0
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found

      Clinical Description of Infants with Congenital Hypothyroidism and Iodide Organification Defects

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Aims: To describe the phenotype of a large group of children with congenital hypothyroidism (CH) and iodide organification defect (IOD), suspected based on normal thyroid position and abnormal perchlorate discharge test, as first step of a project evaluating correlations between phenotypes and genotypes. Methods: 71 children born in Paris between 1980 and 2006 were included. Two groups were defined according to perchlorate discharge: total IOD (TIOD) when the release was above 90% and partial IOD (PIOD) between 10 and 90%. Comparisons between groups were performed using SPSS 14.0 for Windows. Results: The incidence of IOD over the 2003–2006 period was 1:20,660. Of the 71 children, 61 had PIOD and 10 TIOD. Compared to PIOD, TIOD was characterized by greater clinical severity. A wide spectrum of clinical features was seen in the PIOD group. Evolution showed transient hypothyroidism in 10/61 patients with PIOD and 1/10 TIOD patients. Conclusions: Severe presentation in the majority of TIOD patients suggests dysfunction of a key iodide-organification enzyme. In contrast, the variety of clinical features in PIOD group suggests that diverse mechanisms may lead to PIOD, such as delayed or reduced activity of enzymes involved in hormonogenesis or defects in iodine storage and release.

          Related collections

          Most cited references 26

          • Record: found
          • Abstract: found
          • Article: not found

          Pendred syndrome is caused by mutations in a putative sulphate transporter gene (PDS).

          Pendred syndrome is a recessively inherited disorder with the hallmark features of congenital deafness and thyroid goitre. By some estimates, the disorder may account for upwards of 10% of hereditary deafness. Previous genetic linkage studies localized the gene to a broad interval on human chromosome 7q22-31.1. Using a positional cloning strategy, we have identified the gene (PDS) mutated in Pendred syndrome and found three apparently deleterious mutations, each segregating with the disease in the respective families in which they occur. PDS produces a transcript of approximately 5 kb that was found to be expressed at significant levels only in the thyroid. The predicted protein, pendrin, is closely related to a number of known sulphate transporters. These studies provide compelling evidence that defects in pendrin cause Pendred syndrome thereby launching a new area of investigation into thyroid physiology, the pathogenesis of congenital deafness and the role of altered sulphate transport in human disease.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Genetics of congenital hypothyroidism.

            Congenital hypothyroidism is the most common neonatal metabolic disorder and results in severe neurodevelopmental impairment and infertility if untreated. Congenital hypothyroidism is usually sporadic but up to 2% of thyroid dysgenesis is familial, and congenital hypothyroidism caused by organification defects is often recessively inherited. The candidate genes associated with this genetically heterogeneous disorder form two main groups: those causing thyroid gland dysgenesis and those causing dyshormonogenesis. Genes associated with thyroid gland dysgenesis include the TSH receptor in non-syndromic congenital hypothyroidism, and Gsalpha and the thyroid transcription factors (TTF-1, TTF-2, and Pax-8), associated with different complex syndromes that include congenital hypothyroidism. Among those causing dyshormonogenesis, the thyroid peroxidase and thyroglobulin genes were initially described, and more recently PDS (Pendred syndrome), NIS (sodium iodide symporter), and THOX2 (thyroid oxidase 2) gene defects. There is also early evidence for a third group of congenital hypothyroid conditions associated with iodothyronine transporter defects associated with severe neurological sequelae. This review focuses on the genetic aspects of primary congenital hypothyroidism.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Congenital hypothyroidism: etiologies, diagnosis, and management.

               S LaFranchi (1999)
              Congenital hypothyroidism is a common preventable cause of mental retardation. The overall incidence is approximately 1:4000; females are affected about twice as often as males. Approximately 85% of cases are sporadic, while 15% are hereditary. The most common sporadic etiology is thyroid dysgenesis, with ectopic glands more common than aplasia or hypoplasia. While the pathogenesis of dysgenesis is largely unknown, some cases are now discovered to be the result of mutations in the transcription factors PAX-8 and TTF-2. Loss of function mutations in the thyrotropin (TSH) receptor have been demonstrated to cause some familial forms of athyreosis. The most common hereditary etiology is the inborn errors of thyroxine (T4) synthesis. Recent mutations have been described in the genes coding for the sodium/iodide symporter, thyroid peroxidase (TPO), and thyroglobulin. Transplacental passage of a maternal thyrotropin receptor blocking antibody (TRB-Ab) causes a transient form of familial congenital hypothyroidism. The vast majority of infants are now diagnosed after detection through newborn screening programs using a primary T4-backup TSH or primary TSH test. Screening test results must be confirmed by serum thyroid function tests. Thyroid scintigraphy, using 99mTc or 123I, is the most accurate diagnostic test to detect thyroid dysgenesis or one of the inborn errors of T4 synthesis. Thyroid sonography is nearly as accurate, but it may miss some cases of ectopic glands. If maternal antibody-mediated hypothyroidism is suspected, measurement of maternal and/or neonatal TRB-Ab will confirm the diagnosis. The goals of treatment are to raise the serum T4 as rapidly as possible into the normal range, adjust the levothyroxine dose with growth to keep the serum T4 (or free T4) in the upper half of the normal range and the TSH normal, and maintain normal growth and development while avoiding overtreatment. An initial starting dose of 10-15 microg/kg per day is recommended; this dose will decrease on a weight basis over time. Serum T4 (or free T4) and TSH should be monitored every 1-2 months in the first year of life and every 2-3 months in the second and third years.
                Bookmark

                Author and article information

                Journal
                HRE
                Horm Res Paediatr
                10.1159/issn.1663-2818
                Hormone Research in Paediatrics
                S. Karger AG
                1663-2818
                1663-2826
                2008
                October 2008
                05 September 2008
                : 70
                : 4
                : 240-248
                Affiliations
                aPediatric Endocrinology Unit, Hôpital Necker-Enfants Malades, AP-HP and University Paris Descartes, Faculty Necker, INSERM U845, Paris, France; bDepartment of Pediatrics, University of Verona, Verona, Italy; cPediatric Endocrinology Unit, Hôpital Armand Trousseau, AP-HP and University Paris Curie, and dPediatric Endocrinology Unit, Hôpital Robert Debré, AP-HP and University Paris Diderot, INSERM U457, Paris, France
                Article
                151597 Horm Res 2008;70:240–248
                10.1159/000151597
                18772598
                © 2008 S. Karger AG, Basel

                Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

                Page count
                Figures: 2, Tables: 5, References: 39, Pages: 9
                Categories
                Original Paper

                Comments

                Comment on this article