X-linked creatine deficiency is an inherited disorder that primarily affects the brain. People with this disorder have intellectual disability, which can range from mild to severe, and delayed speech development. Some affected individuals develop behavioral disorders such as attention-deficit/hyperactivity disorder (ADHD) or autistic behaviors that affect communication and social interaction. They may also experience seizures. Children with X-linked creatine deficiency may grow slower and develop motor skills, such as sitting and walking, later than their peers. Affected individuals tend to tire easily.

Variants (also known as mutations) in the SLC6A8 gene cause X-linked creatine deficiency. The SLC6A8 gene provides instructions for making a protein that transports a compound called creatine into cells. Creatine is needed for the body to store and use energy properly.

The prevalence of X-linked creatine deficiency is unknown. More than 150 affected individuals have been identified. The disorder has been estimated to account for between 1 and 2 percent of males with intellectual disability.

This condition is inherited in an X-linked pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a variant in one of the two copies of the gene in each cell may or may not cause the disorder. In males (who have only one X chromosome), a variant in the only copy of the gene in each cell causes the disorder. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

Published Date: February 06, 2023
Published By: National Institutes of Health