The MANBA gene provides instructions for making the enzyme beta-mannosidase. This enzyme works in the lysosomes, which are compartments that digest and recycle materials in the cell. Within lysosomes, the enzyme helps break down complexes of sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins). Beta-mannosidase is involved in the last step of this process, helping to break down complexes of two sugar molecules (disaccharides) containing a sugar molecule called mannose.
Approximately 12 mutations that cause beta-mannosidosis have been identified in the MANBA gene. The mutations result in a beta-mannosidase enzyme with little or no activity, and interfere with the ability of the enzyme to perform its role in breaking down mannose-containing disaccharides. These disaccharides gradually accumulate in the lysosomes and cause cells to malfunction, resulting in the signs and symptoms of beta-mannosidosis.
- mannosidase, beta A, lysosomal