Question: How many people are affected by X-linked intellectual disability, Siderius type ?
Answer: While X-linked intellectual disability of all types and causes is relatively common, with a prevalence of 1 in 600 to 1,000 males, the prevalence of the Siderius type is unknown. Only a few affected families have been described in the scientific literature.
Source: GHR

Question: Is X-linked intellectual disability, Siderius type inherited ?
Answer: This condition is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
Source: GHR