Incontinentia pigmenti (IP) (MIM 308310) is a disorder of the skin, eye and central nervous system that occurs primarily in females but occasionally in males. Incontinentia pigmenti is an X-linked condition with early lethality in males (X-linked dominant). Affected females typically have an erythematous, vesicular rash that appears at birth or soon after birth. This rash evolves over time, becoming verrucous and pigmented, and then atrophic. Adults have areas of linear hypopigmentation. Other manifestations include alopecia, hypodontia/misshapen teeth, leukocytosis with eosinophilia, vascular abnormalities of the retina, and other eye findings. Skeletal and dental anomalies are common and quite varied. Neurologic manifestations are primarily seizures and mental retardation.
Clinical recognition of IP began during the first decade of the twentieth century. Garrod briefly described a young girl with severe neurodevelopmental deficits who had peculiar skin pigmentation consisting of linear streaks and whorls of hyperpigmentation (Garrod, 1906). A more detailed description of IP was provided by Sulzberger in 1928, who noted the association of the skin pattern with other organ involvement in a patient reported 2 years earlier by Bloch, who introduced the term incontinentia pigmenti.
Clinical features (Table 13.1)
The skin lesions are the hallmark of IP, and they typically manifest in stages which evolve over weeks to years. The clinical variability in these skin lesions has been underemphasized. The onset and duration of each stage vary among patients; not all patients experience all four stages.