In conclusions, in this study we analyzed 63 FPTC patients for the presence of the A339V mutation in thyroid transcription factor-1 (TITF-1/NKX2.1) in order to correlate that mutation with the predisposition to develop familial form of thyroid cancer demonstrated by shorter telomere length which may contribute to genetic instability and thyroid cancer development. The gene discussed is NKX2-1; the disease is thyroid cancer.