TERT and Down syndrome: However, fingernail changes were also found in one of the three individuals with 5p– syndrome having two copies of the TERT gene, and equally low numbers of circulating blood progenitor cells were present in all three 5p– individuals with two copies of TERT. Early graying of hair was not seen in individuals with 5p– syndrome and with two copies of TERT, but all three were below the age of 10.