Adducted thumbs with mental retardation (ATR-X) is a rare genetic disorder that affects mainly males. It is caused by mutations in the ATRX gene, which provides instructions for making a protein involved in regulating the expression of other genes.
The main features of ATR-X include intellectual disability, characteristic facial features, and abnormal positioning of the thumbs. The affected individuals typically have delayed development and exhibit behaviors such as aggression, hyperactivity, and self-injurious behavior.
Other common features of ATR-X include weak muscle tone, seizures, genital abnormalities, and skeletal abnormalities. The severity of symptoms can vary widely, even among members of the same family with the disorder.
ATR-X is inherited in an X-linked pattern, which means that the mutated gene is located on the X chromosome. Females typically have two X chromosomes, so if one X chromosome contains the mutated gene, the other X chromosome can often compensate for it. Males, however, have only one X chromosome, so if the gene is mutated, they will develop the disorder.
There is no cure for ATR-X, and treatment is based on the individual’s specific symptoms. Management may include physical, occupational, and speech therapy, as well as medications to control seizures, aggressive behavior, and other symptoms.