GeneDx believes in responsible testing that is based on established medical guidelines, and we aim to be completely transparent with our pricing so that patients, clinicians, and payers know the cost of the test.
Molecular confirmation of a clinical diagnosis
To assist with decisions about treatment and management of individuals with nystagmus
Testing of at-risk relatives for specific known variant(s) previously identified in an affected family member
Prenatal diagnosis for known familial pathogenic variant(s) in at-risk pregnancies
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Oliveira et al. (2005) Dev Med Child Neurol 47 (3):185-9 (PMID: 15739723)
Chinnery P. Mitochondrial Disorders Overview 2000 Jun 8 [Updated 2014 Aug 14]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2018. Available from: https://www.ncbi.nlm.n
van Adel et al. (2009) Journal Of Clinical Neuromuscular Disease 10 (3):97-121 (PMID: 19258857)
Zhu et al. (2009) Acta Biochim. Biophys. Sin. (Shanghai) 41 (3):179-87 (PMID: 19280056)
Fratter et al. (2011) Neurology 76 (23):2032-4 (PMID: 21646632)
Milone et al. (2010) Neurologist 16 (2):84-91 (PMID: 20220442)
Stewart et al. (2008) Neurology 71 (22):1829-31 (PMID: 19029523)
Spiegel et al. (2012) American Journal Of Human Genetics 90 (3):518-23 (PMID: 22405087)
Pilz et al. (2017) J Optom 10 (4):205-214 (PMID: 28040497)
Testing of patients suspected of having a mitochondrial disorder
65 confirmed disease-causing mtDNA point variants (see list in Test Info Sheet) and large scale deletion analysis of the mitochondrial genome (including LHON [20 mutations], MELAS [16 mutations], LS/NARP [22 mutations], MIHL/MIDM [10 mutations)] MERRF [6 mutations], KSS, CPEO, Pearson syndrome, etc.)
Tissue Biopsy (>50 mg Muscle or Liver-Flash Frozen)
2-5 mL Blood - Lavender Top Tube|Oral Rinse (30-40 mL)
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Thorburn, D. Gene Reviews (2006) Mitochondrial DNA-Associated Leigh Syndrome and NARP.
DiMauro, S. Gene Reviews (2005) MELAS.
Yu-Wai-Man, P and Chinnery, P. Gene Reviews (2008) Leber Hereditary Optic Neuropathy.
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Differential diagnosis: Dietary vitamin A deficiency, vitamin A deficiency resulting from a lack of lipoprotein (Bassen-Kornzweig syndrome), a lack of serum retinoid-binding protein, gyrate atrophy or choroideremia.
Carrier testing for family members of an affected individual with known mutation(s).
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Ophthalmology Variant Testing Program (VTP)
Laboratories classify genetic changes as variants of uncertain significance (VUS) if there is incomplete or conflicting information about the health consequences of the variant. In some cases, testing family members for the presence or absence of the VUS may contribute to a better understanding of the variant and may be one piece of evidence leading to eventual reclassification of a VUS as a pathogenic, likely pathogenic, benign, or likely benign variant. For such cases, GeneDx has established a Variant Testing Program (VTP).
How do I determine if a variant is eligible for the Ophthalmology VTP?
GeneDx considers requests for the Ophthalmology VTP for any individual found to have a VUS identified by a GeneDx Ophthalmology panel or single gene test. These studies will be performed at no additional charge for select and pre-approved family members who meet certain criteria and for whom appropriate clinical information is provided. Please note that GeneDx requires specific clinical documentation to ensure the most informative family members are tested. GeneDx will make the final determinations for VTP in its sole discretion.
GeneDx will test up to two affected family members at no charge through the Ophthalmology VTP. If the family history is completely negative, then testing of both parents is available at no additional charge to determine if the variant has occurred de novo.
Application process for the Ophthalmology VTP:
Please fax a detailed pedigree and any relevant clinical information/evaluations to the GeneDx Ophthalmology genetic counselors at 301-519-2892, email firstname.lastname@example.org, or call 301-519-2100 and ask to speak with a genetic counselor. Please be sure to indicate that you are submitting the information for VTP consideration, and include the name and/or GeneDx accession number of the proband.
Our team will review the case and will determine if there are informative family members appropriate for evaluation through the VTP. Cases are typically reviewed within a few days, but please allow up to 3 weeks after receipt of the application for a reply.
Please note that in order to qualify for the Ophthalmology VTP, we require detailed clinical records and may require documentation of specific studies, such as a comprehensive evaluation by an ophthalmologist or an electroretinogram (ERG), even on at-risk family members who are clinically asymptomatic. Because the clinical information is being used to assess segregation of a variant with disease in the family, detailed clinical records and the submission of a pedigree or family history information are required.
A member of our team will contact the ordering provider or genetic counselor after the case has been reviewed to let him/her know if the family has been accepted in the VTP. If we are extending an offer for family member variant testing at no additional charge, we will discuss logistics of sample submission at that time.
Reasons why a family might not be accepted into the Ophthalmology VTP:
There are no informative family members available for testing.
The variant is present with an allele frequency that is higher than expected for a pathogenic variant based on the prevalence of the disease in the population and on genetic heterogeneity, so familial segregation studies will not be informative.
The variant is in a gene that does not correspond to the disease phenotype in the family.
In certain circumstances, it may be more informative to perform more comprehensive diagnostic genetic testing in affected family member(s) instead of targeted testing of one or more unaffected relatives for a VUS.
Variant studies for the evaluation of a single VUS in a gene associated with an autosomal recessive disorder are rarely informative. Therefore, these requests are typically denied.
Revising the classification of variants of uncertain significance takes a great deal of data and information from multiple sources. Therefore, there is no guarantee that participation in the Variant Testing Program will lead to an updated classification of a VUS based on information from a single family, although cumulative data collected from multiple families over time may lead to a more definitive classification for a variant.
For more information please contact:
The GeneDx Genetic Counselors at 301-591-2100