The molecular genetics of incontinentia pigmenti.

Incontinentia pigmenti (IP) is an unusual and fascinating disorder of the developing neuroectoderm. IP is an X-linked dominant disease characterized by congenital and age-related dermatologic abnormalities and significant neurological, ophthalmologic, and dental anomalies. Two distinct IP gene loci, IP1, mapped to Xp11.21, and IP2, mapped to Xq28, have been identified. The necessary prerequisites for cloning the IP1 gene by a positional cloning approach are available. Ten DNA markers have been mapped to a region between IP1 X-chromosomal translocation breakpoints within region Xp11.21. Approximately 60% of the 2,500-kb region between IP1 X-chromosomal translocation breakpoints has been cloned in yeast artificial chromosome clones.