Myotonic Dystrophy 1 (DMPK) Genetic Testing (Repeat Expansion)

Whole blood, oral swab, extracted DNA (from blood or oral swab only)

Whole blood: 4 ml
Oral swab: 3 swabs
Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST) 

Whole blood: 2 ml
Oral swab: 1 swab
Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST)

Whole blood: Lavender-top (EDTA) 
Oral swab: OCD-100 DNA Genotek
Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST)

Whole blood: standard phlebotomy. 
Oral swab: follow kit instructions
Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST)

Maintain specimen at room temperature or refrigerate at 4°C. Do not freeze. 

• Room temperature: Whole blood: 14 days; Swab: 60 days
• Refrigerated: Whole blood: 30 days; Swab: 60 days
• Frozen: Do not freeze

Frozen or hemolyzed specimen; quantity not sufficient for analysis; improper container

Type 1 myotonic dystrophy results from a mutation in the DMPK gene known as a trinucleotide repeat expansion. This mutation increases the size of the repeated CTG segment in the DMPK gene. People with type 1 myotonic dystrophy have from 50 to 5,000 CTG repeats in most cells. The number of repeats may be even greater in certain types of cells, such as muscle cells.

False positive or false negative results may occur for reasons that include insufficient information available about rare genetic variants, allele dropout, blood transfusions, bone marrow transplantation, somatic or tissue-specific mosaicism, or mislabeled samples. Maximum reportable size of repeat expansion testing: ATN1: 110 repeats; ATXN1: 150 repeats (repeats greater than 40 in the ATXN1 gene cannot be assessed for CAT interruptions); ATXN2: 150 repeats; ATXN3: 120 repeats; ATXN7: 125 repeats; ATXN8/ATXN8OS: 150 repeats; ATXN10: 70 repeats; C9orf72: 65 repeats; CACNA1A: 145 repeats; CNBP: 373 base pairs (approximately 75 repeats); DMPK: 150 repeats; FXN: 1300 repeats; HTT: 100 repeats; JPH3: 100 repeats; NOP56: 65 repeats; PPP2R2B: 150 repeats; TBP: 120 repeats. Repeat sizes greater than the maximum reportable range are reported as greater than the largest reportable repeat size.       
                                                                                                                                                                                                                      This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

Repeat-Primed PCR and fragment length analysis to identify number of nucleotide repeats
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SINGLE Blood Genetic Testing, Buccal Swab Genetic Testing