Morquio A Syndrome
Description
Morquio A Syndrome, also known as mucopolysaccharidosis type IV A, is a rare genetic disorder that primarily affects bone growth and development. Individuals with Morquio A Syndrome experience skeletal abnormalities, including short stature, a disproportionate body shape, and joint stiffness. While there is no cure for Morquio A Syndrome, early diagnosis and management can help improve quality of life and address potential complications.
Genes Involved
Morquio A Syndrome is caused by mutations in the GALNS gene, which provides instructions for making an enzyme called N-acetylgalactosamine-6-sulfatase. This enzyme is involved in the breakdown of glycosaminoglycans, complex sugar molecules found in cartilage and other connective tissues. When the GALNS gene is mutated, the enzyme is deficient or absent, leading to the buildup of these molecules in the body, causing the characteristic features of Morquio A Syndrome.
Recognizing the Signs and Symptoms
Recognizing the Signs and Symptoms of Morquio A Syndrome can be crucial for timely intervention. Common symptoms include:
- Short stature, with disproportionately short limbs compared to the torso
- A barrel-shaped chest
- A large head with a prominent forehead
- Joint stiffness and pain, particularly in the knees, hips, and wrists
- Neck instability and limited range of motion
- Spinal curvature (kyphosis or scoliosis)
- Hearing loss
- Corneal clouding (affecting vision)
- Enlarged liver and spleen (hepatosplenomegaly)
Causes
Morquio A Syndrome is an inherited genetic disorder. It is caused by a mutation in the GALNS gene, which is located on chromosome 16. These mutations can be passed down from parents to their children, or they can occur spontaneously (de novo).
Inheritance/recurrence risk
Morquio A Syndrome is an autosomal recessive condition. This means that an individual must inherit two copies of the mutated gene, one from each parent, to develop the disorder. If both parents carry the mutated gene, there is a 25% chance that each child will inherit the disorder, a 50% chance they will be a carrier, and a 25% chance they will not inherit the gene.
