Alpha Thalassaemia (Alpha Thalassemia - US) - Mental Retardation on the X-Chromosome: Alpha Thalassaemia Mental Retardation syndrome; Mental Retardation on the X-Chromosome; ATR-X

ATR-X syndrome is an inheritable condition which affects boys. The effects of the condition include learning difficulties, a characteristic facial appearance and mild anaemia. The anaemia results from a mild form of thalassaemia similar to, but quite distinct from, ß Thalassaemia (see entry, Thalassaemia Major) which is common in the Mediterranean and South-East Asia and is not associated with learning difficulties. The red blood cells have a tell-tale appearance under the microscope which allows the diagnosis of ATR-X to be confirmed by a simple blood test.

Affected boys have severe learning difficulties and milestones are delayed. Speech is usually not achieved. Affected boys tend to suffer frequent colds and recurring chest infections. Most of the boys have genital abnormalities, most frequently undescended testes. Feeding problems and regurgitation are commonly present. Sleep disturbance and mouthing may occur in some children. World-wide, over one hundred and fifty affected families have been identified with this condition.The underlying gene was identified in 1995.

Inheritance patterns
X-Linked. It is often possible to identify female carriers of the ATR-X syndrome by family studies.

Prenatal diagnosis
This may be possible in some families where there is already one affected family member. Advice from the Regional Genetics Centre may be sought prior to pregnancy.

Medical text written February 1993 by Dr D Higgs and Dr R Gibbons, MRC Molecular Haematology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford UK. Last updated June 2007 by Dr R Gibbons, MRC Molecular Haematology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.

Further Online Resources
Medical texts in The Contact a Family Directory are designed to give a short, clear description of specific conditions and rare disorders. More extensive information on this condition can be found on a range of reliable, validated web sites and links to them are included in the CD-ROM version of this Directory. Further information on these resources can be found in our Medical Information on the Internet article.

ATR-X SUPPORT GROUP

Denise and David Walker
ATR-X Support Group
82 The Crescent
Northwich
CW9 8AD
Tel: 01606 44943
e-mail: davidwalker825@btinternet.com

The group was, established in 1991 and is in contact with Professor Douglas Higgs and Dr Richard Gibbons, the leading authorities on the condition. It offers support for families of affected children and linking of families where possible. The Group maintains a national register of families. It publishes a newsletter and is in touch with the families of 70 affected children and adults in the UK and overseas.

Group details last updated February 2007.