Clinical Indication ID & Name
Myotonic dystrophy type 2 (DM2)
Test Group
Neurology
Specialties
Test code
R410.1
Test name
N/A
Target genes
CNBP (ZNF9) STR
Test scope
n/a
Test method/ technology
STR testing
Optimal Family Structure
n/a
Eligibility Criteria
1. Adult with muscle weakness, usually proximal, and one of the following:
a. Clinical Myotonia: of grip or on percussion
b. EMG evidence of myotonic discharges
c. Cataracts (fine dust like opacities on the outer layers of the lens that are highly coloured and iridescent, producing a “Christmas Tree” appearance)
d. Three or more supportive features (from list below)
e. Family History suggestive of autosomal dominant inheritance
2. AND DM1 excluded first if the clinical presentation/Family history could easily fit DM1
3. OR Family history of mutation positive DM2
Additional supportive features:
• Elevated serum CK
• Insulin-insensitive type 2 diabetes
• Testicular failure
• Cardiac conduction defects
• Low serum IgG or IgM
• Muscle biopsy showing atrophic fibres and proliferation of fibres with central nuclei
• Excessive daytime sleepiness
• Mildly elevated liver function tests (LFT)
• Muscle pain
Commissioning group
Specialised
Overlapping idications
• R72 Myotonic dystrophy type 1 should be used prior to this indication unless there is clinical suspicion of myotonic dystrophy type 2 • R381 Other rare neuromuscular disorders should be used where clinical features are atypical and a broader range of genes are potentially causative
Address for samples/request forms
Genetics Laboratory
5th Floor Tower Wing
Guy’s Hospital
London
SE1 9RT
Contact with queries
Supporting documents
n/a
Education resources
n/a
Turn around times
All our turnaround times are listed on our specific turn around page https://southeastgenomics.nhs.uk/professionals/service-turn-around-times/
Request form download
Consent record
See consent guidance in test request form
Sample requirements
Samples may be rejected for the following reasons: 1.Samples and request form do not show at least three identical patient identifiers 2.The sample is in the incorrect collection media 3.The request form is not sufficiently completed 4.The sample is not of sufficient volume 5.The sample is too old