Coverage Policy Manual
Policy #: 2013027
Category: Medicine
Initiated: August 2013
Last Review: August 2018
  Genetic Test: Facioscapulohumeral Muscular Dystrophy

Description:
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease that typically presents before the age of 20 with weakness of the facial muscles and the scapular stabilizer muscles, however, atypical presentations occur. The clinical course is usually of slowly progressive weakness, although the severity is highly variable. Approximately 95% of individuals with FSHD have contraction mutation of the D4Z4 locus. For the 5% of individuals with FSHD who do not have a contraction mutation of the D4Z4 locus, mutations in the gene SMCHD1 have been associated with FSHD.
 
 
Description of the disease
Facioscapulohumeral muscular dystrophy (FSHD) is the third most common muscular dystrophy and involves progressive weakness and wasting of the facial muscles (facio), and shoulder and upper arm (scapulohumeral) muscles. The weakness is often most evident in the muscles of the face, resulting in difficulty smiling and whistling, and reduced facial expression. The weakness in the shoulder muscles causes the scapula to protrude from the back (“winging of the scapula”). The muscles are typically affected asymmetrically, and with progression, the lower extremities, both proximal and distal, become involved (van der Maarel, 2011). The severity of the disease is highly variable, ranging from mildly affected, asymptomatic individuals to severely affected individuals, with approximately 20% of patients eventually requiring a wheelchair. Non-muscular manifestations include retinal vascular abnormalities which can result in significant loss of vision, however, only about 1% of patients with FSHD experience visual acuity loss (van der Maarel, 2011).  Most people with FSHD will eventually develop high-frequency hearing loss, which is usually not noticeable, and only detected by audiogram. FSHD usually presents between the ages of 6 and 20 years, and life expectancy is not shortened. It is estimated that 4-5 people per 100,000 population have FSHD. FSHD affects males and females equally.
 
Clinical diagnosis of FSHD
FSHD has a characteristic distribution of muscle involvement that often can lead to targeted genetic testing without the need for a muscle biopsy (Menezes, 2012). However, atypical presentations have been reported, which include scapulohumeral dystrophy with facial sparing (Lemmers, 1993; Pastorello, 2012). A retrospective review of an academic center database of the period 1996 to 2011 determined that, of 139 genetically confirmed FSHD cases, 7 had atypical disease, including late age of onset of disease, focal weakness and dyspnea (Hassan, 2012).
 
Electromyography (EMG) and muscle biopsy to confirm the clinical diagnosis of FSHD has largely been supplanted by genetic testing. EMG usually shows mild myopathic changes, and muscle biopsy most often shows nonspecific chronic myopathic changes.
 
Genetics of FSHD
FSHD is likely to be caused by inappropriate expression of the gene DUX4 in muscle cells. DUX4 is a double homeobox-containing gene (a homeobox gene being one in a large family of genes that direct the formation of many body structures during early embryonic development). DUX4 lies in the macrosatellite repeat D4Z4, which is on chromosome 4q35. D4Z4 has a length of 11-100 repeat units on normal alleles. The most common form of FSHD (95%) is designated FSHD1, and these individuals have a D4Z4 allele of between one and ten repeat units (Lemmers, 1993). There is no absolute linear and inverse correlation between residual repeat size and disease severity and onset, however, patients with repeat arrays of 1-3 units usually have an infantile onset and rapid progression, (van der Maarel, 2011) The remaining 5% of patients who don’t have FSHD1 are designated as FSHD2, which is clinically indistinguishable from FSHD1. Patients with FSHD2 show loss of DNA methylation and heterochromatin markers at the D4Z4 repeat that are similar to patients with D4Z4 contractions (FSHD1), suggesting that a change in D4Z4 chromatin structure unifies FSHD1 and FSHD2. Mutations in the SMCHD1 gene on chromosome 18, which encodes a protein known as structural maintenance of chromosomes flexible hinge domain containing 1, have been associated with FSHD2. Reductions in SMCHD1 gene product levels have been associated with D4Z4 contraction-independent DUX4 expression, suggesting that SMCHD1 acts as an epigenetic modifier of the D4Z4 allele (Lemmers, 2012b). SMCHD1 has also been identified as a possible modifier of disease severity in patients with FSHD1 (Sacconi, 2013). FSHD is inherited in an autosomal dominant manner. Approximately 70-90% of individuals inherit the disease-causing deletion from a parent, and 10-30% have FSHD as a result of a de novo deletion (Lemmers, 1993).
 
Treatment of FSHD
There is currently no treatment or prevention of symptoms of FSHD, and clinical management is directed at surveillance to identify possible FSHD-related complications, such as hearing loss, and to improve quality of life (e.g., assist devices, physical therapy, orthoses to improve mobility and prevent falls).
 
Commercially available testing for FSHD
The methodology for testing for FSHD1 uses pulsed field gel electrophoresis and southern blot to detect deletions on chromosome 4q35. Testing is only available for FSHD1.
 
Laboratories that offer FSHD1 testing include Athena Diagnostics and the University of Iowa Diagnostic Laboratories.
 
Coding
CPT code 81404 includes the following testing for FSHD:
 
FSHMD1A (facioscapulohumeral muscular dystrophy 1A) (e.g., facioscapulohumeral muscular dystrophy), evaluation to detect abnormal (e.g., deleted) alleles
 
FSHMD1A (facioscapulohumeral muscular dystrophy 1A) (e.g., facioscapulohumeral muscular dystrophy), characterization of haplotype(s) (i.e., chromosome 4A and 4B haplotypes)
  
 

Policy/
Coverage:
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
Genetic testing for facioscapulohumeral muscular dystrophy meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes and is covered to confirm a diagnosis in a patient with clinical signs of the disease.
 
*Note: FSHD is typically suspected in an individual with the following: weakness that predominantly involves the facial, scapular stabilizer, and foot dorsiflexor muscles without associated ocular or bulbar muscle weakness, and age of onset usually by 20 years of age (although mildly affected individuals show signs at a later age and some remain asymptomatic) (Lemmers, 1993).  
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
Genetic testing for facioscapulohumeral muscular dystrophy for all other indications does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes.
 
For members with contracts without primary coverage criteria, genetic testing for facioscapulohumeral muscular dystrophy for all other indications is considered investigational. Investigational services are specific contract exclusions in most member benefit certificates of coverage.
 
 
 
 

Rationale:
This policy was created in 2013 and is based on a search of the MEDLINE database through June 2013. Literature that describes the analytic validity, clinical validity, and clinical utility of testing for FSHD was sought.
 
Analytic validity (the technical accuracy of the test in detecting a mutation that is present or in excluding a mutation that is absent)
 
Published data on the analytic validity of testing for FSHD is not identified.
 
Clinical validity (the diagnostic performance of the test [sensitivity, specificity, positive and negative predictive values] in detecting clinical disease)
 
According to a large reference laboratory, the identification of a characteristic 4q35 deletion is more than 90% specific for the disease.  
 
There are reports of a correlation between the degree of the mutation of the D4Z4 locus and the age at onset of symptoms, age at loss of ambulation, and muscle strength as measured by quantitative isometric myometry. Some reports in the literature describe individuals with a large contraction of the D4Z4 locus having earlier-onset disease and more rapid progression than those with smaller contractions of the D4Z4 locus, although other reports have not been able to confirm a correlation between disease severity and degree of D4Z4 contraction mutations (Lemmers, 1993).
 
On average, de novo mutations are associated with larger contractions of D4Z4 compared to the degree of D4Z4 contraction mutations observed segregating in families, and individuals with de novo mutations tend to have findings at the more severe end of the phenotypic spectrum (Lemmers, 1993).  
 
Clinical utility (how the results of the diagnostic test will be used to change management of the patient and whether these changes in management lead to clinically important improvements in health outcomes)
 
Individual
The clinical utility for patients with suspected FSHD depends on the ability of genetic testing to make a definitive diagnosis and for that diagnosis to lead to management changes that improve outcomes. There is no direct evidence for the clinical utility of genetic testing in these patients as no studies were identified that described how a molecular diagnosis of FSHD changed patient management.
 
However, for patients who are diagnosed with FSHD by identifying a D4Z4 contraction mutation, the clinical utility of molecular genetic testing for FSHD includes:
 
o Establishing the diagnosis and initiating/directing treatment, such as evaluation for physical therapy and the need for assistive devices, assessment for hearing loss, ophthalmologic examination for the presence of retinal telangiectasias and continued ophthalmologic surveillance, and possible orthopedic intervention.
 
o Distinguishing from other disorders that are similar clinically to FSHD, especially the limb-girdle muscular dystrophies and scapuloperoneal muscular dystrophy syndromes,
 
o Avoidance of a muscle biopsy in the majority of cases.
 
Treatment after a confirmed diagnosis of FSHD includes physical therapy and rehabilitation, exercise, pain management, ventilator support for those with hypoventilation, therapy for hearing loss, orthopedic intervention (ankle/foot orthoses; surgical fixation of the scapula to the chest wall to improve range of motion) and ophthalmologic management including lubricants or taping the eyes shut at night for exposure keratitis.
 
For those with a confirmed diagnosis of FSHD, the following surveillance applies (Lemmers, 1993) (Tawil, 2010):
 
· Regular assessment of pain
 
· Routine screening for hypoventilation in those with moderate to severe disease, and yearly forced vital capacity (FVC) measurements for all affected individuals who are wheel chair bound, have pelvic girdle weakness and superimposed pulmonary disease, and/or have moderate to severe kyphoscoliosis, lumber hyperlordosis, or chest wall deformities.
 
· Hearing loss assessment in children as routinely performed as part of school-based testing. In severe infantile onset forms of FSHD, hearing screens are important as hearing loss can result in delayed language acquisition. Adults should have a formal hearing evaluation based on symptoms.
 
· Annual dilated ophthalmoscopy in childhood is indicated. In adults, a dilated retinal exam should be performed at the time of diagnosis, and if vascular disease is absent, follow-up exams are only necessary if visual symptoms develop.
  
Family members
Most individuals diagnosed with FSHD have a parent with clinical findings of FSHD and one D4Z4 allele with a contraction mutation (70-90% of individuals with FSHD), although 10-30% of probands with FSHD have the disorder as a result of a D4Z4 de novo contraction mutation (Lemmers, 1993). Evaluation of at risk relatives may determine that they may be affected but escaped previous diagnosis because of a milder phenotypic presentation. However, for this population, no evidence was identified that compared outcomes in family members tested for genetic mutations compared to family members not tested for genetic mutations, and conclusions cannot be made on whether genetic testing of asymptomatic family members of a patient with known FSHD improves outcomes.
 
Summary
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease that typically presents before the age of 20 years with weakness of the facial muscles and the scapular stabilizer muscles; however, atypical presentations occur. The clinical course is usually of slowly progressive weakness, although the severity is highly variable. Approximately 95% of individuals with FSHD have contraction mutation of the D4Z4 locus. For the 5% of individuals with FSHD who do not have a contraction mutation of the D4Z4 locus, mutations in the gene SMCHD1 have been associated with FSHD.
  
The clinical utility of genetic testing for FSHD is that it leads to a definitive diagnosis, and can distinguish FSHD from other myopathies, with possible avoidance of a muscle biopsy. Changes in clinical management include supportive management involving physical therapy and rehabilitation, exercise, pain control and orthopedic interventions. Other potential benefits include increased surveillance for potential pulmonary, ophthalmologic and auditory problems related to FSHD. Therefore, genetic testing for FSHD may be considered medically necessary when a presumptive diagnosis of FSHD has been made based on clinical signs. Genetic testing for facioscapulohumeral muscular dystrophy is considered investigational for all other indications.
 
Practice Guidelines and Position Statements
In a report from the 171st European Neuromuscular Centre Internati0onal Workshop Standards of Care and Management of FSHD held in January 2010, it is stated that when a physician concludes facioscapulohumeral syndrome based on clinical findings, the odds are in favor of FSHD and genetic testing is the preferred diagnostic choice (Tawil, 2010).
 
Regulatory Status
No U.S. Food and Drug Administration (FDA)-cleared genotyping tests were found. Thus, genotyping is offered as a laboratory-developed test. Clinical laboratories may develop and validate tests in-house (“home-brew”) and market them as a laboratory service; such tests must meet the general regulatory standards of the Clinical Laboratory Improvement Act (CLIA).
 
2014 Update
 
A literature search conducted through July 2014 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Analytic Validity
No studies that assessed the analytic validity of SMCHD1 gene testing were identified.
 
Clinical Validity
(diagnostic performance of the test [sensitivity, specificity, positive and negative predictive values] in detecting clinical disease)
 
According to a large reference laboratory, the identification of a characteristic 4q35 deletion is more than 90% specific for the disease.  However, several studies have identified patients with no clinical signs of FSHD who have characteristic D4Z4 contractures, which has prompted the hypothesis that FSHD occurs only when the D4Z4 contracture occurs in a characteristic “permissive” background (Ricci, 2013).
 
No studies that assessed clinical validity of SMCHD1 gene testing were identified.
 
Clinical utility
 
Testing in individuals with suspected FSHD. The clinical utility for patients with suspected FSHD depends on the ability of genetic testing to make a definitive diagnosis and for that diagnosis to lead to management changes that improve outcomes.
 
Several studies suggest that the size of the D4Z4 repeat contraction is associated with differences in patients’ outcomes. Lutz et al conducted a retrospective analysis of 59 patients with FSHD seen at a single institution to evaluate the relationship between the D4Z4 repeat size and progression of hearing loss (Lutz, 2013). Eleven of the 59 patients evaluated had hearing loss that was not attributable to another cause. Truncated D4Z4 (1-10 D4Z4 repeats) was evaluated by the size of EcoRI or EcoRI/BlnI fragment, with an EcoRI fragment of less than 38 kB or an EcoRI/BlnI fragment of less than 35 kg corresponding to 1-10 D4Z4 repeats. There was a statistically significant negative association between hearing loss and fragment size in a simple logistic regression model (P = 0.0207). Six of the 11 patients with hearing loss had a history of hearing loss progression.
 
In a retrospective analysis of a cohort of patients with FSHD1 enrolled in the National Registry of FSHD Patients and Family Members, Statland et al evaluated the association between patient characteristics, including size of the D4Z4 contraction, and FSHD-related outcomes (Statland, 2014). Three hundred thirteen clinically affected participants with D4Z4 contractions of less than or equal to 38 kB were included. Those with D4Z4 contractions of less than or equal to 18 kg started using wheelchairs earlier than those with contractions from 19 to 28 kb (24.1 years vs 48.1 years, P<0.001) or those with contractions of greater than 38 kb (58.6 years, P<0.001).
 
Testing of family members with individuals with FSHD.
 
In 2013, Ricci et al evaluated the D4Z4 site in 367 relatives of 163 FSHD index cases who carried D4Z4 “alleles of reduced size” of less than or equal to 8 repeating units (Ricci, 2013). Among relatives, a D4Z4 “alleles of reduced size” with 1-3 repeating units and 4-6 repeating units was identified in 42 and 133 subjects, respectively. Of those relatives with 1-3 repeating units, about 40% demonstrated severe muscle symptoms by age 30, while none of those with 4 or more repeating units had severe symptoms in that age range.
 
In contrast to patients with diagnosed FSHD, there are no established treatment guidelines or follow-up guidelines for at-risk relatives.
 
D4Z4 contractions are associated with FSHD, and the size of the contracture is associated with more severe symptoms. Although there is no direct evidence for the clinical utility of genetic testing for patients with suspected FSHD, as no studies were identified that described how a molecular diagnosis of FSHD changed patient management, a chain of evidence supports the use of D4Z4 contraction mutation testing for suspected FSHD to establish a diagnosis and initiate therapies consistent with appropriate guidelines and avoid a muscle biopsy in the majority of cases.
 
Ongoing Clinical Trials: A search of the online site ClinicalTrials.gov in June 2014 found several ongoing trials related to genetic testing for FSHD:
 
  • A Multicenter Collaborative Study on the Clinical Features, Expression Profiling, and Quality of Life of Infantile Onset Facioscapulohumeral Muscular Dystrophy (FSHD) (NCT01437345) – This is an observational cohort study to evaluate muscle function, clinical phenotypes, possible genetic modifiers, and quality of life measures in patients with infantile onset and genetically confirmed FSHD. Enrollment is planned for 60 subjects; the estimated study completion date is March 2015.
  • Clinical, Genetic and Epigenetic Characterization of Patients with FSHD Type 1 and FSHD Type 2 (NCT01970735) – This study aims to compare the severity of illness in patients with FSHD1 and FSFHD2 in adults with clinical FSHD with or without genetic confirmation. Enrollment is planned for 100 subjects; the estimated study completion date is October 2016.
  
2015 Update
A literature search conducted through July 2015 did not reveal any new information that would prompt a change in the coverage statement.  
 
2017 Update
A literature search conducted through July 2017 did not reveal any new information that would prompt a change in the coverage statement.
 
2018 Update
A literature search was conducted through July 2018.  There was no new information identified that would prompt a change in the coverage statement.  

CPT/HCPCS:
81404MOLECULAR PATHOLOGY PROCEDURE LEVEL 5

References: Hassan A, Jones LK, Jr., Milone M et al.(2012) Focal and other unusual presentations of facioscapulohumeral muscular dystrophy. Muscle Nerve 2012; 46(3):421-5.

Lemmers R, Miller DG, van der Maarel SM.(1993) Facioscapulohumeral Muscular Dystrophy. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong CT, Stephens K, eds. GeneReviews. Seattle (WA)1993.

Lemmers RJ, Miller DG, van der Maarel SM.(2014) Facioscapulohumeral Muscular Dystrophy. GeneReviews 2014; http://www.ncbi.nlm.nih.gov/books/NBK1443/. Accessed July, 2014.

Lemmers RJ, O'Shea S, Padberg GW, et al.(2012) Best practice guidelines on genetic diagnostics of Facioscapulohumeral muscular dystrophy: workshop 9th June 2010, LUMC, Leiden, The Netherlands. Neuromuscul Disord. May 2012(a);22(5):463-470. PMID 22177830

Lemmers RJ, Tawil R, Petek LM, et al.(2012) Digenic inheritance of an SMCHD1 mutation and an FSHD-permissive D4Z4 allele causes facioscapulohumeral muscular dystrophy type 2. Nat Genet. Dec 2012(b);44(12):1370-1374. PMID 23143600

Lemmers RJLF, Miller DG, van der Maarel SM.(2014) Facioscapulohumeral Muscular Dystrophy. In: Adam MP, Ardinger HH, Pagon RA, et al., eds. GeneReviews. Seattle, WA: University of Washington; 2014.

Lutz KL, Holte L, Kliethermes SA, et al.(2013) Clinical and genetic features of hearing loss in facioscapulohumeral muscular dystrophy. Neurology. Oct 15 2013;81(16):1374-1377014. PMID 24042093

Menezes MP, North KN.(2012) Inherited neuromuscular disorders: pathway to diagnosis. J Paediatr Child Health 2012; 48(6):458-65.

Pastorello E, Cao M, Trevisan CP.(2012) Atypical onset in a series of 122 cases with FacioScapuloHumeral Muscular Dystrophy. Clin Neurol Neurosurg 2012; 114(3):230-4.

Ricci G, Scionti I, Sera F, et al.(2013) Large scale genotype-phenotype analyses indicate that novel prognostic tools are required for families with facioscapulohumeral muscular dystrophy. Brain. Nov 2013;136(Pt 11):3408-3417. PMID 24030947

Sacconi S, Lemmers RJ, Balog J, et al.(2013) The FSHD2 gene SMCHD1 is a modifier of disease severity in families affected by FSHD1. Am J Hum Genet. Oct 3 2013;93(4):744-751. PMID 24075187

Statland JM, Tawil R.(2014) Risk of functional impairment in Facioscapulohumeral muscular dystrophy. Muscle Nerve. Apr 2014;49(4):520-527. PMID 23873337

Tawil R, van der Maarel S, Padberg GW et al.(2010) 171st ENMC international workshop: Standards of care and management of facioscapulohumeral muscular dystrophy. Neuromuscul Disord 2010; 20(7):471-5.

University of Iowa Diagnostic Laboratories.(2013) Facioscapulohumeral Dystrophy (FSHD) Information. http://www.healthcare.uiowa.edu/path_handbook/Appendix/Outreach/fshd.html. Last accessed July 2013.

van der Maarel SM, Tawil R, Tapscott SJ.(2011) Facioscapulohumeral muscular dystrophy and DUX4: breaking the silence. Trends Mol Med 2011; 17(5):252-8.


Group specific policy will supersede this policy when applicable. This policy does not apply to the Wal-Mart Associates Group Health Plan participants or to the Tyson Group Health Plan participants.
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