[4] Alpha-mannosidosis is an inherited lysosomal storage disease that causes hearing loss, intellectual disability, facial and skeletal abnormalities, and immunological deficiencies.

Autosomal recessive mutations in the MAN2B1 gene, which is situated on chromosome 19 (19 p13.2-q12), are the cause of alpha-mannosidosis.

Acid alpha-mannosidase activity within leukocytes or other nucleated cells is used to make the diagnosis, which can then be verified by genetic testing.

[5] Beta-mannosidosis is an extremely rare metabolic storage disease caused by a deficiency of the enzyme beta-mannosidase, which is involved in the breakdown of glycoproteins.

The clinical manifestation can range from mild to severe and includes symptoms like hearing loss, mental retardation, hyperactivity, behavioral issues, and recurrent respiratory and skin infections.