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The gene of the sodium/iodide symporter (NIS) has recently been cloned
and two reports at this meeting showed abnormalities in the gene in subjects
with an iodide trapping defect.
Kosugi et al., Kyoto, Japan, describe a mutation at position 1060 of a subject in whom the abnormality was described 35 years ago. Pohlenz et al., Chicago, IL, USA, described a iodide trapping effect in a 12 year old girl who appeared to be compound heterozygote for a non-functional NIS inherited from the father with a mutation at nucleotide 1146 and a truncated NIS presumably inherited from the mother. Nogueira et al., Sao Paulo, Brazil, and Amsterdam, The Netherlands, describe their studies in 4 unrelated families with 9 affected individuals with inactivating mutations in the gene of thyroid peroxidase. They correlate the mutations in the genotype with phenotype i.e. expression of functional TPO activity. Two different mutations were detected, one at position 1277 and one at position 2505. No TPO protein was present in patients with the first mutation, and only marginally present in patients with the second mutation. |
