MPS IV A, also known as Morquio A syndrome, is a rare genetic disorder characterized by the deficiency of an enzyme called N-acetylgalactosamine-6-sulfatase (GALNS). This enzyme is responsible for breaking down certain molecules called glycosaminoglycans (GAGs), specifically keratan sulfate and chondroitin-6-sulfate, in the body.
In MPS IV A, the deficient GALNS enzyme cannot properly break down these molecules, leading to their accumulation in various tissues and organs throughout the body. Consequently, this causes progressive damage to bones, cartilage, and other connective tissues, leading to a wide range of physical and skeletal abnormalities.
Symptoms of MPS IV A usually appear during early childhood and can vary significantly in severity from person to person. Common features include short stature, a characteristic facial appearance (including coarse facial features and a protruding lower face), a shortened neck, joint stiffness, and skeletal abnormalities such as scoliosis and genu valgum (knock knees). Organ dysfunction, such as heart valve abnormalities and respiratory problems, can also occur.
MPS IV A is inherited in an autosomal recessive manner, meaning that an affected individual must inherit two copies of the mutated gene (one from each parent) to develop the disorder. Genetic counseling and carrier testing can be useful tools for individuals with a family history of MPS IV A or individuals looking to assess their risk of having an affected child.
Currently, there is no cure for MPS IV A, and treatment primarily focuses on managing symptoms and improving quality of life. This may include physical therapy, surgical interventions, respiratory support, and enzyme replacement therapy, which aims to supplement the deficient GALNS enzyme. Ongoing research and clinical trials are
