• Test Code:
    2026
  • Department:
  • Test Synonyms:
    CPEOKearns-Sayre Syndrome (KSS)Pearson SyndromePLOG-Related Disorders
  • CPT Code(s):
    81479
Background:

Mitochondrial deletion syndromes are generally organized into the following three major overlapping phenotypes:

  • PEO - progressive external ophthalmoplegia is a condition characterized by weakness of the eye muscles.  The condition typically appears in adults between ages 18 and 40.  The most common signs and symptoms of progressive external ophthalmoplegia are drooping eyelids (ptosis), which can affect one or both eyelids, and weakness or paralysis of the muscles that move the eye (ophthalmoplegia).  Affected individuals may also have general weakness of the skeletal muscles (myopathy), particularly in the neck, arms, or legs.
  • KSS - Progressive external ophthalmoplegia is part of a spectrum of disorders with overlapping signs and symptoms.  Similar disorders include other conditions caused by POLG gene mutations, such as ataxia neuropathy spectrum, as well as other mtDNA deletion disorders, such as Kearns-Sayre syndrome.  Like progressive external ophthalmoplegia, the other conditions in this spectrum can involve weakness of the eye muscles.  However, these conditions have many additional features not shared by most people with progressive external ophthalmoplegia.
  • Pearson Syndrome – Pearson syndrome is a mitochondrial disease characterized by sideroblastic anemia and exocrine pancreas dysfunction.  It is usually fatal in infancy.  Those who survive into adulthood often develop symptoms of Kearns-Sayre syndrome.

Reason for Referral:
Confirmation of diagnosis of patient having symptoms of a mitochondrialopathy disorder.

Methodology:

Genomic DNA is used for copy number analysis of the whole mitochondrial genome using a custom-designed oligonucleotide mitochondrial DNA-based array using probes distributed across the entire mitochondrial genome.

Specimen Requirements:

  • Muscle: 100 mg muscle recommended for CPEO and Kearns-Sayre syndrome
  • Blood: 6.0 mL EDTA (purple-top) or ACD (yellow-top) tube for Pearson syndrome
  • DNA: 10µg at a minimum of 100ng/µL
A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES.  Please include detailed clinical information,  including ethnicity, clinical history, and family history.

Test Performed (Days):

Weekly

Turn Around Time:

14 – 21 Days

Shipment Sensitivity Requirements:

  • Package and ship specimen to remain cold, but not frozen. 
  • Ship via overnight express, using the FedEx priority overnight label provided. 
  • Contact Client Services for shipping kits and instructions at (855) 535-1522(855) 535-1522.

References:

  1. Cohen, BH et al. POLG-Related Disorders. GeneReviews [Internet]. http://www.ncbi.nlm.nih.gov/books/NBK26471/

Additional Info:

Confirmation of diagnosis of patient having symptoms of a mitochondrialopathy disorder.  

  • The resulting absence or presence of a deletion may be a reflection the sample type submitted, i.e.,  mitochondrial deletions may not always be detectable in blood.
  • While major rearrangements of mtDNA are usually sporadic, rearrangements may be inherited in some cases.  Family studies may therefore be warranted.

The Knight Cancer Institute at Oregon Health & Science University is a pioneer in the field of precision cancer medicine. The institute's director, Brian Druker, M.D., helped prove it was possible to shut down just the cells that enable cancer to grow. This breakthrough has made once-fatal forms of the disease manageable and transformed how cancer is treated. The OHSU Knight Cancer Institute is the only National Cancer Institute-designated Cancer Center between Sacramento and Seattle – an honor earned only by the nation's top cancer centers. It is headquarters for one of the National Cancer Institute's largest research collaboratives, SWOG, in addition to offering the latest treatments and technologies as well as hundreds of research studies and clinical trials.

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