Menkes syndrome

Menkes syndrome is a disorder that affects copper levels in the body. It is characterized by sparse and coarse hair, growth failure, and deterioration of the nervous system. Additional signs and symptoms include weak muscle tone (hypotonia), sagging facial features, seizures, mental retardation, and developmental delay. Onset of Menkes syndrome typically begins during infancy. In rare cases, symptoms begin later in childhood.

Occipital horn syndrome (sometimes called X-linked cutis laxa), is a less severe form of Menkes syndrome that begins in early to middle childhood. It is characterized by wedge-shaped calcium deposits in a bone at the base of the skull (the occipital bone), coarse hair, and loose skin and joints.

The incidence of Menkes syndrome and occipital horn syndrome is estimated to be 1 in 100,000 individuals.

Mutations in the ATP7A gene cause Menkes syndrome.

A mutation in the ATP7A gene results in poor distribution of copper to the body's cells. Copper accumulates in some tissues, such as the small intestine and kidneys, while the brain and other tissues have unusually low levels. The decreased supply of copper can reduce the activity of numerous copper-containing enzymes that are necessary for the structure and function of bone, skin, hair, blood vessels, and the nervous system.

Read more about the ATP7A gene.

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 striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

About one-third of Menkes cases result from new mutations in the gene and occur in people with no history of the disorder in their family.