Limb-girdle muscular dystrophy

Limb-girdle muscular dystrophy or Erb's muscular dystrophy is an autosomal class of muscular dystrophy that is similar but distinct from Duchenne muscular dystrophy and Becker's muscular dystrophy. Limb-girdle muscular dystrophy encompasses a large number of rare disorders.

Presentation

The term "limb-girdle" is used to describe these disorders because the muscles most severely affected are generally those of the hips and shoulders -- the limb girdle muscles.

Common symptoms of limb-girdle muscular dystrophy are muscle weakness, myoglobinuria, pain, myotonia, cardiomyopathy, elevated serum CK, and rippling muscles.

The muscle weakness is generally symmetric, proximal, and slowly progressive.

Generally pain is not present with LGMD, and mental function is not affected.

LGMD can begin in childhood, adolescence, young adulthood or even later. The age of onset is usually between 10 and 30. Both genders are affected equally. When limb-girdle muscular dystrophy begins in childhood the progression appears to be faster and the disease more disabling. When the disorder begins in adolescence or adulthood the disease is generally not as severe and progresses more slowly.

There is no sensory neuropathy or autonomic or visceral dysfunction at presentation.the specific dermatomes affected can be demonstrated clinically,and although lower limb deep tendon reflexes and plantar reflex are lost, abdominal reflexes are preserved

Prognosis

The distal muscles are affected late in LGMD, if at all. Over time (usually many years), the person with LGMD loses muscle bulk and strength. Eventually, s/he may need a power wheelchair or scooter, especially for long distances.

While LGMD isn't a fatal disease, it may eventually weaken the heart and lung muscles, leading to illness or death due to secondary disorders.

Genetics

LGMD is typically an inherited disorder, though it may be inherited as a dominant, recessive, or X-linked genetic defect. The result of the defect is that the muscles cannot properly form the proteins needed for normal muscle function. Several different proteins can be affected, and the specific protein that is absent or defective identifies the specific type of muscular dystrophy.

Treatment

Treatment for LGMD is primarily supportive. Exercise and physical therapy are advised to maintain as much muscle strength and joint flexibility as possible. Calipers may be used to maintain mobility and quality of life. Careful attention to lung and heart health is also required. IVIg may increase strength in some forms and prevent progression in others, possibly through the prevention of fibrosis and inflammation without the secondary weakening caused by corticosteroids.

List of limb-girdle muscular dystrophies

The "LGMD1" family is autosomal dominant, and the "LGMD2" family is autosomal recessive.

External links

• Muscular Dystrophy Association
• LGMD in MDA website
• GeneReview/NIH/UW entry on Limb-Girdle Muscular Dystrophy Overview
• Healthline for Patients
• Washington University in St. Louis Neuromuscular Section LGMD
• Duke University (Great Clinical Description of LGMD phenotypes
• Glenn Lopate MD for emedicine
• Jain Foundation Inc:Orchestrating a cure for Miyoshi/LGMD2B