Iodide handling disorders (NIS, TPO, TG, IYD)

Best Pract Res Clin Endocrinol Metab. 2017 Mar;31(2):195-212. doi: 10.1016/j.beem.2017.03.006. Epub 2017 Apr 4.


Iodide Handling Disorders lead to defects of the biosynthesis of thyroid hormones (thyroid dyshormonogenesis, TD) and thereafter congenital hypothyroidism (CH), the most common endocrine disease characterized by low levels of circulating thyroid hormones. The prevalence of CH is 1 in 2000-3000 live births. Prevention of CH is based on prenatal diagnosis, carrier identification, and genetic counseling. In neonates a complete diagnosis of TD should include clinical examination, biochemical thyroid tests, thyroid ultrasound, radioiodine or technetium scintigraphy and perchlorate discharge test (PDT). Biosynthesis of thyroid hormones requires the presence of iodide, thyroid peroxidase (TPO), a supply of hydrogen peroxide (DUOX system), an iodine acceptor protein, thyroglobulin (TG), and the rescue and recycling of iodide by the action of iodotyrosine deiodinase or iodotyrosine dehalogenase 1 (IYD or DEHAL1). The iodide transport is a two-step process involving transporters located either in the basolateral or apical membranes, sodium iodide symporter (NIS) and pendrin (PDS), respectively. TD has been linked to mutations in the solute carrier family 5, member 5 transporter (SLC5A5, encoding NIS), solute carrier family 26, member 4 transporter (SLC26A4, encoding PDS), TPO, DUOX2, DUOXA2, TG and IYD genes. These mutations produce a heterogeneous spectrum of CH, with an autosomal recessive inheritance. Thereafter, the patients are usually homozygous or compound heterozygous for the gene mutations and the parents, carriers of one mutation. In the last two decades, considerable progress has been made in identifying the genetic and molecular causes of TD. Recent advances in DNA sequencing technology allow the massive screening and facilitate the studies of phenotype variability. In this article we included the most recent data related to disorders caused by mutations in NIS, TPO, TG and IYD.

Keywords: iodotyrosine deiodinase; sodium iodide symporter; thyroglobulin; thyroid peroxidase.

Publication types

  • Review

MeSH terms

  • Autoantigens / genetics*
  • Autoantigens / metabolism
  • Congenital Hypothyroidism / genetics*
  • Congenital Hypothyroidism / metabolism
  • Genetic Counseling
  • Humans
  • Hydrolases / genetics*
  • Hydrolases / metabolism
  • Iodide Peroxidase / genetics*
  • Iodide Peroxidase / metabolism
  • Iodides / metabolism*
  • Iron-Binding Proteins / genetics*
  • Iron-Binding Proteins / metabolism
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Mutation*
  • Symporters / genetics*
  • Symporters / metabolism
  • Thyroglobulin / genetics*
  • Thyroglobulin / metabolism
  • Thyroid Gland / metabolism
  • Thyroid Hormones / metabolism


  • Autoantigens
  • Iodides
  • Iron-Binding Proteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • Symporters
  • Thyroid Hormones
  • sodium-iodide symporter
  • Thyroglobulin
  • TPO protein, human
  • Iodide Peroxidase
  • Hydrolases
  • IYD protein, human