ASAH1

The ASAH1 gene provides instructions for making an enzyme called acid ceramidase. This enzyme is found in the lysosomes (compartments that digest and recycle materials in the cell), where it breaks down fats called ceramides into other fats that can be used by the body. Ceramides make up one subtype of a group of fats called sphingolipids.

Ceramides are also thought to play a role in the growth and death of cells, but this function likely takes place outside of the lysosome.

Farber lipogranulomatosis - caused by mutations in the ASAH1 gene

More than 15 mutations in the ASAH1 gene have been found to cause Farber lipogranulomatosis. Most of these mutations are caused by a change in a single protein building block (amino acid) in acid ceramidase, which prevents the enzyme from functioning normally.

A lack of functional acid ceramidase or a severe reduction in the enzyme's activity results in an accumulation of ceramides in the cells and tissues of the lung, liver, colon, muscles used for movement (skeletal muscles), cartilage, and bone. This buildup causes the signs and symptoms of Farber lipogranulomatosis, and the severity of the disease depends on the amount of ceramide accumulation.