Incontinentia pigmenti (IP) is a rare inherited multisystem disorder characterized by a distinctive swirling pattern of the skin; defects of teeth, hair, and nails; and ophthalmic, central nervous system, and musculoskeletal abnormalities. It progresses through several well-defined stages. IP is transmitted as a dominant X-linked trait with variable expressivity, but many--if not most--cases are sporadic. IP has been shown to result from mutations in the NEMO gene that completely abolish expression of NF-kappaB essential modulator