Arthrogryposis: Arthrogryposis Multiplex Congenita; AMC

Arthrogryposis Multiplex Congenita (AMC) is not a diagnosis but a descriptive term which is used to describe a baby born with joint contractures affecting at least two different areas of the body. The joints may be fixed in a bent or straightened position. It is believed that such contractures may result from one of several processes that cause the unborn baby's limbs not to move properly at the time the joints are being formed. These processes fall into four main categories: problems with the nerve supply, the muscles, the connective or supporting tissues and external factors such as the blood supply to the baby or the shape of the womb. Approximately 1 in 5,000 babies are affected.

Arthrogryposis includes over one hundred and fifty different conditions. These include diagnoses such as Multiple Pterygium syndrome, Larsen syndrome and Freeman Sheldon syndrome. Some are relatively mild whilst others involve problems with other organs such as the brain, nervous system or muscles.

The commonest cause of AMC is amyoplasia (lack of muscle formation). This too has a recognisable pattern of joint involvement and other features. Although this condition is present at birth, it is non-progressive and it is almost certainly not inherited so that the risk of other children in the family being affected is very low.

The care of people with Arthrogryposis is essentially symptomatic. However early diagnosis is important so that appropriate therapy can planned. This may include early physiotherapy (including passive stretching exercises), splinting and surgery. A referral to a geneticist is also recommend to see if the pattern of problems can be recognised and a specific diagnosis made.

Inheritance patterns
All types of inheritance may be implicated, including chromosomal problems. The family tree may provide clues to how the condition is inherited or passed down through the family. Even after the baby is born it may be difficult to make a specific diagnosis but it is still important that each child is assessed on an individual basis. In this way they can be given the support they need to reach their full potential at each stage of their development.

Prenatal diagnosis
If the specific genetic change that has caused the problems is known, then it may be possible to look for this in subsequent pregnancies by chorionic villus sampling (CVS) or amniocentesis. This is likely to be possible in only a very small minority of cases.

Ultrasound scanning later in the pregnancy may detect contractures or a decrease in fetal movements but it may not be possible to be sure of how severely the baby is likely to be affected.

Medical text written October 1999 by TAG (The Arthrogrypsosis Group). Approved October 1999 by Dr C Pollitt. Last updated October 2004 by Dr C Pollitt, Specialist Registrar in Clinical Genetics, School of Biochemistry and Genetics, University of Newcastle, Newcastle upon Tyne, UK.

THE ARTHROGRYPOSIS GROUP (TAG)

The Arthrogryposis Group (TAG)
Beak Cottage
Dunley
Stourport-on-Severn
DY13 0TZ
Tel: 01299 825781
e-mail taguk@aol.com
Web: http://tagonline.org.uk

The Group is a National Registered Charity No. 327508, established in 1984. It offers support, contact and information for affected children/members and their families. Activities include raising professional and public awareness of the condition; a range of family events organised by regional contacts; a national annual conference; quarterly newsletter and a wide range of information, details on request. The group represents the families of over 400 children and 300 adults who have Arthrogryposis.

Group details last updated October 2007.