Telomeres and Telomere Biology Disorders

Chromosomes have protective structures located at their ends called telomeres. These telomeres normally shorten as a person gets older. In some individuals the length is abnormally short or the shortening process is accelerated (in some cases both issues can occur). Telomere biology disorders are caused by extremely short telomeres. When telomeres become extremely short, cells can no longer divide effectively. These defects may be caused by inherited deficiencies in genes involved in telomere maintenance or telomere biology or by unknown stressors.

Telomeres in Diagnosis and Treatment

A telomere length analysis test is a blood test that measures the length of the telomeres, and the information collected can be used to confirm a diagnosis when a person has signs or symptoms that may be due to a telomere deficiency.

The RepeatDx® 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.

Inherited deficiencies where telomere analysis is used in clinical diagnosis and to guide treatment include bone marrow failure, dyskeratosis congenita, aplastic anemia, acute myeloid leukemia, immune deficiencies, and pulmonary fibrosis

There are important considerations when conducting testing as results could indicate a heritable condition that may have implications for families as well as the individual being tested. Genetic counseling can be a helpful way for individuals and their families to discuss and prepare for testing and test results. For more information read this guest blog from a genetic counselor examining some of the implications that come with telomere testing.


Findings have indicated that telomere length shortens rapidly in patients immediately following hematopoietic stem cell transplantation. Studies also indicate a strong relationship between donor pre-transplant telomere length and recipient post-transplant telomere length. Therefore, 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 donors with deficient telomere maintenance are transplanted into younger patients, the telomeres may become too short resulting in cellular senescence and bone marrow failure.


Gadalla S, M., Aubert G., Wang T., et al. Donor telomere length and causes of death after unrelated hematopoietic cell transplantation in patients with marrow failure. Blood. 2018;131(21):2393–2398. doi:10.1182/blood-2017-10-812735.

Newton C, A., Zhang D., Oldham J,M. et al. Telomere Length and Use of Immunosuppressive Medications in Idiopathic Pulmonary Fibrosis. Am J Respir Crit Care Med. 2019 Aug 1;200(3):336-347. doi: 10.1164/rccm.201809-1646OC.

Agrusa J, E., Bertuch A, A., DiNardo C, D. et al. Severe therapy-related toxicities after treatment for Hodgkin lymphoma due to a pathogenic TERT variant and shortened telomeres. Pediatr Blood Cancer. 2019 Aug;66(8):e27779. doi: 10.1002/pbc.27779.

Telomeres and research

Other medical conditions where telomere length investigations and ongoing research may benefit clinical care include chronic lymphocytic leukemia and cardiovascular diseases including coronary artery disease.

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 more information on research collaborations please contact us.