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Diseases

Genetic and Rare Diseases Information Center (GARD)

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Incontinentia pigmenti


Other Names for this Disease

  • Bloch-Sulzberger syndrome
  • Incontinentia pigmenti type 2 (formerly)
  • Incontinentia pigmenti, familial male-lethal type
  • IP
  • IP2 (formerly)
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Inheritance

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How is incontinentia pigmenti inherited?

Incontinentia pigmenti (IP) is inherited in an X-linked dominant pattern. The gene responsible for causing IP (IKBKG) is on the X chromosome (one of the two sex chromosomes) which is why the condition is "X-linked." The condition is dominant because In females (who have two X chromosomes), a mutation in only one of the two copies of the gene is enough to cause the condition.[1]

In males, who have only one X chromosome, most IKBKG mutations result in a total loss of the protein the gene encodes. Males don't have another X chromosome with a working copy of the gene. When there is no working copy of this gene, IP is lethal in early development. This is why so few males are born with IP. Males living with this condition may have an IKBKG mutation with a mild effect; a mutation in only some of the body's cells (mosaicism); or an extra copy of the X chromosome in each cell.[1]

Some people with IP inherit an IKBKG mutation from a parent with the condition, while other cases are due to new mutations in the gene and occur in people with no history of the condition in their family.[1] When a female with IP has children, each female child has a 50% (1 in 2) risk to inherit the mutated gene. If a male is conceived, there is a 50% risk to be unaffected and a 50% risk to be affected and likely miscarry.
Last updated: 5/13/2014

References
  1. Incontinentia pigmenti. Genetics Home Reference. June, 2008; http://ghr.nlm.nih.gov/condition/incontinentia-pigmenti. Accessed 5/13/2014.


Other Names for this Disease
  • Bloch-Sulzberger syndrome
  • Incontinentia pigmenti type 2 (formerly)
  • Incontinentia pigmenti, familial male-lethal type
  • IP
  • IP2 (formerly)
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.