The most distinctive finding associated with hypomelanosis of Ito is characteristic skin changes. Most affected individuals develop areas that lack skin color (hypopigmentation). Any area of the body may be involved although the scalp, palms and soles are rarely affected. Skin changes may occur as patches, streaks or spiral-shaped (whorled) areas of discoloration and may affect one side of the body (unilateral) or both sides (bilateral). Affected areas of skin are usually normal otherwise. The skin Lesions usually appear during the first year of life and remain unchanged through childhood, but may fade or darken in adulthood. Skin Lesions are not associated with Inflammation or a premalignant (verrucous) condition.
In some cases of hypomelanosis of Ito, additional non-cutaneous features may occur. It is important to note that the specific symptoms that occur vary greatly from person to person and affected children will not have all the symptoms discussed below. Because children with the characteristic skin changes of hypomelanosis of Ito and no associated abnormalities may go unreported, determining the actually frequency of associated findings is difficult. The number of affected individuals with additional symptoms has been estimated to be anywhere from 30-90 percent.
Neurological findings may occur in some cases including Seizures that occur during infancy and are often resistant to therapy, some degree of cognitive impairment, and delays in attaining milestones that require the coordination of muscular and mental activity (psychomotor impairment). In some cases, one side of the brain may be larger than the other (hemimegalencephaly).
Less often, some individuals have crossed eyes (strabismus), eyes that a spaced apart wider than normal (hypertelorism), cleft palate, cleft lip, and dental anomalies such as missing teeth (anodontia). Loss of hair usually in a patchy pattern (alopecia) may also occur. Some infants may have microcephaly, a condition that indicates that the head circumference is smaller than would be expected for age and sex; others may have macrocephaly, which indicates that head circumference is larger than would normally be expected.
A variety of Skeletal abnormalities have occurred in individuals with hypomelanosis of Ito including abnormal side-to-side curvature of the spine (scoliosis), disproportionate length of the legs (limb length discrepancy), and abnormal fixation or “locking” of the pinky in a bent position (clinodactyly). Diminished muscle tone (hypotonia) may also occur.
Additional symptoms that may affect individuals with hypomelanosis of Ito include additional eye abnormalities, deafness, overgrowth of one side of the body (hemihypertrophy), heart (cardiac) abnormalities, kidney (renal) malformations, and abnormalities of the genitourinary tract, which contains the reproductive organs and urinary system.