Telomeres protect the ends of chromosomes, shorten with age, and are very short in dyskeratosis congenita (DC), an inherited bone marrow failure syndrome (IBMFS) associated with mutations in telomere biology genes. “Short telomeres” were reported in Fanconi Anemia (FA), Diamond-Blackfan Anemia (DBA) and Shwachman-Diamond Syndrome (SDS) using telomere restriction fragment length or Q-FISH assays of total leukocyte or mononuclear cell DNA. These reports focused on group averages, not results from individual patients. Our objective was to determine which categories of IBMFS patients have very short telomeres, and in which leukocyte subsets, using a more sensitive and specific assay. Telomere length was measured in granulocytes, lymphocytes, naïve T-cells, memory T-cells, B-cells, and NK cells using automated multicolor flow fluorescence in situ hybridization (FISH). We previously showed that very short telomeres (<1st percentile for age) in lymphocytes, naïve T-cells, and B-cells were sensitive and specific for the diagnosis of DC (
Disclosures: Lansdorp:Repeat Diagnostics: Equity Ownership.