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Laboratory Test Directory

Alpha-Sarcoglycan (SGCA) Gene Sequencing

Components

Name Method Department Units
Alpha-Sarcoglycan (SGCA) Gene Sequencing Analysis of the entire coding region: Sequence analysis
Polymerase chain reaction (PCR)
Sanger sequencing
DNA extraction
Molecular Genetics

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume
Preferred

Purple tube (EDTA)

4 mL 4 mL-8 mL
Stability

Room temperature - 24 hour(s)
Refrigerated - 72 hour(s)

Specimen Preparation

  • Do not centrifuge
  • Do not freeze

Reasons for Rejection

  • Centrifuged specimen
  • Wrong collection tube
  • Delayed or improper handling
  • Frozen specimen
  • Clotted specimen

Comments

Please click on the Lab Form Link in the Forms Section to print and complete the Genetic Test Requisition Form. Submission of completed Genetic Test Requisition Form is required, and submission of informed consent form is recommended but not required. If available, please also muscle biopsy results.

This test is a full gene sequencing analysis of the SGCA (alpha-sarcoglycan) gene.

Presence of a pathogenic variant (mutation) in both alleles of this gene causes limb-girdle muscular dystrophy (LGMD) type 2D, which is a sarcoglycanopathy type of LGMD and is inherited in autosomal recessive manner. LGMD is a diverse group of disorders affecting the voluntary muscles, mainly around the pelvic (hip) and shoulder regions. In LGMD, the onset of symptoms is in late childhood, adolescence or even adult life. Inheritance in LGMD can be autosomal dominant (LGMD type 1) or autosomal recessive (LGMD type 2). It is sometimes difficult to distinguish the different forms of LGMD based on clinical symptoms alone. Age of onset, progression, and distribution of the weakness and wasting vary considerably among individuals and genetic subtypes. The limb-girdle muscular dystrophies typically show dystrophic changes on muscle biopsy, which is usually associated with elevated serum creatine kinase concentration. Biochemical testing (i.e., protein testing by immunostaining or immunoblotting) performed on a muscle biopsy can establish the diagnosis of the following LGMD types: sarcoglycanopathy, calpainopathy, dysferlinopathy, and dystroglycanopathy. In some cases, demonstration of complete or partial deficiencies for any particular protein can then be followed by mutation studies of the corresponding gene. It is important to note that in some cases, clinical symptoms and mode of inheritance may be more useful than muscle biopsy results.

Forms

Lab Form

CPT Code

  • 81405