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Reviewed April 2011

What is the official name of the SGCA gene?

The official name of this gene is “sarcoglycan alpha.”

SGCA is the gene's official symbol. The SGCA gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the SGCA gene?

The SGCA gene provides instructions for making the alpha component (subunit) of a group of proteins called the sarcoglycan protein complex. The sarcoglycan protein complex is located in the membrane surrounding muscle cells. It helps maintain the structure of muscle tissue by attaching (binding) to and stabilizing the dystrophin complex, which is made up of proteins called dystrophins and dystroglycans. The large dystrophin complex strengthens muscle fibers and protects them from injury as muscles tense (contract) and relax. It acts as an anchor, connecting each muscle cell's structural framework (cytoskeleton) with the lattice of proteins and other molecules outside the cell (extracellular matrix).

How are changes in the SGCA gene related to health conditions?

limb-girdle muscular dystrophy - caused by mutations in the SGCA gene

More than 70 mutations in the SGCA gene have been identified in people with limb-girdle muscular dystrophy type 2D. Limb-girdle muscular dystrophy is a group of related disorders characterized by muscle weakness and wasting, particularly in the shoulders, hips, and limbs. Forms of limb-girdle muscular dystrophy caused by gene mutations that affect the sarcoglycan complex are called sarcoglycanopathies.

The most common SGCA gene mutation occurs in about one-third of people with limb-girdle muscular dystrophy type 2D. This mutation replaces the protein building block (amino acid) arginine with the amino acid cysteine at position 77 in the alpha-sarcoglycan protein, written as Arg77Cys or R77C. The rest of the known SGCA gene mutations are specific to individual families or certain populations.

SGCA gene mutations may prevent the sarcoglycan complex from forming or from binding to and stabilizing the dystrophin complex. Problems with these complexes reduce the strength and resilience of muscle fibers and result in the signs and symptoms of limb-girdle muscular dystrophy.

Where is the SGCA gene located?

Cytogenetic Location: 17q21

Molecular Location on chromosome 17: base pairs 50,165,975 to 50,175,932

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The SGCA gene is located on the long (q) arm of chromosome 17 at position 21.

The SGCA gene is located on the long (q) arm of chromosome 17 at position 21.

More precisely, the SGCA gene is located from base pair 50,165,975 to base pair 50,175,932 on chromosome 17.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about SGCA?

You and your healthcare professional may find the following resources about SGCA helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the SGCA gene or gene products?

  • 50DAG
  • 50-DAG
  • 50 kDa dystrophin-associated glycoprotein
  • 50kD DAG
  • adhalin
  • ADL
  • alpha-sarcoglycan
  • alpha-SG
  • DAG2
  • DMDA2
  • dystroglycan-2
  • LGMD2D
  • sarcoglycan, alpha (50kDa dystrophin-associated glycoprotein)
  • SG-alpha

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding SGCA?

amino acid ; arginine ; cell ; cysteine ; cytoskeleton ; extracellular ; extracellular matrix ; gene ; injury ; muscle cell ; muscle cells ; muscular dystrophy ; mutation ; protein ; resilience ; subunit ; tissue ; wasting

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (11 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: April 2011
Published: February 1, 2016