The main goal of this work was to conduct a population genetic analysis of RFLP detected in the TG gene and to develop a system of molecular genetic studies of hereditary thyroid diseases associated with polynucleotide rearrangements in the structure of TG. A population genetic analysis of RFLP detected in the TG gene was carried out. When splitting blood samples of healthy Tashkent residents with EcoRV and Taql restriction enzymes, 2 pairs of alternative variants of normal RFLP were detected - 13.8 or 8.5 and 5.8 or 6.2 bp respectively. In order to detect RFLP in the TG gene for congenital hypothyroidism, DNA samples from 2 families (mother, father, daughter) with a clinical diagnosis of congenital hypothyroidism were analyzed and the same variants of RFLP found in healthy individuals.