For families with these mutations, genetic anticipation—in which the signs and symptoms of the genetic disorder become more severe or appear at an earlier age as the disorder is passed from one generation to the next—leads to a unique pattern of inheritance where disease manifestation can change in each generation. “This moving target can make catching a telomerase mutation difficult clinically,” said Dr. Alder.
He said that flow cytometry fluorescent in-situ hybridization (FlowFISH), a technique that uses a combination of flow cytometry with cytogenetic fluorescent in-situ hybridization staining protocols to quantify the copy number of specific repetitive elements in genomic DNA of whole cell populations, can be used to distinguish mutation carriers from non-carriers and to identify people who potentially carry short telomeres.
What can be gleaned from data of families with these genetic syndromes with mutant telomere genes is that telomerase mutations cause stem cell failure in highly proliferative tissues, but more frequently affect slow turnover tissues, such as the lung.
More research is needed to understand the clinical significance of this association between telomere shortening and immune response, with a number of questions remaining to be answered. Among these is a need to better understand the functional consequence of telomere shortening due to chronic inflammation and aging, according to Dr. Alder.
As more evidence emerges and the association between telomere shortening and immune function is better understood, new approaches to treating various immune disorders may develop.
“New therapies might stop this shortening in order to normalize immune function in chronic inflammatory diseases, as well as in normal aging,” said Dr. Sigal.
Mary Beth Nierengarten is a freelance medical journalist based in St. Paul, Minn.