The Investigation Of T354P, G395R Human Sodium/Iodide Symporter Gene Mutation In Congenital Hypothyroidism

Objective To study the association of the T354P, G395R mutation of human sodium/iodide symporter gene and congenital hypothyroidism in Qingdao.Method The T354P and G395R mutation were investigated by polymerase chain reaction and restriction enzyme analysis in groups of congenital hypothyroidism (n=47) and health control (n=100). Genomic DNA was isolated from peripheral blood. PCR was used to amplify genomic DNA fragment containing the T354P or G395R mutation. Because the T354P mutation itself does not change available restriction enzyme sites, we performed PCR using a special primer which had a mismatch nucleotide to amplify a 202bp fragment containing exon 9. After digestion with HaeIII, the mutation allele produced three fragments of 22bp, 142bp, and 38bp, while the wild-type allele remained 164bp fragment. Exon 9 and 10 were coamplified with the intervening intron 9. Digested by BspPI , the wild-type allele produced two fragments of 267bp and 103bp. When the G395R mutation existed, the 370bp PCR product remained undigested. Digested product were visualized after electrophoresis in an agarose gel.Results All of the Haelll digested PCR-amplified fragments from the both groups were 38bp and 164bp, meanwhile the BspPI digested fragments were 267bp and 103bp.Our results indicated that the T354P or G395R mutation were absent in the genomic DNA in both CH and normal control.Conclusion The results suggested that T354P and G395R mutation of human sodium/iodide symporter gene may not be the main reason for congenital hypothyroidism in Qingdao.