Types of Arthrogryposis

There are more than 300 conditions that come under the Arthrogryposis ‘umbrella’ and these can be divided into  three groups:

  • disorders with mainly limbs
  • disorders with limb plus some other body area e.g. cleft palate, the heart, intestinal defects, curvature of the spine
  • disorders with limb  and the central nervous system

Mainly limb

Amyoplasia is the most common type of AMC condition and is known as ‘classical Arthrogryposis’.  It occurs in 1 in every 10,000 live births and represents one-third of all cases of people diagnosed with Arthrogryposis.  Usually, people are affected in all four limbs but there are cases where only a person’s legs or arms are affected.  About 10% of people with Amyoplasia have some type of intestine or abdominal wall abnormality but this responds well to early physical therapy.

It is not seen as a genetic condition, but parents of a baby with Amyoplasia are advised to seek genetic counselling for their child as they approach adulthood.

With Distal Arthrogryposis Type I, it is the hands and feet that are usually the most severely affected. In a newborn baby, the characteristics of the disorder can clearly be seen as the hands are clenched and the fingers overlap.  Feet can also be affected along with the knees and hips but this is usually fairly mild.  Again, it has a relatively good response to early physical therapy.

This type has an autosomal dominant inheritance and, as only one parent must have an abnormal gene in order for the child to inherit the disease, there is a 50/50 chance of passing it on.

Limbs plus other body areas – Multiple Pterygium Syndromes

A pterygium is a winglike structure, web or triangular membrane that forms across a body joint. There are many types of pterygium syndrome but individuals with these conditions often have webs of skin at their neck, knees and elbows as well as multiple congenital contractures. Blood vessels and nerves run along the edge of this web and so much care is needed when operating.

Each of the different pterygium syndromes has a different form of inheritance.

Freeman Sheldon Syndrome (Whistling Face Syndrome)

As well as contractures of the hands and feet this condition also has facial involvement. The muscles are contracted in such a way as to give a ‘whistling’ appearance. In the most severe cases, the mouth may have extremely limited movement. Even when the face is not so affected it might still be difficult for the individual to smile and there is often postnatal growth deficiency within this group.

Distal Arthrogryposis Type II B

This type of DA also has the features of paralysis to all or part of the eye and eyelids may appear droopy. As well as muscle weakness around the eyes, the eyes themselves may have limited movement, especially to the sides. Skin and muscles are hard and there is a lack of finger creases.

This type is autosomal dominant and quite common.

Distal Arthrogryposis Type II C

This type of DA also has the feature of a cleft lip.

Distal Arthrogryposis Type II D

With this type of DA, there is also scoliosis (curvature of the spine).

Distal Arthrogryposis Type II E

This type of DA has a characteristic positioning of the hand in which the wrist is flexed but the metacarpal phalangeal joint (palm to wrist) is extended. There is limited opening of the jaw (trismus).

DA Type IIE is relatively common and does not run in families.

Limbs plus Central Nervous System

Babies in this category tend to do very poorly and may not survive. Sadly, this is usually quite obvious in the neonatal (first 28 days) and is not something that develops at a later stage.