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University of Iowa Diagnostic Laboratories (UIDL) Department of Pathology Room 5231, RCP Iowa City, Iowa 52242-1181 319-384-7212 Tel 319-384-7213 Fax |
AUTOSOMAL RECESSIVE LIMB-GIRDLE
MUSCULAR DYSTROPHY INFORMATION
| Background: |
Limb-girdle muscular dystrophy (LGMD) is a descriptive term for a genetically and clinically heterogeneous group of childhood and adult onset muscular dystrophies distinct from the X-linked dystrophinopathies. Patients show weakness and wasting of limb musculature with more proximal involvement than distal. Onset and severity of symptoms vary widely and are, to some extent, dependent upon the molecular etiology of the disease. Phenotypic variability ranges from early onset and severe presentations similar to a Duchenne-Becker dystrophinopathy, to onset in the 6th or 7th decades of life with only mild symptoms. The p.R77C mutation in the alpha sarcoglycan gene (SGCA) accounts for approximately 32% of all alleles known to cause LGMD type 2D (OMIM 600119). The p.S114F mutation in the beta sarcoglycan gene (SCGB) causes LGMD type 2E (OMIM 600900) and has been shown to be prevalent in the North American population. Sarcoglycanopathies often exhibit early childhood onset with a severe and progressive phenotype similar to that of Duchenne muscular dystrophy. Only one other common AR-LGMD mutation is known. LGMD type 2I is a mild allelic variant of congenital muscular dystrophy (MDC1C, OMIM 606612) caused by mutations in fukutin related protein gene (FKRP). Among European LGMD type 2I patients, the p.L276I allele accounts for approximately 80% of all abnormal alleles. Homozygous p.L276I individuals tend to have milder phenotypes than compound heterozygous patients. |
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| Contact Information: |
UIDL Client Services Monday-Friday - 8:00 am-6:30 pm CST Saturday - 8:00 am-1:00 pm CST Phone - 866-844-2522 Fax - 319-384-7213 Technical Test Information Molecular Pathology Laboratory 319-384-9568 Genetic Counseling Christina Trout, RN Division of Medical Genetics 319-356-4017 |