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

Objective To study the relationship of the T354P,G395R mutation of human sodium/iodide symporter gene and congenital hypothyroidism in Linyi.Method The T354P and G395R mutation were studied by polymerase chain reaction and restriction enzyme analysis in groups of congenital hypothyroidism(n=50 patients whose thyroids were normal or with diffuse goiter ,without gland in place defects and ectopy who were from neonatal screening disease central )and normal controls(n=106 healthy individuals who did not have any thyroid disorder, whose thyroids were normal).Genomic DNA was isolated from peripheral blood cells of the patients .PCR was used to amplify genomic DNA fragments containing the T354P or G395R mutation.Because the T354P mutation itself dose 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 mutant allele produced three fragments of 142bp,38bp and 22bp,while the 164bp fragment in the wild-type allele remained undisgested. Exon 9 and 10 were coamplified with the intervening intron 9.Digested by AlwI ,when the G395R mutation exists,the 370bp PCR product remains undigested.In the wild-type allele,there is an AlwI site in exon 10,which produces fragments of 267bp and 103bp. Combined by higher concentration agarose gel electrophoresis and staining with ethidium bromide ,the allele among each group were compared.Results All of the HaeIII digested PCR-amplified fragments from the two groups were 164bp and 38bp,the AlwI digested PCR-amplified fragments were 267bp and 103bp .Our results indicated that the T354P or G395R mutation were absent in the genomic DNA in both CH and healthy individuals.Conclusion The results suggested that T354P and G395R mutation of human sodium/iodide symporter gene may not be the main reason for congenital hypothyroidism infants of Linyi.