TERT / TERC variants

TERT and TERC are the two core parts of telomerase. Telomerase is the enzyme that rebuilds the protective caps (telomeres) on your chromosomes. TERT (telomerase reverse transcriptase) does the building. TERC (telomerase RNA component) is the RNA template it copies to add more TTAGGG repeats. Common single-letter variants in both genes are among the strongest genetic hits for telomere length in your white blood cells. They nudge your risk of cancer, heart disease, and lung fibrosis, in proportion to that effect. Rare, single broken copies of TERT or TERC are a different story. They cause dominant 'telomere biology disorders'. That spectrum includes dyskeratosis congenita, familial idiopathic pulmonary fibrosis, aplastic anemia, and liver cirrhosis. These happen because fast-renewing tissues run out of telomere. The conditions also tend to strike earlier in each generation (anticipation). The gap between mild common variants and severe rare mutations shows how finely tuned telomere upkeep is.

Last reviewed: June 22, 2026

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