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Basal Ganglia Calcification Dystonia (NGS Panel and Copy Number Analysis)

CPT: 81405 (x3), 81406, 81479

Genes Assessed


      Specimen Requirements


      Specimen

      Whole blood, oral swab, extracted DNA (from blood or oral swab only)


      Volume

      Whole blood: 4 ml
      Oral swab: 3 swabs
      Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST) 


      Minimum Volume

      Whole blood: 2 ml
      Oral swab: 1 swab
      Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST)


      Container

      Whole blood: Lavender-top (EDTA) 
      Oral swab: OCD-100 DNA Genotek
      Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST)


      Collection

      Whole blood: standard phlebotomy. 
      Oral swab: follow kit instructions
      Extracted DNA: Contact MNG Genetic Services 844-664-8378 (844-MNGTEST)


      Storage Instructions

      Maintain specimen at room temperature or refrigerate at 4°C. Do not freeze. 


      Stability Requirements

      • Room temperature: Whole blood: 14 days; Swab: 60 days
      • Refrigerated: Whole blood: 30 days; Swab: 60 days
      • Frozen: Do not freeze


      Causes for Rejection

      Frozen or hemolyzed specimen; quantity not sufficient for analysis; improper container


      Test Details


      Use

      Familial idiopathic basal ganglia calcification (FIBGC, formerly known as Fahr disease) is a condition characterized by abnormal deposits of calcium (calcification) in the brain. These calcium deposits typically occur in the basal ganglia, which are structures deep within the brain that help start and control movement; however, other brain regions can also be affected. The signs and symptoms of FIBGC include movement disorders and psychiatric or behavioral difficulties. These problems begin in adulthood, usually in a person's thirties. The movement difficulties experienced by people with FIBGC include involuntary tensing of various muscles (dystonia), problems coordinating movements (ataxia), and uncontrollable movements of the limbs (choreoathetosis). Affected individuals often have seizures as well. The psychiatric and behavioral problems include difficulty concentrating, memory loss, changes in personality, a distorted view of reality (psychosis), and decline in intellectual function (dementia). An estimated 20 to 30 percent of people with FIBGC have one of these psychiatric disorders.


      Limitations

      This assay will not consistently detect mosaicism or rule out the presence of large chromosomal aberrations, including rearrangements and inversions that do not change copy number of genomic regions. This NGS assay does not detect repeat expansions. False positive or false negative results may occur for reasons that include insufficient information available about rare genetic variants, sex chromosome abnormalities, pseudogene interference, homologous regions, blood transfusions, bone marrow transplantation, somatic or tissue-specific mosaicism/heteroplasmy, mislabeled samples, or erroneous representation of family relationships. For panels with mitochondrial DNA assessment, low levels of heteroplasmy may not be reliably detected. Interpretation of the clinical significance of gene variations is limited by information about the variant that is available at the time of reporting, and by the quality and quantity of clinical information provided with the sample. The interpretation of the clinical significance of variants may change.

      This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.


      Methodology

      Next-generation sequencing to identify genetic variants, including single nucleotide variants (SNVs), insertions, deletions, and copy number variants (CNVs). 


      Recommended MNG Kits

      SINGLE Blood Genetic Testing, Buccal Swab Genetic Testing