Mucopolysaccharidosis Type IVA

Mucopolysaccharidosis Type IVA (MPS IVA) is an inherited metabolic disorder caused by a deficiency of an enzyme called N-acetylgalactosamine-6-sulfatase (GALNS) that affects lysosomal function. It is characterized by the accumulation of the excess of glycosaminoglycans. This leads to physical, mental and behavioral symptoms.

MPS IVA is caused by a mutation in the GALNS gene, which can be inherited in an autosomal recessive manner. Symptoms may include joint stiffness, aortic valve disease, narrowing of the aorta, and progressive skeletal abnormalities involving bones and joints. In addition, people with MPS IVA may have hearing loss, an enlarged liver and/or spleen, heart valve disease, neurological problems such as seizures, hernias, and clouding of the cornea. Symptoms generally begin within the first few years of life.

Symptoms of Mucopolysaccharidosis Type IVA

Joint stiffness
Aortic valve disease
Narrowing of the aorta
Progressive skeletal abnormalities
Hearing loss
An enlarged liver and/or spleen
Heart valve disease
Neurological problems such as seizures
Hernias
Clouding of the cornea

Diagnosis of Mucopolysaccharidosis Type IVA

Diagnosis of MPS IVA is based on a combination of the medical history, physical examination, biochemical and molecular testing. A combination of laboratory tests are used to diagnose MPS IVA including enzyme assay of GALNS activity, urine analysis for GAGs, genetic testing for GALNS mutations, and imaging tests such as X-rays and MRI scans.

Treatment for Mucopolysaccharidosis Type IVA

The treatment for MPS IVA is supportive and aimed at managing the symptoms. Symptomatic treatment may include physiotherapy and use of braces or casts to treat joint stiffness and skeletal abnormalities. In some cases, surgical intervention is required. Recently, a potentially curative bone marrow transplant has been used to treat some people with MPS IVA.