Coffin-Lowry syndrome is caused by mutations in the RPS6KA3 gene, which is located on the X chromosome.
Understanding the Cause
- Gene Involved: The primary culprit is the RPS6KA3 gene.
- X-Linked Inheritance: Because the RPS6KA3 gene is located on the X chromosome, Coffin-Lowry syndrome typically affects males more severely than females. Males have only one X chromosome, so a single mutated copy of the gene is enough to cause the syndrome. Females have two X chromosomes, and if one copy of the gene is normal, it can often compensate for the mutated copy.
- RPS6KA3 Function: The RPS6KA3 gene provides instructions for making a protein called ribosomal protein S6 kinase alpha-3. This protein is involved in cell signaling pathways that are important for learning, memory, and bone growth.
- Mutation Impact: Mutations in the RPS6KA3 gene disrupt the normal function of this protein, leading to the characteristic features of Coffin-Lowry syndrome.
Inheritance Patterns
- Males: Affected males inherit the mutated RPS6KA3 gene from their mother.
- Females: Females can be carriers if they inherit one copy of the mutated gene and one normal copy. Carriers may experience milder symptoms or none at all. A female can also be affected if she inherits two copies of the mutated gene, or if the normal copy of the RPS6KA3 gene is inactivated (X-inactivation).
Summary
In conclusion, Coffin-Lowry syndrome arises from mutations within the RPS6KA3 gene, which affects a protein crucial for cell signaling, learning, memory, and bone development. This X-linked inheritance pattern results in differing severities between males and females.
