This distribution of muscle weakness is sometimes referred to as ‘scapulo-humeroperoneal’.
At first there is difficulty in raising the arms above the head and lifting heavy objects, and a tendency to trip over carpets. Later on the hip and thigh muscles also become affected so that climbing stairs becomes increasingly difficult, as does rising from a chair without assistance.
How is the heart affected?
This is affected in a way that is unusual for muscular dystrophy, rather than affecting the heart muscle, it is the electrical wiring (called the cardiac conduction system) that controls the rate at which the heart beats that is mainly involved and is referred to as “heart block”.
The heart rate is often abnormally slow, palpitations may occur (which feel like “fluttering” in the chest – this is not uncommon in normal individuals and alone would not be a cause for concern), as well as attacks of giddiness and fainting spells. Increasing tiredness and breathlessness may also occur.
How severe is the condition?
In general the condition is less severe than many other forms of muscular dystrophy and though life expectancy may be shortened, many affected individuals can expect to reach middle age or later. However, it is essential that affected individuals be checked at frequent intervals, say every 12 months, to ensure that the heart is not affected. There is evidence that a more severe recessive form also exists. Here weakness is present and progresses rapidly from early childhood, however this is very rare.
The condition progresses very slowly over the years (except for the very rare recessive form), and it may be that later in life a wheelchair may be required.