Hypomelanosis of Ito

Alternate names

Ito hypomelanosis; ITO; Incontinentia pigmenti achromians; IPA; Incontinentia pigmenti type 1 (formerly)

Definition

Hypomelanosis of Ito, also called incontinentia pigmenti achromians, causes streaked, whirled, or mottled patches of light-colored skin.

Epidemiology

It has been estimated that between 1 in 8,000 -10,000 people may have hypomelanosis of Ito. Females are more likely to have it than males. The exact number of people with this condition is unknown.

Cause

• In many cases the cause of hypomelanosis of Ito can not be determined.
• Some cases have been associated with an underlying chromosomal abnormality.
• The skin patterning may reflect “mosaicism.”
• In mosaicism the person has some cells with normal chromsomes, and some with the chromosomal or gene abnormality.
• Mosaicism often leads to 2 cell types, leading to both areas of hypopigmented (light areas of skin) and hyperpigmented skin (darker areas of skin).
• X-chromosome alterations are also found in hypomelanosis of Ito, and recent studies show that X-chromosome inactivation, activation, and mosaicism as the main causes of these differences in the skin.
• In less than 3% of the patients there is a family history of hypomelanosis of Ito–type skin lesions.
• Although hypomelanosis of Ito syndrome is most commonly a de novo occurrence (without any other cases in the family), rare cases appear to be transmitted as an autosomal dominant trait.
• About 10% of the patients report a family history of seizures or epilepsy.

Inheritance

• Usually hypomelanosis of Ito is sporadic.
• “Sporadic” denotes either a genetic disorder that occurs for the first time in a family due to a new mutation or the chance occurrence of a non-genetic disorder or abnormality that is not likely to recur in a family.
• In less than 3% of the patients there is a family history of hypomelanosis of Ito–type skin lesions.
• Fmilial cases appear to be transmitted as an autosomal dominant trait.
• About 10% of the patients report a family history of seizures or epilepsy.
• Cases of autosomal recessive, and X-linked inheritance has also been reported in the literature.

Signs and symptoms

• It causes streaked, whirled, or mottled patches of light-colored skin.
• These skin changes often develop within the first two years of life.
• Other symptoms may include varying degrees of learning disability, seizures, increased body hair, scoliosis, and strabismus.
• Neurological problems are found in 76% of patients during the first decade of life.
• Intellectual disability and seizures are the most common presenting symptoms.
• In one study, about 50% of the patients presented with seizures, although a lower frequency (37%) was reported in the pediatric dermatology clinic–based series.
• Generalized tonic-clonic seizures were most common (25%), whereas partial seizures were noted in 12% of patients, infantile spasms were reported in 8%, and myoclonic seizures were observed in 4%.

Diagnosis

• Hypomelanosis of Ito is diagnosed based on the symptoms and a clinical examination.
• A careful evaluation with a Wood's lamp may help confirm the diagnosis.
• Additional genetic testing through a skin biopsy can look for chromosomal mosaicism.

Treatment

Treatment for hypomelanosis of Ito is focused on managing the symptoms. Therapies are aimed at treating the symptoms such as seizures, scoliosis, and strabismus. Children with this condition often receive their care from a multidisciplinary team of healthcare providers, including a pediatric ophthalmologist, neurologist, orthopedic specialist and others as needed.

NIH genetic and rare disease info

• NIH info on Hypomelanosis of Ito

Hypomelanosis of Ito is a rare disease.

Hypomelanosis of Ito Resources
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