Clinical and laboratory data from patients with hTERC variants
hTERC sequence variant . | Clinical diagnosis . | Telomere length . | Telomerase activity* . |
|---|---|---|---|
| Core domain | |||
| C116T | AA (severe pancytopenia) | + | - |
| C204G | AA (moderate pancytopenia) | + | - |
| A117C | AA (severe pancytopenia) | + | - |
| G143A | DC | + | - |
| Δ96-97 | DC | + | - |
| CR4-CR5 domain | |||
| G305A | AA (moderate) | ++ | + |
| G322A | MDS | ND | + |
| H/ACA domain | |||
| Δ389-390 | Essential thrombocythemia | ND | - |
| C408G | DC | + | - |
| G450A | AA (severe) | +++ | +++ |
| CR7 domain | |||
| Δ378-451 | DC | ++ | - |
| Hypervariable paired region | |||
| G228A | AA (moderate) or healthy | +++ | +++ |
hTERC sequence variant . | Clinical diagnosis . | Telomere length . | Telomerase activity* . |
|---|---|---|---|
| Core domain | |||
| C116T | AA (severe pancytopenia) | + | - |
| C204G | AA (moderate pancytopenia) | + | - |
| A117C | AA (severe pancytopenia) | + | - |
| G143A | DC | + | - |
| Δ96-97 | DC | + | - |
| CR4-CR5 domain | |||
| G305A | AA (moderate) | ++ | + |
| G322A | MDS | ND | + |
| H/ACA domain | |||
| Δ389-390 | Essential thrombocythemia | ND | - |
| C408G | DC | + | - |
| G450A | AA (severe) | +++ | +++ |
| CR7 domain | |||
| Δ378-451 | DC | ++ | - |
| Hypervariable paired region | |||
| G228A | AA (moderate) or healthy | +++ | +++ |
Sources for the original descriptions, associated clinical findings, and telomere length data are as follows: C116T and C204G22 ; G143A and Δ96-9724 ; A117C and Δ389-390, present study; G305A and G322A23 ; and C408G and Δ378-451.25 Original descriptions, associated clinical findings, and telomere length data for A117C, G305A, and G322A are from the present study. Telomere lengths of peripheral blood lymphocytes are expressed in comparison to those of age-matched healthy individuals assayed simultaneously, as reported in the indicated references: +++, within reference range; ++, 2 kb to 3 kb shorter than the reference range; +, 3 kb to 6 kb shorter than the reference range; ND, not determined.
The telomerase activity of each variant was determined in this study using reconstituted VA13+hTERT cells, and is expressed in comparison to that of wild-type hTERC (+++, 20%-100%; ++, 2%-20%; +, 1%-2%; -, undetectable), based on 2 or 3 independent measurements