Coverage Policy Manual - Arkansas Blue Cross and Blue Shield

Genetic Test: Canavan Disease

Description:

The term Canavan's disease is used to describe an autosomal recessive spongy degeneration of the brain, occurring mainly among Ashkenazi Jewish individuals, and characterized by increased levels of N-acetylaspartic acid (NAA) in the urine and plasma and aspartoacylase deficiencies in cultured skin fibroblasts. It is caused by a deficiency of aspartoacylase (ASPA), an enzyme playing a role in myelin synthesis. Elevated levels of NAA are found in urine, serum, and CSF. Canavan's disease results from mutations in the ASPA gene on chromosome 17p13. DNA analysis is the method of choice for prenatal diagnosis. When the molecular diagnostic tests are filed, the genetic modifier SA, found in Appendix I of the CPT coding manual, must be appended to the line item of the claim.

The three types of Canavan's disease are characterized by abnormal white matter signal on MRI and lack of involvement of peripheral nerves. Large amounts of NAA are found in urine. The infantile form, or classic Canavan's disease, begins within a few months of birth, and death generally occurs by 3 to 4 years of age. The infant initially is hypotonic and has poor head and neck control. Megalocephaly is common by 6 months of age, and arrested development is consistent. In the second 6 months, hypotonia is replaced by spasticity and often by decorticate and decerebrate posturing. Some hyper-reactivity is precipitated by auditory, visual, and tactile stimuli. Vision deteriorates as optic atrophy and nystagmus develop. Seizures of various types, including focal and myoclonic seizures, are usual, and choreoathetotic or dystonic movements can occur. Dysautonomia in the form of paroxysmal episodes of sweating, hyperthermia, vomiting, and hypotension are terminal manifestations.

The neonatal form of Canavan's disease is deadly within a few weeks and is characterized by lethargy, hypotonia, diminished spontaneous movement, and difficulty in swallowing. The rare juvenile form develops after 5 years of age and extends into adolescence. Ataxia, tremor, ptosis, and mental deterioration are characteristic. The course is characterized by progressive cerebellar symptoms, dysarthria, dementia, seizures, spasticity, and loss of vision. There is no correlation between the severity of the morphological white matter changes and the clinical presentation.

Coding

A Specific CPT code for this testing became available in 2012:

81200: ASPA (aspartoacylase) (e.g., Canavan disease) gene analysis, common variant (e.g., E285A, Y231X).

Policy/
Coverage:

Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria

Genetic testing for Canavan’s disease meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness to test the affected infant or child to determine if the neurological disease demonstrated by the affected child is Canavan’s disease. This would include testing of amniotic fluid.

Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria

Testing of the parent(s) or prospective parent(s) to determine if the parent(s) has the recessive gene for Canavan’s disease does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.

For members with contracts without primary coverage criteria, testing of the parent(s) or prospective parent(s) to determine if the parent(s) has the recessive gene for Canavan’s disease is considered investigational. Investigational services are specific contract exclusions in most member benefit certificates of coverage.

Rationale:

The American College of Obstetrics & Gynecology (ACOG committee opinion, screening for Canavan’s Disease, No, 212, November 1998, Committee on Genetics) and the American College of Medical Genetics (1998-01-10; <www.acmg.net/resources/policies/pol-003.asp>, accessed 2004-09-01) have the following recommendations:

“The screening test to identify individuals who are carriers is a DNA-based test that is performed by only a few specialized laboratories.
“If both reproductive partners have an Ashkenazi Jewish background, we recommend that carrier testing for Canavan Disease be offered before pregnancy. If only one partner is of Ashkenazi Jewish descent, she/he should be offered carrier testing and the couple should be counseled regarding the limitations and benefits of carrier testing and prenatal diagnosis for this situation.
"If a family member is affected, the proband's mutation(s) should be defined and the relatives should be offered screening for this mutation(s).

2008 Update

Review of peer reviewed medical literature through July 2008 provided no information which would change the above coverage policy.

2011 Update

A review of the literature has been conducted through December 2010. There was no new literature identified that would prompt a change in the coverage statement.

Clinical Utility:

The clinical utility of a direct diagnostic test for the detection of a mutation of the ASPA gene to establish a diagnosis of Canavan disease has been found to have little, if any, risks associated with it and the benefits of this test can be invaluable in selected cases.

New York State Validation Program:

Currently there is no evidence that testing for a mutation of the ASPA gene in Canavan disease has been validated by the New York State Validation program.

Clinical Appropriateness:

ASPA mutation genetic testing is deemed appropriate for patients in which a clinical diagnosis of Canavan disease is suspected, especially in Ashkenazi Jewish individuals.

EGAPP:

ASPA mutation testing has not been evaluated by EGAPP. It has not been identified as a topic of interest, and it is not currently on the list of tests to be evaluated in the future.

Gene Reviews:

Gene mutation testing has been evaluated by Gene Reviews and is recognized as a legitimate testing modality for confirmation of the diagnosis of Canavan disease. It is currently on the Gene Reviews website with a full explanation of the testing process and the current laboratories that perform these molecular diagnostic tests. Tests for only one gene mutation (ASPA) are known to be applicable and are available.

American College of Medical Genetics:

Gene mutation testing for the ASPA gene is not currently listed on the website for the American College of Medical Genetics.

BCBSA MPRM Policy:

BCBSA MPRM currently has no policy on ASPA gene mutation testing for Canavan disease.

Hayes Inc Assessment:

Hayes Inc Assessment states that gene mutation testing for Canavan disease has a B rating for the ASPA gene.

2013 Update

A literature search was conducted using the MEDLINE database through May 2013. There was no new information identified that would prompt a change in the coverage statement.

2015 Update

A literature search conducted using the MEDLINE database did not reveal any new literature that would prompt a change in the coverage statement.

2017 Update

A literature search performed using the MEDLINE database did not reveal any new information that would prompt a change in the coverage statement.

2018 Update

Annual policy review completed with a literature search using the MEDLINE database through May 2018. No new literature was identified that would prompt a change in the coverage statement.

2019 Update

Annual policy review completed with a literature search using the MEDLINE database through May 2019. No new literature was identified that would prompt a change in the coverage statement.

2020 Update

A literature search was conducted through May 2020. There was no new information identified that would prompt a change in the coverage statement.

2021 Update

Annual policy review completed with a literature search using the MEDLINE database through May 2021. No new literature was identified that would prompt a change in the coverage statement.

2022 Update

Annual policy review completed with a literature search using the MEDLINE database through May 2022. No new literature was identified that would prompt a change in the coverage statement.

2023 Update

Annual policy review completed with a literature search using the MEDLINE database through May 2023. No new literature was identified that would prompt a change in the coverage statement.

CPT/HCPCS:

References:

ACOG committee opinion, screening for Canavan’s Disease, No, 212. November 1998, Committee on Genetics.

American College Medical Genetics 1998-01-10; .

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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