Hypomelanosis of Ito (incontinentia pigmenti achromians) is not a distinct entity, but rather a manifestation of many different states of somatic mosaicism displaying in the skin with "whorls" of hypopigmented skin patches. Skin lesions usually develop in early infancy and remain unchanged through childhood and beyond.

Neurological findings can be observed in patients with hypomelanosis of Ito including treatment-resistant seizures that develop in infancy, psychomotor developmental delays, and some cases of severe neurologic impairment with hemimegalencephaly. Ocular abnormalities are common and include strabismus, aplasia / hypoplasia of the iris, and heterochromia iridis. Other less common associated findings include cleft lip and palate, anodontia, alopecia, scoliosis, and limb length discrepancy.