Diagnosis
The diagnosis of IP is established by clinical findings and occasionally by corroborative skin biopsy. Molecular genetic testing of the NEMO IKBKG gene (chromosomal locus Xq28) reveals disease-causing mutations in about 80% of probands. Such testing is available clinically.
In addition, females with IP have skewed X-chromosome inactivation; testing for this can be used to support the diagnosis.
Many people in the past were misdiagnosed with a second type of IP, called IP2. This has now been given its own name - 'Hypomelanosis of Ito' (incontinentia pigmenti achromians). This has a slightly different presentation: swirls or streaks of hypopigmentation and depigmentation. It is NOT inherited. It does not inolve skin stages 1 or 2. 33-50% of patients have multisystem involvement — eye, skeletal, and neurological abnormalities. Its chromosomal locus is at Xp11, not Xp28.
Read more about this topic: Incontinentia Pigmenti