acid sphingomyelinase deficiency

Acid sphingomyelinase deficiency is a rare lysosomal disorder that affects how the body processes fats. This condition occurs due to issues with an enzyme caused by changes in both copies of a gene. The disorder is known to present along a continuum of severity. At one end, individuals may have a severe form (historically called Niemann-Pick disease type A) where they experience enlarged liver and spleen and rapidly declining neurological functions that can lead to early childhood death. At the other end, a milder form (historically called Niemann-Pick disease type B) leads to chronic issues with the liver, spleen, and lungs, allowing survival into adulthood.

People with this condition may experience a range of symptoms depending on the severity of the disease. In the severe form, symptoms include an enlarged liver and spleen and rapid neurological decline. In the milder forms, persistent issues with the liver and spleen, along with breathing difficulties due to lung involvement, are commonly reported.

The condition is caused by autosomal recessive changes in a gene that leads to a reduction or loss of function of the enzyme acid sphingomyelinase. These genetic changes affect the body's ability to break down certain fats, which then accumulate in cells and lead to various symptoms. This genetic issue is present when both copies of the gene have changes.

Information about treatment is currently limited for this condition.

The outlook for individuals with acid sphingomyelinase deficiency varies. Those with the severe form of the condition may experience rapid neurological decline and may not survive beyond early childhood. In contrast, individuals with the milder form often live into adulthood, although they may face ongoing challenges with organ function and other symptoms.

Information about research is currently limited for this condition.