How is Coffin Lowry Syndrome (CLS) Inherited?

Coffin-Lowry Syndrome follows an X-linked inheritance pattern. Unlike many other X-linked disorders, CLS is dominant, not recessive.

X-linked inheritance is a pattern located on the X-Chromosome. Females have two X chromosomes, while males have an X and a Y chromosome. This means that when females inherit an X-linked recessive trait, the other X will “cover up” the mutated gene. In X-linked dominant, however, the mutated gene cannot be “covered up,” and is usually still displayed by females.

Since males have only one X chromosome, there is no other X to “cover” the mutation. Therefore, dominant and recessive X-linked traits will always show up in males. One important feature of X-linked diseases is that the father cannot pass it to his son, but can pass it to his daughter.

However, 70-80 percent of affected CLS patients have no family history of the disorder. In these cases, a new mutation has occurred on the X-chromosome by either insertion or deletion of base-pairs.