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Facioscapulohumeral Muscular Dystrophy Test

Important Note

Please order as a MISCELLANEOUS test.  A completed requisition and clinical history details are required (see link below).

Clinical System Name

Miscellaneous Test Communication Order


Facioscapulohumeral muscular dystrophy (FSHD) typically presents before age 20 years with weakness of the facial muscles and the stabilizers of the scapula or the dorsiflexors of the foot. Severity is highly variable. Weakness is slowly progressive and approximately 20% of affected individuals eventually require a wheelchair. Life expectancy is not shortened.


Approximately 90% of individuals affected with FSHD have a chromosome 4q35 deletion. The identification of a characteristic 4q35 deletion is more than 90% specific for the disease. Furthermore, patients with FSHD have 4qA alleles. A deleted 4q35/4qA allele is diagnostic of FSHD type 1 (FSHD1). Approximately 5% of FSHD patients have FSHD type 2. These patients have non-deleted 4qA alleles, hypomethylation of D4Z4 repeats, and a heterozygous dominant mutation in the SMCHD1 gene.

Sample Requirements

Specimen: Whole Blood

Container(s): Lavender Top/EDTA

Preferred Vol: 15 mL

Minimum Vol: 10 mL


Notes:  Testing requires a dedicated collection tube (cannot share with other tests). Extracted DNA is NOT acceptable.

Processing Instructions

Reject due to:

Spin: N

Aliquot: N

Temp: 2-8 C

Storage location: CPA refrigerator send-outs rack.


Off-site collection: Send whole blood refrigerated.


Specimen Type Temperature Time
Whole blood Room temp 24 h
Whole blood Refrigerated 2 d
Whole blood Frozen N



N 21 d *


*21 days for routine FSHD1 testing or subsets of FSHD2 testing; at least 6 weeks for complete FSHD1 and FSHD2 testing.

Performing Laboratory

UI Diagnostic Laboratories


Department:  UI Diagnostic Laboratories, Department of Pathology, 200 Hawkins Drive, 5231 RCP, Iowa City, IA,  52242

Phone Number: (866) 844-2522

Reference Range

Interpretive report is provided.


Method: Southern blot; DNA sequencing

Details: Peripheral blood leukocytes embedded in agarose plugs are digested with specific restriction enzymes. The restriction fragments are separated by pulsed field gel electrophoresis and detected by Southern blot probed with p13E-11. As needed, the Southern blot is rehybridized with a D4Z4 probe. To determine the 4qA/4qB allele status of each restriction fragment, similar Southern blots are hybridized with 4qA or 4qB probes. Additional testing for FSHD2 involves determining the methylation status of the D4Z4 repeats, another Southern blot assay that uses isolated DNA. In patients with a permissive 4qA allele and an appropriate level of hypomethylation, mutation analysis of the SMCHD1 gene is performed on a next generation sequencing platform.

Send Out Instructions

Reference Test Name: Facioscapulohumeral Dystrophy (FSHD)
Reference Test Number: FSHD
Instructions: Ship ambient temperature Priority Overnight via FedEx to UIDL.Shipe on Mondays, Tuesdays, or Wednesdays only, to avoid potential weekend deliveries.