The disorder is characterized by unilateral or
bilateral macular hypopigmented whorls, streaks, and patches that exist from
birth. The lines of Blaschko are defined by a pattern determined by
different nevoid on the human skin and mucosae. The cause is unknown, and
their distributions do not follow nerves, vessels, or lymphatics. In 1901,
Blaschko pointed out that the lines described by these conditions not only
did not correspond to any known anatomical basis but were remarkably
consistent both from patient to patient and even from one disease to
another. Neurologic impairment (70% of cases) can be severe and present
as mental retardation, seizures, neurologic syndromes, cerebellar signs, and
hearing loss. Abnormalities of the eyes (strabismus, retinal changes, optic
nerve hypoplasia) and the musculoskeletal system (scoliosis, syndactyly)
occur in some patients. Other reported abnormalities include cleft palate,
hair, nail, teeth, limb, hand and/or foot abnormalities, hemihypertrophy,
hypotonia, and face and/or skull anomalies.