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Hypomelanosis of Ito

Also known as: Hypomelanosis, Incontinentia Pigmenti Achromians, Ito syndrome, Pigmentary Mosaicism

Background

The condition was first described by Dr M Ito in 1951. Hypomelanosis of Ito is a group of disorders with the common feature of increased and/or decreased pigmentation in a characteristic formation with swirling patterns around the trunk and line-like patterns down the legs and arms. Skin specialists (dermatologists) call this pattern 'Blaschko's lines'. The typical skin characteristics are usually noticed in the first year of life, with up to 54 per cent of children affected being diagnosed at birth.

Credits

Medical text written October 1999 by Professor Dian Donnai, Consultant Clinical Geneticist, St Mary's Hospital, Manchester, UK. Last updated October 2012 by Dr Wayne Lam, Consultant Clinical Geneticist, Western General Hospital, Edinburgh, UK.

What are the symptoms?

Associated problems are thought to occur in approximately 70 per cent of patients with the distinct skin markings. These include:

  • neurological problems:

- learning difficulties (see entry Learning Disability)

- seizures

- hemimegalencephaly (enlarged brain on one side)

- retinal pigment abnormalities

- myopia (nearsightedness)

- night blindness

- detached retina

  • orthopaedic problems:

- scoliosis

- hemihypertrophy (asymmetry of growth on either side of the body)

What are the causes?

It is thought the condition occurs due to a change in DNA or chromosomes after the sperm fertilises the egg (a process known as conception).

How is it diagnosed?

Hypomelanosis of Ito is present at birth and is usually picked up by a dermatologist, paediatrician or neurologist during the first year of life. Thorough history taking and physical examination with attention to neurological and ophthalmological (eye) problems is necessary to detect any problems.

When a sample of skin cells from a person affected are grown in the laboratory, an abnormal chromosome pattern is found in about one third of affected individuals.

How is it treated?

The skin effects of hypomelanosis of Ito do not require treatment. In many cases, the skin may develop pigment (colour) over time and blend in well with normal skin. Skin camouflage creams may be used if children are conscious of their appearance.

Neurological problems, orthopaedic problems and ophthalmological problems will need monitoring by the appropriate specialists and treatment given if necessary. Anti-convulsant medication may be required to control seizures.

The appropriate social and educational support will need to be put in place for children with a learning disability.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
This is not an inherited disorder, since the error occurs after conception in one population of cells.

Prenatal diagnosis
This condition is not recurrent (occurring again). Management of future pregnancies should be in families should follow routine guidelines, although detailed ultrasound scanning may provide added reassurance.

Is there support?

HITS (UK) Family Support Group

Tel: 01803 401018 (National Contact)
Tel: 07940 114943 (London Contact)
www.e-fervour.com/hits

The Group is a network of families, originally established in 1991 and re-established in 1999. It offers support and information through a range of resources including a yahoo group, Facebook page and newsletters. The Group holds an annual family day and, where possible, offers links with other similarly affected families.

Group details last updated February 2013.