Incontinentia pigmenti (IP) is an inherited disorder of skin pigmentation that is also associated with abnormalities of the teeth, skeletal system, eyes, and central nervous system. It is one of a group of gene-linked diseases known as neurocutaneous disorders.
In most cases, IP is caused by mutations in a gene called NEMO (NF-kappaB essential modulator). Males are more severely affected than females. Most newborns with IP will develop discolored skin within the first two weeks.
Discolored skin is caused by excessive deposits of melanin (normal skin pigment). The pigmentation involves the trunk and extremities, is slate-grey, blue or brown, and is distributed in irregular marbled or wavy lines. The discoloration fades with age. Although the skin abnormalities usually regress, and sometimes disappear completely, there may be residual neurological difficulties.
Neurological problems include:
- Loss of brain tissue (known as cerebral atrophy)
- The formation of small cavities in the central white matter of the brain
- Loss of neurons in the cerebellar cortex
About 20% of children with IP will have:
- Slow motor development
- Muscle weakness in one or both sides of the body
- Mental retardation
- Visual problems, including crossed eyes, cataracts, and severe visual loss
- Missing or peg-shaped teeth
A related disorder, incontinentia pigmenti achromians, features skin patterns of light, unpigmented swirls and streaks that are the reverse of IP. Associated neurological problems are similar.
The skin abnormalities of IP usually disappear by adolescence or adulthood without treatment. Diminished vision may be treated with corrective lenses, medication, or, in severe cases, surgery. A specialist may treat dental problems. Neurological symptoms such as seizures, muscle spasms, or mild paralysis may be controlled with medication and/or medical devices and with the advice of a neurologist.