In many congenital muscular dystrophy subtypes, muscle weakness can increase with time and can lead to respiratory problems. This may happen in children of various ages and is potentially a very serious complication which, if not recognised, can be life-threatening.
The severity of this condition varies greatly from person to person. As the severity varies even within the same form of congenital muscular dystrophy, it is important not to assume that certain motor developments will or will not take place, but rather to work with children so they can achieve the goals which are within their ability.
Some children will walk, but sometimes this can be delayed until the age of five or older. Leg splints are often used to assist a child to walk. Some children who have achieved independent walking may lose this ability later on because, as they grow older and heavier, the muscles are unable to cope with a greater strain. Other children may not be able to walk at all.
The presence and the severity of other problems depend on the subtype of congenital muscular dystrophy. Some features, however, are generally found in many children with congenital muscular dystrophy, irrespective of the subtype.
As the muscles are weak and mobility is limited, the child may either be born with – or develop – joint ‘contractures’ or tightness. This means that the muscle tendons tighten up, and the child is unable to move the limbs or the joints as freely as a non-affected child can. Physiotherapy can help to prevent or slow the progression of contractures, therefore a programme of exercises should be established with the help of a physiotherapist soon after diagnosis. Hips are commonly affected with contractures and may sometimes be dislocated, which may require treatment with a splint or surgery.
Breathing and feeding problems are commonly observed in some forms of congenital muscular dystrophy but are less frequent in others.
In some subtypes of congenital muscular dystrophy, the function of the brain can be affected and give rise to different degrees of learning difficulties. This complication occurs only in specific subtypes and is not progressive. It will usually be evident in the first year of life, and its severity can vary considerably. However, this complication will not develop at a later stage in children who have average intellectual function.