Friedreich's Ataxia: Recessive Spino-Cerebellar Degeneration

Friedreich's Ataxia is a genetic disorder characterised by a progressive degeneration of the spino-cerebellar system due to an abnormality of a gene on chromosome 9 (called Frataxin). The first sign of the disorder is unsteadiness of gait (ataxia). The onset of the condition is variable but usually occurs between the ages of four and sixteen (but occasionally between eighteen months and thirty years). Although most cases present under the age of twenty-five very rarely it may produce with an ataxia of much later onset. Onsets into the sixth and seventh decades have been found. Therefore it is worth considering even in older patients if some of the other clinical hallmarks are present.

The genetic abnormality (mutation) in the majority of patients (ninety-five per cent plus) is an abnormally long repetition of a DNA fragment (expansion) in the Friedreich ataxia genes in both chromosomes 9. This mutation can be readily detected using a variety of molecular methods. However a small percentage (less than five per cent) may just have one expansion in one copy of their gene and the other copy may have a much more subtle abnormality called a point mutation. These latter abnormalities are more difficult to detect and need to be specially requested from the laboratory.

The onset of the condition is insidious and affects co-ordination of the muscles used in speech, the arms and legs. Scoliosis may also be a feature of the disorder, as may an enlarged heart or diabetes.

Inheritance patterns
Autosomal recessive

Prenatal diagnosis
It is now possible to offer, by means of blood tests, carrier detection, prenatal and pre-symptomatic diagnosis in families with an affected child. These tests are only available to those families with an affected member. In such families genetic advice should be sought where a pregnancy is under consideration. Chorionic villus sampling is available at ten to twelve weeks.

Medical text written November 1991 by Contact a Family. Approved November 1991 by Professor M Patton, Professor of Medical Genetics, St Georges Hospital Medical School, London, UK and Dr J E Wraith, Consultant Paediatrician, Royal Manchester Children's Hospital, Manchester, UK. Last updated November 2005 by Dr P Giunti, Senior Clinical Fellow, University Department of Clinical Neurology, University College, London, 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.

ATAXIA UK

Ataxia UK
Winchester House
11 Cranmer Road
London
SW9 6EJ
Tel: 0845 644 0606 Lo-Call Helpline
Tel: 020 7582 1444 Office
Fax: 020 7582 9444
e-mail: office@ataxia.org.uk
Web: http://www.ataxia.org.uk

Ataxia UK is a National Registered Charity No. 1102391, established in 1964. It supports people affected by Friedreich's, cerebellar and other ataxias. Ataxia UK helps people with ataxia, their carers, families and friends, to live with the condition. It provides information through leaflets, magazines, reports and the website; an information and support helpline; branches, self-help groups and meetings; personal contacts; and welfare grants. It also supports medical and scientific research into causes and potential treatments. Information about this under-diagnosed condition is also available for healthcare and social service professionals.

Group details last confirmed October 2007.