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Laboratory Test Directory

Myotilin (MYOT) Gene Sequencing

Components

Name Method Department Units
Myotilin (MYOT) Gene Sequencing Polymerase chain reaction (PCR)
Analysis of the entire coding region: Sequence analysis
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
  • Transport to laboratory as soon as possible

Reasons for Rejection

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

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. If available, please also submit muscle biopsy results.

This test is a full gene sequence analysis of the MYOT gene. Presence of a mutation in this gene causes limb-girdle muscular dystrophy (LGMD) type 1A, which is inherited in autosomal dominant manner. This MYOT gene sequencing is done in two tiers. The first tier of the analysis involves sequencing of exon 2. To date, all mutations in the MYOT gene attributed to the limb-girdle muscular dystrophy type 1A (LGMD1A) phenotype have been identified in this exon. If no mutations are observed in this exon, the remaining eight coding exons of the MYOT gene are sequenced in the second tier of the analysis. Limb-girdle muscular dystrophy (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 sometimes is difficult to separate 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.

Targeted mutation analysis available for other family members when mutation known (see test code FMLIS).

 

Forms

Lab Form

CPT Code

  • 81405