Question: What is (are) Allan-Herndon-Dudley syndrome ?
Answer: Allan-Herndon-Dudley syndrome is a rare disorder of brain development that causes moderate to severe intellectual disability and problems with movement. This condition, which occurs exclusively in males, disrupts development from before birth. Although affected males have impaired speech and a limited ability to communicate, they seem to enjoy interaction with other people. Most children with Allan-Herndon-Dudley syndrome have weak muscle tone (hypotonia) and underdevelopment of many muscles (muscle hypoplasia). As they get older, they usually develop joint deformities called contractures, which restrict the movement of certain joints. Abnormal muscle stiffness (spasticity), muscle weakness, and involuntary movements of the arms and legs also limit mobility. As a result, many people with Allan-Herndon-Dudley syndrome are unable to walk independently and become wheelchair-bound by adulthood.
Source: GHR

Question: How many people are affected by Allan-Herndon-Dudley syndrome ?
Answer: Allan-Herndon-Dudley syndrome appears to be a rare disorder. About 25 families with individuals affected by this condition have been reported worldwide.
Source: GHR

Question: Is Allan-Herndon-Dudley syndrome inherited ?
Answer: This condition is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, 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 must be present in both copies of the gene to cause the disorder. 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. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. She can pass on the mutated gene, but usually does not experience signs and symptoms of the disorder. Carriers of SLC16A2 mutations have normal intelligence and do not experience problems with movement. Some carriers have been diagnosed with thyroid disease, a condition which is relatively common in the general population. It is unclear whether thyroid disease is related to SLC16A2 gene mutations in these cases.
Source: GHR

Question: What are the treatments for Allan-Herndon-Dudley syndrome ?
Answer: These resources address the diagnosis or management of Allan-Herndon-Dudley syndrome: - Gene Review: Gene Review: MCT8-Specific Thyroid Hormone Cell-Membrane Transporter Deficiency - Genetic Testing Registry: Allan-Herndon-Dudley syndrome - MedlinePlus Encyclopedia: Intellectual Disability - MedlinePlus Encyclopedia: T3 Test These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
Source: GHR