|
|
Wolman disease (also known as Wolman’s disease, Wolman’s syndrome, and acid lipase deficiency) is a rare severe lipid storage disease that is usually fatal by age 1. This autosomal recessive disorder is marked by accumulation of cholesteryl esters (normally a transport form of cholesterol) and triglycerides (a chemical form in which fats exist in the body) that can build up significantly and cause damage in the cells and tissues. Both males and females are affected by this severe disorder. Infants are normal and active at birth but quickly develop progressive mental deterioration, hepatosplenomegaly (enlarged liver and grossly enlarged spleen), distended abdomen, gastrointestinal problems including steatorrhea (excessive amounts of fats in the stools), jaundice, anemia, vomiting and calcium deposits in the adrenal glands, causing them to harden. There is no specific treatment for Wolman disease. Patients with anemia may require blood transfusions. In some patients, the enlarged spleen must be removed to improve cardiopulmonary function. Restricting one’s diet does not prevent lipid buildup in cells and tissues. Wolman disease, also known as lysosomal acid lipase disease, is a lethal genetic disorder caused by the lack of the enzyme lysosomal acid lipase. Lysosomal acid lipase is a cellular enzyme widespread throughout the body. It is important in the breakdown of certain body lipids called triglycerides and cholesteryl esters. Individuals without active enzyme accumulate abnormally large amounts of these lipids in their cells. This build-up interferes with the normal metabolic functions of the cells and leads to severe neurological and physical symptoms and early death. A milder disease, cholesteryl ester storage disease (CESD), is caused by mutations in the same gene, but affected individuals may not show symptoms until adulthood.
Inheritance pattern Wolman disease is an autosomal recessive disorder affecting both males and females. In individuals with this disorder, both copies of the gene that codes for lysosomal acid lipase are abnormal. Both parents of an affected child have one abnormal copy of the gene, but usually do not show symptoms because they also have one normal copy. The normal copy provides approximately 50% of the usual enzyme activity, a level adequate for the body's needs. Individuals with one abnormal copy of the gene and 50% enzyme activity are said to be carriers or heterozygotes. Because both parents of a child with Wolman disease are carriers, they have a 25% risk in each subsequent pregnancy of having another child who is affected with the same disorder. Symptoms of Wolman disease appear in the first few weeks of life. Forceful vomiting and distention of the abdomen usually alert parents to a problem. Other general symptoms in the early stages of this disease are watery diarrhea or fat in the stools, fever, and a yellow tint to the skin (jaundice). Medical examination reveals massive enlargement of the liver and spleen (hepatosplenomegaly) due to a build-up of fats that cannot be broken down. Other common findings are severe anemia, calcium deposits in the adrenal glands, and a general decline in mental development. Diagnosis Diagnosis can be difficult because there are no general laboratory tests that point specifically to Wolman disease. Infants with hepatosplenomegaly and evidence of malnutrition should have a careful neurological examination and x rays of the abdomen to check for calcium deposits in the adrenal glands. If Wolman disease is suspected on the basis of these tests, acid lipase activity can be measured in the laboratory using white blood cells or skin cells. An absence of acid lipase activity confirms the diagnosis. Carrier testing Individuals suspected of being a carrier of Wolman disease can be confirmed by measuring acid lipase activity in their white blood cells. Carriers will typically demonstrate 50% of normal enzyme activity. |