Limb-girdle muscular dystrophies include at least 18 different inherited disorders, which first affect the muscles around the shoulder girdle and hips. These diseases get worse, and may eventually involve other muscles.
Muscular dystrophy - limb-girdle type (LGMD)
Causes, incidence, and risk factors
Limb-girdle muscular dystrophies are a large group of genetic diseases in which there is muscle weakness and wasting (muscular dystrophy).
In most cases, both parents must pass on the non-working (defective) gene for a child to have the disease (autosomal recessive disorder). However, in some rare types only one parent needs to pass on the bad gene to affect the child (autosomal dominant disorder). For some of these conditions, the defective gene has been discovered. For others, the gene is not yet known.
Typically, the first sign is pelvic muscle weakness (difficulty standing from a sitting position without using the arms, difficulty climbing stairs). The weakness starts in childhood to young adulthood.
Other symptoms include:
Abnormal, sometimes waddling, walk
Joints that are fixed in a contracted position (late in the disease)
Large and muscular-looking calves (pseudohypertrophy), which are not actually strong
Loss of muscle mass, thinning of certain body parts
In general, people tend to have weakness that slowly gets worse in affected muscles and spreads.
The disease causes loss of movement or dependence on a wheelchair within 20 - 30 years.
Heart muscle weakness and abnormal electrical activity of the heart can increase the risk of palpitations, fainting, and sudden death. Most patients with this group of diseases live into adulthood, but do not reach their full life expectancy.
Abnormal heart rhythms
Contractures of the joints
Difficulties with activities of daily living due to shoulder weakness
Progressive weakness, which may lead to needing a wheelchair
Calling your health care provider
Call your health care provider if you or your child feel weak while rising from a squatting position. Call a geneticist if you or a family member has been diagnosed with muscular dystrophy and you are planning a pregnancy.
Genetic counseling may guide some families about their risks and help with family planning.
Some of the complications can be prevented with appropriate treatment. For example, a cardiac pacemaker or defibrillator can significantly reduce the risk of sudden death due to an abnormal heart rhythm. Physical therapy may be able to prevent or delay contractures and improve quality of life.
Affected people may want to do DNA banking. DNA testing is recommended for those who are affected, in order to identify the family gene mutation. Once the mutation is found, prenatal DNA testing, testing for carriers, and preimplantation genetic diagnosis are possible.
Sarnat HB. Muscular dystrophies. In: Kliegman RM, Stanton BM, St. Geme J, Schor N, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; chap 601.
Chad Haldeman-Englert MD, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.