Hypomelanosis of Ito. Neurological Complications in 34 Cases

Abstract

ABSTRACT:We studied 34 Spanish children with hypomelanosis of Ito. This disease has an incidence of 1 per 1000 new patients consulting a paediatric neurological service, or 1 per 8000-10,000 unselected patients in a children's hospital. About 94% of our patients show noncutaneous abnormalities. Mental retardation (IQ below 70) was present in 64.7%; another 14.7% had an IQ between 70 and 90, usually associated with poor school performance. Four children exhibited autistic behaviour. Seizures of various types were present in 53% of cases. Other skin alterations in addition to the typical hypomelanosis were observed in 38% of our cases: caf6-au-lait spots, angiomatous nevi, nevus marmorata, nevus of Ota, Mongolian blue spot, heterochromia of the iris or hair, and other nonspecific pigmentations. Other associated disorders occur inconsistently and include macrocephaly, microcephaly, h6mihypertrophy, kyphoscoliosis, coarse facial features, genital anomalies, inguinal hernia, congenital heart disease, hypertelorism, and abnormalities of the teeth, feet and eyes. Autosomal dominant inheritance is demonstrated in some but not all cases.

Don’t it make my blue eyes brown: heterochromia and other abnormalities of the iris

“…16 Binocular heterochromia may arise as an isolated congenital anomaly or as an autosomal dominant trait. 16 Heterochromia iridum has also been reported in association with Sturge-Weber syndrome, 19 hypomelanosis of Ito, 20 and linear scleroderma. 21 Recently, Quinlan and Shwayder 22 reported a case of a large facial café au lait macule in association with heterochromia iridum.…”

Hypomelanosis of Ito: No entity, but a cutaneous sign of mosaicism

“…RuizMaldonado et al [1992] reported a frequency of 1 in every 7,805 general pediatric outpatients, 1 in every 790 general pediatric dermatology outpatients, 1 in every 2,983 general pediatric inpatients, and 1 in every 63 pediatric dermatology inpatients. A frequency of 1 in every 8,000 to 10,000 patients of a general pediatric hospital and 1 in every 1,000 patients in a pediatric neurology service had been determined in Spain [Pascual-Castroviejo et al, 1988].…”

Ocular Symptomatology in Familial Hypomelanosis Ito

“…In the changes that occur far more frequently than in the normal popula tion, such as strabismus [5,8,9,11,[13][14][15], and palpebral anomalies [8,9,11,[13][14][15][16], an in terrelationship with HI seems likely. Also in those ocular anomalies that are characterized by impaired pigmentation, such as iris dyspigmentations [5,8,9,13,17] and tapetoretinal dyspigmentations [14], already described as tesselated and 'salt and pepper' fundus [8,9,11,13], a connection seems feasible. This is all the more likely, because the mother had lid anomalies with subsequent strabismus and mother and daughter had iris dyspigmenta tions in a similar pattern as well as tapetoreti nal dyspigmentations.…”

“…Although both patients had a tortuositas vasorum, no HI relatedness can be verified. In ta ble 1, ocular changes in both mother and daughter have been compared with all previ ously described changes [6,12,[17][18][19]. Changes other than those found in the eyes have all been described before.…”

“…So far there is no proof that HI is hereditary in an autosomal dominant mode [11,12,17,18]. However, it is sure that it is no X-chromosomal mode, since HI may be contracted by both sexes and the disease may also be transmitted from the father to the son [5], For this reason it is likely to be an autosomal dominant genetic trait with variable penetration and expressivity [5], implying that there is a clear genetic dis tinction between HI and incontinentia pigmenti Bloch-Sulzberger (X-chromosomal mode) [24] despite some existing similarities [25,26].…”