Hypomelanosis of Ito, also known as incontinentia pigmenti achromians, is the third most frequent phakomatosis, involving a wide spectrum of defects in multiple organ systems.
The prevalence is unknown, being reported as between 1 per 8000 patients in a general pediatric hospital 3 and 1 per 600–700 patients referred to a pediatric neurology service 1.
As a neurocutaneous disease, the skin lesions are remarkable and are present in the first year of life in ~70% of patients. Lesions manifest as hypopigmented zones or spots with irregular borders, sometimes whorls, or linear white streak lines following Blaschko’s lines. Other cutaneous-associated manifestations include café-au-lait spots, cutis marmorata telangiectatica congenita (CMTC), angiomatous nevi, Mongolian blue spot, and nevus of Ota. Iris hypopigmentation is also reported. It is important to note that the disease severity is not correlated with the extent of cutaneous lesions 1.
Changes in hair color, diffuse alopecia and hair with trichorrhexis nodosa are reported as scalp manifestations of this disease.
- intellectual disability and epilepsy: seizures commonly appear early and generally are refractory to anticonvulsant drugs
- a variety of non-specific ocular alterations
- dental: defective dental implantation, conical teeth, partial anodontia, and hypodontia
- musculoskeletal disorders, such as hypotonia
- occasional association with benign tumors, including
The exact cause of hypomelanosis of Ito is unknown with many cases being associated with genetic mosaicism and sporadic gene mutations.
The hypopigmented lesions are the result of a decrease in the number of melanocytes and in the number and size of melanosomes 1.
CT and, more clearly, MRI can demonstrate several abnormalities.
- cerebellar atrophy or hypoplasia
- focal or generalized cerebral atrophy
- neuronal heterotopias
Head and neck
- cleft lip and palate
- bifid uvula
- nose and ear anomalies
- hypodontia (small teeth)
- partial anodontia (lack of teeth)
- impacted dentition
Treatment and prognosis
There is no specific treatment; treatment is based on symptomatology.
History and etymology
Was described by Minor Ito (1884-1982), Japanese dermatologist, in 1952 2.
The most commonly confused diagnosis is with incontinentia pigmenti, a rarer phakomatosis.
- 1. Pascual-Castroviejo I, Roche C, Martinez-Bermejo A et-al. Hypomelanosis of ITO. A study of 76 infantile cases. Brain Dev. 1998;20 (1): 36-43. Pubmed citation
- 2. Ito M. Studies on melanin. Tohoku J. Exp. Med. 2004;55 (Suppl. 1): 1-104. Pubmed citation
- 3. Zvulunov A, Esterly NB. Neurocutaneous syndromes associated with pigmentary skin lesions. J. Am. Acad. Dermatol. 1995;32 (6): 915-35. Pubmed citation
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