Why order a telomere test?

With research and clinical applications for telomere length measurements increasing we discuss some situations when it may be helpful for physicians or researchers to order a telomere test.

There are many situations in which telomere length measurements can be helpful, both in clinical care and in research settings. For the former, telomere test results can provide physicians with laboratory findings to support diagnosis and treatment planning for patients with a range of conditions. For the latter, investigating associations between telomere length and a spectrum of conditions can provide new information on disease course prediction and improve tailored treatment options.

We know there are many applications for telomere length testing with a large scope of different goals.

Three examples when it may be particularly helpful for physicians to order a telomere test:

• A patient presents with dyskeratosis congenita (DC) symptoms

DC is a telomere biology disorder (TBD) with a wide range of possible presenting symptoms and age of onset. However, there are three classic DC symptoms including abnormal skin coloration (in a lace pattern), nail dystrophy and white patches in the mouth (oral leukoplakia). If a patient presents with a combination of these together with abnormally low blood counts, a physician may order a telomere test to aid diagnosis of this rare disease. The Dyskeratosis Congenita and Telomere Biology Disorders: Diagnosis and Management Guidelines provide a recommendation to use Flow FISH telomere testing for TBD diagnosis purposes.

Importantly, there are also individuals who have later onset forms of TBD, whose symptoms may remain mild and sub-clinical for longer. They may only present with TBD related disease (e.g. pulmonary fibrosis or bone marrow failure) as older adults. Therefore, testing may also be considered with suspected TBD when there is a suggestive family history, even in the absence of classic DC symptoms.

• A family history of pulmonary fibrosis (PF) is known or discovered

Many cases of PF are defined as idiopathic pulmonary fibrosis (IPF) as there is no known cause for the onset of the condition. However, in a significant proportion of these cases there may be an underlying inherited cause. When a patient has relatives, who have also been diagnosed with PF, or related conditions (for example a TBD like DC), a telomere length test may help to define the underlying inherited nature of the disease.

Being able to identify IPF as familial enables patients and their relatives to have a formal diagnosis for their health condition. In turn, this can enable care teams to recommend preventative behaviors, proactive screening and regular monitoring for optimal health of these individuals.

• Planning for a related donor stem cell transplant for a patient with a hereditary disease

For patients with TBDs and bone marrow failure or aplastic anemia, a stem cell transplant can be a life-saving treatment option. Transplanting healthy stem cells allows the bone marrow to produce fully-functional blood cells.

When planning such a transplant, however, it is crucial for patients with inherited conditions that appropriate screening of their related donor is conducted. For example, it would be important to confirm that the donor had telomeres within a normal range ensuring the stem cells donated are optimal to correct the deficiency. For a more in-depth exploration of testing prior to transplant, read this dedicated blog.

For more information on how to order a telomere test, including downloading the requisition form, visit our website.

To read more about the applications of telomere testing follow this link.

Sources

Ballew, B. & Savage, S. Updates on the biology and management of dyskeratosis congenita and related telomere biology disorders. Expert Review of Hematology. 2013. 6:3, 327-337. doi: 10.1586/ehm.13.23.

Savage, S. & Cook, E. Dyskeratosis Congenita and Telomere Biology Disorders: Diagnosis and Management Guidelines. (First ed.) 2015. Accessed at: https://teamtelomere.org/wp-content/uploads/2018/07/DC-TBD-Diagnosis-And-Management-Guidelines.pdf