Limb-Girdle Muscular Dystrophy (LGMD)
Signs and Symptoms
Major clinical features of LGMDs are progressive weakness and muscle atrophy mainly involving the shoulder girdle (scapulohumeral type), the pelvic girdle (pelvifemoral type), or both. Most childhood-onset cases have a pelvifemoral distribution of weakness. Adult-onset disease usually involves both shoulder and pelvic girdles with gradually increasing proximal limb (close to the body core) weakness. Facial weakness is usually mild or totally absent.
Extraocular muscles (muscles that control the movement of the eye) are completely spared in the LGMDs. Distal muscle (away from the core of the body) strength is usually preserved, even at the late stage of the disease, but distal muscle weakness can be an early or prominent feature in some LGMD subtypes.
The presentation of LGMD1s shows greater clinical heterogeneity, later age of onset, more gradual progression, and a creatine kinase elevation that may be minimal compared with LGMD2s.
An affected child with autosomal recessive LGMD, particularly one with LGMD2I, may be indistinguishable on examination from a child with Duchenne or Becker muscular dystrophy. However, unlike Duchenne muscular dystrophy, cognitive function is typically normal in children with autosomal recessive LGMD.
Often, people with LGMD first notice a problem when they begin to walk with a “waddling” gait because of weakness of the hip and leg muscles. They may have trouble getting out of chairs, rising from a toilet seat, or climbing stairs.
Weakness in the shoulder area may make reaching over the head, holding the arms outstretched, or carrying heavy objects difficult. It may become increasingly hard to keep the arms above the head for such activities as combing hair or arranging things on a high shelf. Some people find it harder to type on a computer or other keyboard and may even have trouble feeding themselves.
Assistive devices, such as a cane or a long-handled reacher, can make things easier as weakness progresses.
A power wheelchair or scooter becomes convenient when weakness in the pelvic girdle and upper legs causes frequent falls. People whose LGMD has reached this stage often find that a great deal of their independence returns, and they are much less fatigued, when they begin using this type of vehicle.
The heart can be affected in LGMD, but this does not occur as often as it does in some other forms of muscular dystrophy. Heart problems can take two forms — weakness of the heart muscle (cardiomyopathy) and abnormal transmission of signals that regulate the heartbeat (conduction abnormalities or arrhythmias). The heart should be monitored for these complications. When necessary, medications or devices (such as pacemakers) can be used to treat them.
Respiratory (breathing) function can decline over time, and this, too, should be monitored regularly. There are devices that can help sustain respiratory function.
LGMD, like other muscular dystrophies, is primarily a disorder of voluntary muscles. These are the muscles people use to move the limbs, neck, trunk, and other parts of the body that are under voluntary control.
The involuntary muscles, except for the heart (which is a special type of involuntary muscle), are not affected in LGMD. Digestion, bowel and bladder functions, and sexual function, which are carried out by involuntary muscles, remain normal.
Pain is not a major part of LGMD, although limited mobility sometimes leads to muscle soreness and aching joints. Exercises to keep joints limber, moving around as much as possible, warm baths, and, if needed, medication can keep this kind of discomfort to a minimum.
The brain, the intellect, and the senses are usually unaffected in LGMD. People with LGMD can think, see, hear, and feel sensations the same as those without muscular dystrophy. Although, intellectual disability is a feature of LGMD2K and has been reported in LGMD2N.
Serum creatine kinase concentration is usually modestly elevated in LGMD. However, it can be very high in some LGMD subtypes like sarcoglycanopathy, dysferlinopathy, and caveolinopathy.
To learn more, read The Changing Landscape of LGMD Research.