Ordering Recommendation

Appropriate first-tier genetic test for diagnostic testing or carrier screening for Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD); does not detect sequence variants. Recommended test for a known familial DMD large deletion or duplication previously identified in a family member.

Mnemonic

DMD DD

Methodology

Multiplex Ligation-dependent Probe Amplification

Performed

Varies

Reported

7-14 days

New York DOH Approval Status

Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.

Specimen Required

Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Preferred transport temp: Refrigerated. Also acceptable: Room temperature.

Unacceptable Conditions
Remarks
Stability

Room temperature: 1 week ; Refrigerated: 1 month; Frozen: Unacceptable

Reference Interval

By Report

Interpretive Data

Background information for Duchenne/Becker Muscular Dystrophy (DMD) Deletion/Duplication:
Characteristics
: Symptoms of Duchenne muscular dystrophy (DMD) usually begin before age 6 and include fatigue, learning difficulties, muscle weakness (beginning in legs and pelvis), progressive difficulty walking with wheelchair needed at approximately 12 years and breathing difficulties and heart disease by age 20 years. Symptoms of Becker muscular dystrophy (BMD) are similar to DMD but start later and progress at a slower rate. Dilated cardiomyopathy has been observed in nearly all affected males and many female carriers of DMD and BMD.
Incidence
: DMD: 1 in 3,500 male births, BMD: 1 in 19,000 male births.
Inheritance
: X-linked; de novo mutations occur in one-third of cases.
Penetrance
: Males: 100 percent. Females: Varies with X-chromosome inactivation.
Cause
: Pathogenic DMD mutations.
Clinical Sensitivity:
DMD: 55-75 percent, BMD: 75-90 percent. 
Methodology
: Multiplex ligation-dependent probe amplification (MLPA) to detect large exonic deletions/duplications.
Analytical Sensitivity and Specificity
: Greater than 99 percent.
Limitations
: DMD base pair substitutions, small deletions/duplications, deep intronic, and regulatory region mutations will not be detected. Breakpoints for large deletions/duplications will not be determined. Diagnostic errors can occur due to rare sequence variation.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Laboratory Developed Test (LDT)

Note

Hotline History

N/A

CPT Codes

81161

Components

Component Test Code* Component Chart Name LOINC
2011236 Duchenne/Becker MD (DMD) DelDup Specimen 66746-9
2011237 Duchenne/Becker MD (DMD) DelDup Interp 21247-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

Duchenne/Becker Muscular Dystrophy (DMD) Deletion/Duplication