Incontinentia Pigmenti

What is incontinentia pigmenti?

Incontinentia pigmenti is a condition affecting many body systems, particularly the skin. This disorder, which occurs mainly in females, is characterised by blistering and wart-like skin growths in early childhood followed by changes in skin pigmentation. The condition may also affect the teeth, hair, eyes, and central nervous system (the brain and spinal cord).

How common is incontinentia pigmenti?

Incontinentia pigmenti is an uncommon disorder. Between 700 and 1,000 affected individuals have been reported in the scientific literature.

What genes are related to incontinentia pigmenti?

Mutations in the IKBKG gene cause incontinentia pigmenti.

The IKBKG gene provides instructions for making a protein that helps regulate the activity of nuclear factor-kappa-B. Nuclear factor-kappa-B is a protein complex that normally helps protect cells from self-destructing (undergoing apoptosis) in response to certain signals. In about 80 percent of affected individuals, mutations in the IKBKG gene lead to an abnormally small, nonfunctional version of the IKBKG protein. Other people with incontinentia pigmenti have mutations that prevent any IKBKG protein from being produced. Without this protein, nuclear factor-kappa-B is not regulated properly, and cells are more likely to undergo apoptosis. Researchers believe that this abnormal cell death leads to the signs and symptoms of incontinentia pigmenti.

How do people inherit incontinentia pigmenti?

This condition is inherited in an X-linked dominant 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. The inheritance is dominant if one copy of the altered gene in each cell is sufficient to cause the condition. In most cases, males experience more severe symptoms of the disorder than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

Research suggests that incontinentia pigmenti occurs mainly in females because males with mutations in the IKBKG gene usually die before birth. Males with these mutations have no functional IKBKG protein in any of their cells. In females with incontinentia pigmenti, some cells produce normal protein from the IKBKG gene and other cells produce no functional IKBKG protein. The resulting overall reduction in the amount of functional IKBKG protein leads to the signs and symptoms of incontinentia pigmenti.

What other names do people use for incontinentia pigmenti?

• Bloch-Siemens-Sulzberger Syndrome
• Bloch-Siemens syndrome
• Bloch-Sulzberger Syndrome
• IP