatocytes and Kupffer cells, microvesicular and macrovesicular steatosis, fibrosis, and cirrhosis. The only definitive tests are genetic, which may be conducted in any number of ways. Screening
Because LAL deficiency is inherited, each sibling of an affected individual has a 25% chance of having pathological mutations in LAL genes from both their mother and their father, a 50% chance of having a pathological mutation in only one gene, and a 25% chance of having no pathological mutations. Genetic testing for family members and genetic prenatal diagnosis of pregnancies for women who are at increased risk are possible if family members carrying pathological mutations have been identified. Management
LAL deficiency can be treated with sebelipase alfa is a recombinant form of LAL that was approved in 2015 in the US and EU. The disease of LAL affects < 0.2 in 10,000 people in the EU. According to an estimate by a Barclays analyst, the drug will be priced at about US$375,000 per year.It is administered once a week via intraveneous infusion in people with rapidly progressing disease in the first six months of life.