Incontinentia Pigmenti

Background and History: 

This primary disorder of the skin was described by two dermatologists in the early part of the 20th century.  The gene mutation causes abnormalities in other areas such as skin, skeleton, brain and the eyes as well.

Clinical Correlations: 

Incontinentia pigmenti is usually evident at birth because of the presence of eruptions such as a rash and blisters in the skin.  Later, small wart-like growths appear in these areas and these processes eventually cause pigmentary changes in the skin, often in a ‘marbled’ pattern seen in young adults.  Hair and dental growth is defective and the nails may be irregular.  The eyes have changes in the iris (colored part of the eye) and the retina may exhibit scarring with abnormal blood vessels and sometimes a retinal detachment.  Cataracts and crossing of the eyes are common.  Vision varies widely depending upon the severity of the eye damage and blindness may be the result in some eyes.  A minority of patients have some degree of mental and movement problems.

Genetics: 

This disorder is caused by a mutation in a gene on the X-chromosome that is generally lethal in males.  Hence, the vast majority of affected individuals are female.  Since only one X-chromosome carries this mutation, half of the male offspring of an affected female will be normal and since the other half who receive the mutant X-chromosome do not survive, usually none of her living male offspring will inherit the disorder.

Diagnosis and Prognosis: 

The diagnosis is often made by dermatologists but neurologists, orthopedists, dentists, and ophthalmologists may also be involved.  There is no treatment for the mutation but associated features may be treatable.

Additional Information
Inheritance/Pedigree: 
X-linked dominant, mother affected