POLG1-related Disorders - Sequencing
|Disorders||Alpers-Huttenlocher syndrome (AHS)
Childhood Myocerebrohepatopathy Spectrum (MCHS)
Myoclonic Epilepsy Myopathy Sensory Ataxia (MEMSA)
Ataxia Neuropathy Spectrum (ANS)
Autosomal Recessive Progressive External Ophthalmoplegia (arPEO)
Autosomal Dominant Progressive External Ophthalmoplegia (adPEO)
|Clinical info||POLG1 mutations are responsible for multiple clinical diagnoses with overlapping phenotypes. Aside from Autosomal Dominant Progressive External Ophthalmoplegia, all of the other conditions are inherited in an autosomal recessive manner.
Alpers-Huttenlocher syndrome (AHS) includes a progressive and severe encephalopathy with epilepsy, neuropathy and liver failure.
Childhood Myocerebrohepatopathy Spectrum (MCHS) presents before age three with developmental delay, lactic acidosis, failure to thrive and myopathy. Hearing loss, cyclic vomiting, renal and hepatic problems are also often present.
Myoclonic Epilepsy Myopathy Sensory Ataxia (MEMSA) includes myopathy, epilepsy and ataxia without ophthalmoplegia and generally presents in young adulthood.
Ataxia Neuropathy Spectrum (ANS) includes mitochondrial recessive ataxia syndrome (MIRAS) and sensory ataxia neuropathy dysarthria and ophthalmoplegia (SANDO). Features include ataxia, neuropathy and often encephalopathy with seizures.
Autosomal Recessive Progressive External Ophthalmoplegia (arPEO) involves progressive PEO without systemic involvement.
Autosomal Dominant Progressive External Ophthalmoplegia (adPEO) involves progressive weakness of the extraocular eye muscles which causes strabismus and ptosis.
|Indications||Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutation(s) within a family to allow for carrier testing and prenatal diagnosis.|
|Detection||Sequencing of the gene will detect mutations approximately 95% of individuals with a POLG1-related disorder.|
|Specimen Requirements||5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 ml|
|Transport||The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.|
|Turnaround time||21 days|
|Prenatal testing||Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.|
|CPT Codes||Unknown mutation
|Cost||$2000 for sequencing
$350 for known mutation
Molecular Diagnostic Lab
The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.