Background:
Neuromuscular disorders are a group of heterogeneous conditions affecting the nervous system that controls muscle movements. Congenital myopathies are a group of genetic conditions and can be autosomal dominant, recessive or X-linked. Typical clinical manifestations include hypotonia, muscle weakness, and delayed motor developmental milestones. Cardiac conditions and joint dislocations can also be observed. This test includes genes associated with central core disease, nemaline myopathy, and myotubular myopathy.
Reasons for Referral:
- Abnormal serum creatine kinase levels
- Delayed movement milestones
- Muscle weakness with signs of structural abnormalities of myofibers observed in biopsy
- Abnormal electromyography (EMG)
- Abnormal nerve conduction studies (NCS)
- Positive family history (targeted testing is available if familial mutation is known)
- Carrier testing
Methodology:
This test has two components:
Component 1: Next generation sequencing will analyze the exons or coding regions of 15 Congenital Muscular Myopathy-associated genes using Illumina NextSeq 500 technology and preparing samples using hybridization probes to enrich exonic regions. Promoter, intronic, etc. regions are not assessed here but may contain variants that impact gene function.
Component 2: A customized CytoSure “exon-centric” array (Oxford Gene Technology) will be used to detect deletions and duplications. The targeted array has enhanced probes targeted to the exonic regions of the 15 Congenital Muscular Myopathy-associated genes. The arrays will be run using Agilent SureScan technology. This array is an ideal complement to the next generation sequencing approach to provide a comprehensive mutation spectrum analysis for Congenital Muscular Myopathy.
Congenital Muscular Myopathy Panel (15 genes): ACTA1, BIN1, CFL2, CNTN1, DNM2, KBTBD13, MTM1, MYF6, MYH7, NEB, RYR1, SEPN1, TNNT1, TPM2, TPM3
Specimen Requirements:
Blood: EDTA or ACD (Solution A or B):
- Adult: 5 mL
- Child: 5 mL
- Infant: 2-3 mL
DNA: 10µg at a minimum of 60-100ng/µL (DNA must be extracted in a CLIA-certified laboratory or a laboratory meeting equivalent requirements as determined by the CAP and/or CMS)
For routine testing of blood, saliva and buccal swabs, KDL does NOT accept samples from patients within two (2) weeks of a packed cell/platelet transfusion or within four (4) weeks of a whole blood transfusion. For extraordinary circumstances, where testing must be performed outside of the above windows, please contact our lab.
A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES. Please include detailed clinical information, including ethnicity, clinical history, and family history.
Test Performed (Days):
Turn Around Time:
Shipment Sensitivity Requirements:
- Package and ship specimen to remain cold, but not frozen.
- Ship via overnight express, using the FedEx priority overnight label provided.
- Contact Client Services for shipping kits and instructions at (855) 535-1522.
References:
- Curr Opin Neurol. 2001 Oct;14(5):575-82. GeneReviews
Additional Info: