Which are the causes of Morquio Syndrome?

Morquio Syndrome:

Morquio Syndrome, also known as mucopolysaccharidosis type IV (MPS IV), is a rare genetic disorder that affects the metabolism of certain complex molecules called glycosaminoglycans (GAGs). This condition is characterized by the deficiency or absence of specific enzymes required to break down GAGs, leading to their accumulation in various tissues and organs of the body.

Causes of Morquio Syndrome:

Morquio Syndrome is an autosomal recessive disorder, meaning that both parents must carry a mutated gene to pass it on to their child. The condition is caused by mutations in one of two genes: GALNS (N-acetylgalactosamine-6-sulfatase) or GLB1 (beta-galactosidase). These genes provide instructions for producing enzymes that are essential for the breakdown of GAGs.

Enzyme Deficiency:

In individuals with Morquio Syndrome, there is a deficiency or absence of either GALNS or GLB1 enzyme. This deficiency impairs the breakdown of GAGs, specifically keratan sulfate and chondroitin sulfate, which are important components of connective tissues, cartilage, and other structures in the body.

Accumulation of GAGs:

Due to the enzyme deficiency, GAGs accumulate in various tissues and organs, leading to progressive damage and dysfunction. The accumulation primarily affects the skeletal system, heart, respiratory system, eyes, and other organs.

Genetic Mutations:

The specific mutations in the GALNS or GLB1 genes determine the severity and clinical presentation of Morquio Syndrome. These mutations can vary greatly, resulting in a spectrum of symptoms and disease progression.

Autosomal Recessive Inheritance:

To inherit Morquio Syndrome, an individual must receive two copies of the mutated gene, one from each parent. If both parents are carriers of the mutated gene, there is a 25% chance with each pregnancy that their child will have Morquio Syndrome.

Carrier Status:

Carriers of Morquio Syndrome typically do not exhibit any symptoms of the condition. However, they have a single copy of the mutated gene and can pass it on to their children. If both parents are carriers, there is a 50% chance with each pregnancy that their child will be a carrier.

Prevalence:

Morquio Syndrome is a rare disorder, with an estimated incidence of 1 in 200,000 to 300,000 live births. The condition affects both males and females of all ethnic backgrounds.

Conclusion:

Morquio Syndrome is caused by mutations in the GALNS or GLB1 genes, leading to a deficiency or absence of specific enzymes required for the breakdown of GAGs. This results in the accumulation of GAGs in various tissues and organs, causing progressive damage and dysfunction. The condition is inherited in an autosomal recessive manner, requiring both parents to be carriers of the mutated gene. Morquio Syndrome is a rare disorder with a wide spectrum of symptoms and disease severity.