Nature Genetics pp 10 - 11

A new gene has been identified that may be involved in the pathogenesis of Rett syndrome - a neurological disorder resulting in autism, seizures and loss of speech, almost exclusively in girls before the age of 18 months -- as reported in the January issue of Nature Genetics.

The primary genetic cause of Rett syndrome is a mutation in the gene MECP2, encoding a protein thought generally to affect the expression of many other genes, several of which probably contribute to the disease. The search for MECP2 'target' genes that are relevant to the development of Rett syndrome has been difficult, but Terumi Kohwi-Shigematsu and colleagues have now identified the gene DLX5 as a strong candidate. The authors found that DLX5 expression was altered in the brains of mice lacking MECP2. In humans, DLX5 is an 'imprinted' gene, and is expressed only from the copy received from one's mother. In cells from individuals with Rett syndrome, however, they found that the gene was expressed from both copies, resulting in an overproduction of the protein.

DLX5 regulates the production of enzymes that synthesize gamma-aminobutyric acid (GABA), a neurotransmitter that has been linked to the development of other neurological disorders, suggesting that this pathway may have role in at least some of the features of Rett syndrome.