Lack of reported mutations in a Japanese case of toxic multinodular goiter.

We describe a toxic multinodular goiter that was subjected to genomic sequencing of the thyroid-stimulating hormone receptor and the alpha-subunit of the stimulatory guanine nucleotide-binding protein. No mutation was detected in either gene. While frequent occurrence of thyroid-stimulating hormone receptor gene mutations in toxic multinodular goiters has been reported in areas such as part of Europe with a relatively high prevalence of iodine deficiency, toxic multinodular goiters in areas with an abundance of dietary iodine such as Japan seem unlikely to involve mutations of this gene.