Incontinentia pigmenti (IP) is a rare neurocutaneous disorder with a frequency 
of 1 in 50,000 newborn, and is associated with mutations in IKBKG gene (NEMO) in 
Xq28, inherited as an X-linked dominant trait. Clinical manifestations detected 
since the newborn period are highly variable, with 3 well established sequential 
or overlapped states and each with a characteristic differential diagnosis. With 
PCR+RFLPs, we analyzed the IKBKG gene in 4 patients with different clinical 
manifestations and characteristic skin biopsy. In all 4 patients the same 
deletion of exons 4 to 10 was identified. In female patients in whom the 
dermatological lesions lead to the suspicion of an IP diagnosis, it is important 
to have the complete, multidisciplinary and molecular analysis of their first 
level female relatives. This should give us a clear diagnosis, which is the 
first step to complete genetic counselling.