Rare Infectious Disease News

Disease Profile

Hypomelanosis of Ito

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

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ICD-10

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Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Ito hypomelanosis; ITO; Incontinentia pigmenti achromians;

Categories

Congenital and Genetic Diseases; Eye diseases; Nervous System Diseases;

Summary

Hypomelanosis of Ito, also called incontinentia pigmenti achromians, 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. The exact cause is not known. Many people with hypomelanosis of Ito syndrome have cells that have the normal chromosomes and some cells with abnormal chromosomes. This is known as chromosomal mosaicism. This condition is not inherited in families. Girls tend to be affected more commonly than boys. Diagnosis is based on the symptoms, a clinical examination, and the results of a skin biopsy. Treatment is focused on managing the symptoms.[1][2][3]

Symptoms

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Abnormality of metabolism/homeostasis
Laboratory abnormality
Metabolism abnormality

[ more ]

0001939
Alopecia
Hair loss
0001596
Cataract
Clouding of the lens of the eye
Cloudy lens

[ more ]

0000518
Cerebral atrophy
Degeneration of cerebrum
0002059
Clinodactyly
Permanent curving of the finger
0030084
Coarse facial features
Coarse facial appearance
0000280
Epicanthus
Eye folds
Prominent eye folds

[ more ]

0000286
Gray matter heterotopia
0002282
Hand polydactyly
Extra finger
0001161
Hypertelorism
Wide-set eyes
Widely spaced eyes

[ more ]

0000316
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation

[ more ]

0001249
Iris coloboma
Cat eye
0000612
Irregularly spaced teeth
Irregular dental spacing
Variability of spacing between teeth

[ more ]

0006316
Kyphosis
Hunched back
Round back

[ more ]

0002808
Macrocephaly
Increased size of skull
Large head
Large head circumference

[ more ]

0000256
Macular hypopigmented whorls, streaks, and patches
0005593
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference

[ more ]

0000252
Radial deviation of finger
0009466
Scoliosis
0002650
Seizure
0001250
Somatic mosaicism
0001442
Strabismus
Cross-eyed
Squint
Squint eyes

[ more ]

0000486
Syndactyly
Webbed fingers or toes
0001159
Thick lower lip vermilion
Increased volume of lower lip
Plump lower lip
Prominent lower lip

[ more ]

0000179

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%.[4]

Cause

In many cases the cause of hypomelanosis of Ito can not be determined.[1] Some cases have been associated with an underlying chromosomal abnormality. The skin patterning may reflect “mosaicism.”[2] In mosaicism the person has some cells with normal chromsomes, and some with the chromosomal or gene abnormality. Click here to view an illustration of mosaicism. 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.[5][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.[1][3]

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.[1][2]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Hypomelanosis of Ito. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

References

  1. Incontinentia pigmenti achromians. MedlinePlus. May 15, 2013; https://www.nlm.nih.gov/medlineplus/ency/article/001461.htm. Accessed 9/17/2015.
  2. Vergine G. Ito hypomelanosis. Orphanet. May, 2008; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=435. Accessed 9/17/2015.
  3. Hypomelanosis of Ito. NORD. Updated 2017; https://rarediseases.org/rare-diseases/hypomelanosis-of-ito/.
  4. Janniger CK. Pediatric Hypomelanosis of Ito. Medscape Reference. November 7, 2014; https://emedicine.medscape.com/article/909996-overview. Accessed 9/17/2015.
  5. Ratz JL. Hypomelanosis of Ito. Medscape Reference. August 11, 2014; https://emedicine.medscape.com/article/1068339-overview. Accessed 9/17/2015.

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