Telomeres and Telomerase Deficiency

Telomere disorders are caused by extremely short telomeres. When telomeres become extremely short, cells can no longer divide effectively. An inherited mutation in the gene that produces the telomere lengthening enzyme called telomerase disables the enzyme and causes telomeres to shorten at a faster rate.

RepeatDx’s procedure has been shown to be a valuable screening test for inherited telomere maintenance deficiencies. Several recent peer-reviewed scientific publications show that telomere length analysis with Flow FISH can be used to identify individuals with various forms of inherited telomerase deficiency and carriers of mutations in telomerase genes or in genes encoding telomere binding proteins. More information on RepeatDx and our Flow FISH technology can be found in the FAQ section.

Inherited deficiencies where telomere measurements are used in diagnosis include bone marrow failure, dyskeratosis congenita, immune deficiencies and pulmonary fibrosis.

Dyskeratosis Congenita

Dyskeratosis Congenita (DC) is an inherited bone marrow failure syndrome that develops as a result of defective telomere maintenance, it is therefore categorized as a telomere biology disorder (TBD). The clinical sensitivity and specificity for Flow FISH telomere length analysis have been defined for the diagnosis of DC.

  • DC can affect every organ system, and symptoms can vary from person to person. Symptoms may be present at birth, appear in infancy, childhood or adulthood. Telomere length analysis allows for early identification of individuals who may not yet have manifested disease features.
  • TBDs are associated with Low (L) or Very Low (VL) leukocyte telomere length – DC is associated with VL – in several leukocyte subsets and in the presence of specific symptoms and/or significant family history.
  • The introduction of telomere length diagnostic testing and genetic testing have revealed a growing clinical spectrum of DC-associated TBDs. These include the severe inherited syndromes: Hoyeraal Hreidarsson (HH) syndrome, Revesz syndrome and Coats plus syndrome.
  • Research reports published in the scientific and medical literature point to other potentially clinically valuable applications of telomere length testing, however, critical values have not yet been formally established.

A guideline for the diagnosis and management of Dyskeratosis Congenita and Telomere Biology Disorders, edited by Drs. Sharon A. Savage and Elizabeth F.Cook, can be found on the Team Telomere website.

Pulmonary Fibrosis

Pulmonary fibrosis (PF) has been linked to abnormal telomere maintenance. Studies have found that Very Low (VL) leukocyte telomere length is independently associated with worse survival for PF patients. Reasons for testing include:

  • Diagnostic tool for individuals with familial and idiopathic PF.
  • Telomere length is associated with transplant free survival and can aid in disease course prediction and treatment planning.
  • Risk assessment for lung transplantation as well as post-transplant immunosuppression guidance.
  • In high risk patients, who may be unable to undergo lung biopsies, telomere length analysis can provide critical information.
  • Cost of a Flow FISH telomere test is less than genetic testing and has a faster turn around time.

Bone Marrow Donors Screening

Findings have indicated that telomere length shortens rapidly in patients immediately following hematopoietic stem cell transplantation.

  • It is important to identify donors with healthy telomere maintenance that are within the biologically tolerable range of the recipient.
  • If hematopoietic stem cells from older telomere maintenance deficient donors are transplanted into younger patients, the telomeres may become too short resulting in cellular senescence and bone marrow failure.

Coronary artery disease

Telomere shortening plays a crucial role in the pathogenesis of aging-associated coronary artery disease (CAD).

  • Short telomeres can lead to cellular senescence and apoptosis, which contribute to the development of atherosclerosis and predispose people to plaque instability.
  • Both genetic and environmental factors have been associated with individual variations in telomere length.
  • Cardiovascular risk factors such as smoking, diabetes mellitus, hypertension, obesity, sedentary lifestyle, and stress have been considered to increase oxidative stress or inflammation, consequently accelerating telomere shortening.

Other

RepeatDx provides telomere testing for individuals who, under physician supervision, may be interested in telomere length measurements as a biomarker for monitoring disease or family history risks.

Due to regulator requirements, RepeatDx cannot provide diagnostic testing direct to consumers. Before acquiring a blood sample, the requisition form must be reviewed and signed by a practicing licensed physician. RepeatDx does not recommend or approve treatments designed to optimize telomere modifications.

For patients and families wanting more information on telomere biology disorders, visit the Team Telomere website.