Update on Neonatal Isolated Hyperthyrotropinemia: A Systematic Review

The purpose of this paper was to systematically summarize the published literature on neonatal isolated hyperthyrotropinemia (HTT), with a focus on prevalence, L-T4 management, re-evaluation of thyroid function during infancy or childhood, etiology including genetic variation, thyroid imaging tests, and developmental outcome. Electronic and manual searches were conducted for relevant publications, and a total of 46 articles were included in this systematic review. The overall prevalence of neonatal HTT was estimated at 0.06%. The occurrence of abnormal imaging tests was found to be higher in the persistent than in the transient condition. A continuous spectrum of thyroid impairment severity can occur because of genetic factors, environmental factors, or a combination of the two. Excessive or insufficient iodine levels were found in 46% and 16% of infants, respectively. Thirty-five different genetic variants have been found in three genes in 37 patients with neonatal HTT of different ethnic backgrounds extracted from studies with variable design. In general, genetic variants reported in the TSHR gene, the most auspicious candidate gene for HTT, may explain the phenotype of the patients. Many practitioners elect to treat infants with HTT to prevent any possible adverse developmental effects. Most patients with thyroid abnormalities and/or carrying monoallelic or biallelic genetic variants have received L-T4 treatment. For all those neonates on treatment with L-T4, it is essential to ensure follow-up until 2 or 3 years of age and to conduct medically supervised trial-off therapy when warranted. TSH levels were found to be elevated following cessation of therapy in 44% of children. Withdrawal of treatment was judged as unsuccessful, and medication was restarted, in 78% of cases. Finally, data extracted from nine studies showed that none of the 94 included patients proved to have a poor developmental outcome (0/94). Among subjects presenting with normal cognitive performance, 82% of cases have received L-T4 therapy. Until now, the precise neurodevelopmental risks posed by mild disease remain uncertain.Fil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Tellechea, Mariana Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentin

Primary thyroglossal duct carcinoma with lateral neck metastasis in an adolescent girl

Thyroglossal duct cysts are the most common thyroid developmental anomalies accounting for 75% of midline neck tumors in children. Carcinomas arising fromthis remnant are very rare in adults and even scarcer in pediatrics. Preoperative diagnosis is a challenge and appropriate treatment is controversial. We report the caseof a 13-year-old adolescent girl with a growing midline neck mass suspicious for a thyroglossal duct cyst who underwent a Sistrunk procedure. Histologic analysisrevealed the presence of a papillary carcinoma in the wall. She completed treatment with total thyroidectomy and radioactive iodine. Postablative whole body scanshowed an inferior neck metastasis. We discuss previous pediatric cases of this entity and the different options in the management strategy.Fil: Papendieck, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Gruñeiro Papendieck, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentin

Parenting styles and coping strategies in PKU early detected children

Phenylketonuria (PKU) requires tight control to prevent neurocognitive impairment but reports show that patients may present mild cognitive defects related to higher impulsivity. We hypothesize that chronic intervention may influence the parents and child bonding and the child´s resources to face problems. To describe the PKU parenting styles perceived by the children (PS) and their coping strategies (CS) assessing their relationship with impulsivity, 30 early diagnosed and adequately treated PKU children and 30 non PKU aged-paired controls (CG) were compared. The Argentine Children´s Coping Questionnaire, Argentine Scale Perception of the Relationship with Parents, WISC IV Comprehension Subtest, and CPT II test were administered. PKU PS were based on control: strict to pathologic in the mother and acceptable in the father (both p<0.05 vs. CG). Children significantly sought greater support and showed less emotional control when facing conflicts. These characteristics positively correlated with maternal control r:.383 and r:.398 (both p<0.05). Impulsivity was higher in PKU (p<0.05) but didn´t associate with PS or CS. Maternal strict control wasn´t linked to the higher impulsivity found (possibly neurobiologically based). Nevertheless, if both factors are present, patients may develop a psychological and/or behavioral trait of greater dependency and impulsivity that must be considered in their follow-up.Fil: Pardo Campos, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Psicología y Psicopedagogía; ArgentinaFil: Enacan, Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Valle, Maria G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentin

Antithyroid arthritis syndrome in a pediatric patient with Graves disease: A case Report

Las drogas antitiroideas (DAT) constituyen el tratamiento de primera línea en niños y adolescentes con Enfermedad de Graves (EG). Existe una multiplicidad de efectos adversos asociados al tratamiento farmacológico de esta patología, afortunadamente la gran mayoría poco frecuentes. De los efectos indeseados del tratamiento, la presencia de artritis constituye una rareza donde la disquisición entre la presencia de artralgias por el estado hipertiroideo, por otro trastorno autoinmune asociado a la EG o por el uso de DAT puede resultar un desafío para la continuidad del tratamiento.Se describe el cuadro clínico de una niña de 12 años con EG tratada con DAT (metimazol) que presentó poliartritis migratoria a los 20 días del inicio del tratamiento y posteriormente, tras la terapéutica definitiva del hipertiroidismo con I131, un síndrome miopático con elevación extrema de enzimas musculares requiriendo internación en cada una de estas circunstancias.Antithyroid drugs (ATD) represent the first choice of treatment in children and adolescents with Graves’ disease (GD). There is a multiplicity of pharmacologic treatment-linked side effects, most of which are rarely observed. Overall, arthritis is infrequent and the diagnostic disquisition between arthralgia associated with the hyperthyroid state, another autoimmune disorder linked to GD or to the use of ATD may result challenging to the endocrinologist.We report the case of a 12-year-old girl with GD treated with ATD (methimazole) who developed migratory polyarthritis 20 days after starting treatment and then, once definitive hyperthyroidism treatment with I131 was established, she suffered from a myopathic syndrome associated with extremely high muscular enzymes levels requiring hospitalization in both circumstances.Fil: Castro, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Papendieck, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentin

Parenting styles and coping strategies among patients with early detected and treated congenital hypothyroidism

Congenital hypothyroidism (CH), as any chronic disease, has an impact on the parent-child relationship and on the child’s resources to cope with conflicting situations. Objectives. To describe parenting styles according to the perception of children with CH and their coping strategies. Population and methods. Children aged 9-10 years who had CH detected by newborn screening and had received adequate treatment and a group without CH (control group). The Argentine Coping Questionnaire, the Argentine Scale for the Perception of Parent Relations, and the comprehension subtest of the Wechsler Intelligence Scale for Children III (WISC III) were used. Results were compared using a multivariate analysis of variance (MANOVA). Results. Sixty children with CH were included; they perceived that their mothers exercised a strict control and that their fathers showed more acceptance. They sought more support and became paralyzed more often in conflicting situations than the 60 children without CH. Conclusion. These findings may be associated with a higher level of dependence. They should be taken into consideration in CH care.Fil: Pardo Campos, Maria Laura. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Musso, Mariel Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro Interdisciplinario de Investigaciones en Psicología Matemática y Experimental Dr. Horacio J. A. Rimoldi; Argentina. Universidad Argentina de la Empresa; ArgentinaFil: Keselman, Ana Claudia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Gruñeiro Papendieck, Laura. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Bergadá, Ignacio. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentin

A novel mutation in intron 11 donor splice site, responsible of a rare genotype in thyroglobulin gene by altering the pre-mRNA splincing process: Cell expression and bioinformatic analysis

Thyroglobulin (TG) is a homodimeric glycoprotein synthesized by the thyroid gland. To date, two hundred twenty-seven variations of the TG gene have been identified in humans. Thyroid dyshormonogenesis due to TG gene mutations have an estimated incidence of approximately 1 in 100,000 newborns. The clinical spectrum ranges from euthyroid to mild or severe hypothyroidism. The purpose of the present study was to identify and characterize new variants in the TG gene. We report an Argentine patient with congenital hypothyroidism, enlarged thyroid gland and low levels of serum TG. Sequencing of DNA, expression of chimeric minigenes as well as bioinformatics analysis were performed. DNA sequencing identified the presence of compound heterozygous mutations in the TG gene: the maternal mutation consists of a c.3001+5G > A, whereas the paternal mutation consists of p.Arg296*. Minigen analysis of the variant c.3001+5A performed in HeLa, CV1 and Hek293T cell lines, showed a total lack of transcript expression. So, in order to validate that the loss of expression was caused by such variation, site-directed mutagenesis was performed on the mutated clone, which previously had a pSPL3 vector change, to give rise to a wild-type clone c.3001+5G, endorsing that the mutation c.3001+5G > A is the cause of the total lack of expression. In conclusion, we demonstrate that the c.3001+5G > A mutation causes a rare genotype, altering the splicing of the pre-mRNA. This work contributes to elucidating the molecular bases of TG defects associated with congenital hypothyroidism and expands our knowledge in relation to the pathologic roles of the position 5 in the donor splice site.Fil: Gomes Pio, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Molina, Maricel Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Siffo, Sofía. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; ArgentinaFil: Rivolta, Carina Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Targovnik, Hector Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentin

PKU: attention and executive profile in early detected and adequately treated patients

Antecedentes: Los pacientes fenilcetonúricos, incluso adecuadamente diagnosticados y tratados, pueden resultar con disfunción neurocognitiva. Objetivo: Evaluar la neurocognición de niños fenilcetonúricos y su relación con variables de la enfermedad y su tratamiento. Materiales y métodos: Estudio descriptivo y comparativo, expost-facto, transversal y prospectivo, efectuado del 2018 al 2019 en pacientes pediátricos con fenilcetonuria (grupo 1) de entre 9 y 11 años y un grupo control de niños sanos de la misma edad (grupo 2). Todos se evaluaron con una batería de pruebas para coeficiente intelectual y cognición. Resultados: Se estudiaron 30 niños con fenilcetonuria (18 varones y 12 niñas) (grupo 1) y 30 sin fenilcetonuria (grupo 2). EL coeficiente intelectual del grupo 1 fue normal, medio y menor al del grupo 2 (p < 0.01) con menor control ejecutivo asociado con la regulación de la impulsividad, la velocidad de procesamiento y la atención dividida y focalizada. En ambos grupos el coeficiente intelectual de ejecución y verbal fue normal promedio, con diferencias significativas en el coeficiente intelectual de ejecución, con un tamaño del efecto pequeño y sin diferencias significativas en el coeficiente intelectual verbal. Conclusión: Los niños fenilcetonúricos tuvieron repercusiones en las funciones cognitivas asociadas con el control ejecutivo y de atención. Evidenciaron vulnerabilidad de la función ejecutiva relacionada con el control de la enfermedad en la infancia.Background: Phenylketonuric patients, even properly diagnosed and treated, may result in neurocognitive dysfunction. Objetive: To evaluate neurocognition in phenylketonuric children and its relationship with disease variables and treatment. Materials and methods: Descriptive and comparative, expost-facto, cross-sectional, prospective study conducted from 2018 to 2019 in pediatric patients with phenylketonuria (group 1) aged 9 to 11 years and a control group of healthy children of the same age (group 2). All were assessed with a battery of tests for IQ and cognition. Results: Thirty children with phenylketonuria (18 boys and 12 girls) (group 1) and 30 without phenylketonuria (group 2) were studied. The IQ of group 1 was normal, average and lower than that of group 2 (p < 0.01) with lower executive control associated with impulsivity regulation, processing speed and divided and focused attention. In both groups, performance and verbal IQ were average normal, with significant differences in performance IQ, small effect size and no significant differences in verbal IQ. Conclusion: Phenylketonuric children had repercussions in cognitive functions associated with executive and attentional control. They evidenced vulnerability of executive function related to disease control in childhood.Fil: Pardo Campos, María. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Psicología y Psicopedagogía. Centro de Investigaciones en Psicología y Psicopedagogía; Argentina. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Enacan, Rosa. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Valle, Gabriela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentin

Phenylalanine Hydroxylase (PAH) Genotyping in PKU Argentine Patients

Phenylketonuria (PKU, OMIM 261600) is predominantly caused by mutations in the PAH gene. One hundred and three Argentine PKU patients were studied by Sanger sequencing; 101 were completely characterized (90.3% were compound heterozygotes). Fifty-four different pathogenic variants were identified. Mutations were distributed all along the PAH gene but concentrated in exon 7 (26%), 12 (12%), 11 (10%), and 6 (10%). 77% were missense, and 77% affected the enzyme catalytic domain, nine mutations accounted for 57% of 179 studied alleles: p.Arg261Gln (Allele frequency(AF):10.6%), c.1066-11G>A (AF:9,5%), p.Arg408Trp (AF:8,3%), p.Tyr414Cys (AF:5,5%), p.Ala403Val, p.Val388Met, and p.Arg158Gln (AF: 5% each), p.Leu48Ser, and p.Ile65Thr (AF:4% each). The predicted phenotype was assigned by Guldberg´s arbitrary value (AV) and compared with the clinical phenotype based in tolerance to Phe intake. 29.1% (n:30) were hyperphenylalaninemias, 18.5% (n:19) mild-PKU, 27.2% (n:28) moderate-PKU and 25.2 % (n:26) classical-PKU. Genotype/phenotype correlation was statistically significant (p<0.001) Overall concordance was 62,5%: 93.3% in hyperphenylalaninemia, 64.7% in mild-PKU and 65.4% in classical patients. The moderate-PKU showed a weak concordance (17%) with milder AV prediction than clinical assessment. 74% of discordant moderate patients harbored p.Arg261Gln, and p.Val388Met. Our cohort is highly heterogeneous, with predominant Mediterranean influence (mainly Spanish), but with differences with other Latin-American countries.Fil: Enacán, Rosa E.. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Miñana, Mariana Nuñez. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Fernandez, Luis. Universidad Autónoma de Madrid; EspañaFil: Valle, María Gabriela. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Salerno, Mercedes. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Fraga, Claudia I.. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Santos Simarro, Fernando. Universidad Autónoma de Madrid; EspañaFil: Prieto, Laura. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Lapunzina, Pablo. Universidad Autónoma de Madrid; EspañaFil: Specola, Norma. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Chiesa, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Gobierno de la Ciudad de Buenos Aires. Centro de Investigaciones Endocrinológicas "Dr. César Bergada". Fundación de Endocrinología Infantil. Centro de Investigaciones Endocrinológicas "Dr. César Bergada"; Argentina. Fundacion de Endocrinologia Infantil.; Argentin

Targeted Next-Generation Sequencing of Congenital Hypothyroidism-causative Genes Reveals Unexpected Thyroglobulin Gene Variants in Patients with Iodide Transport Defect

Congenital iodide transport defect is an uncommon autosomal recessive disorder caused by loss-of-function variants in the sodium iodide symporter (NIS)-coding SLC5A5 gene and leading to dyshormonogenic congenital hypothyroidism. Here, we conducted a targeted next-generation sequencing assessment of congenital hypothyroidism-causative genes in a cohort of nine unrelated pediatric patients suspected of having a congenital iodide transport defect based on the absence of 99mTc-pertechnetate accumulation in a eutopic thyroid gland. Although, unexpectedly, we could not detect pathogenic SLC5A5 gene variants, we identified two novel compound heterozygous TG gene variants (p.Q29* and c.177-2A\u3eC), three novel heterozygous TG gene variants (p.F1542Vfs*20, p.Y2563C, and p.S523P), and a novel heterozygous DUOX2 gene variant (p.E1496Dfs*51). Splicing minigene reporter-based in vitro assays revealed that the variant c.177-2A\u3eC affected normal TG pre-mRNA splicing, leading to the frameshift variant p.T59Sfs*17. The frameshift TG variants p.T59Sfs*17 and p.F1542Vfs*20, but not the DUOX2 variant p.E1496Dfs*51, were predicted to undergo nonsense-mediated decay. Moreover, functional in vitro expression assays revealed that the variant p.Y2563C reduced the secretion of the TG protein. Our investigation revealed unexpected findings regarding the genetics of congenital iodide transport defects, supporting the existence of yet to be discovered mechanisms involved in thyroid hormonogenesis

Molecular analysis of thyroglobulin mutations found in patients with goiter and hypothyroidism

Thyroid dyshormonogenesis due to thyroglobulin (TG) gene mutations have an estimated incidence of approximately 1 in 100,000 newborns. The clinical spectrum ranges from euthyroid to mild or severe hypothyroidism. Up to now, one hundred seventeen deleterious mutations in the TG gene have been identified and characterized. The purpose of the present study was to identify and characterize new mutations in the TG gene. We report eight patients from seven unrelated families with goiter, hypothyroidism and low levels of serum TG. All patients underwent clinical, biochemical and image evaluation. Sequencing of DNA, genotyping, as well as bioinformatics analysis were performed. Molecular analyses revealed three novel inactivating TG mutations: c.5560G>T [p.E1835*], c.7084G>C [p.A2343P] and c.7093T>C [p.W2346R], and four previously reported mutations: c.378C>A [p.Y107*], c.886C>T [p.R277*], c.1351C>T [p.R432*] and c.7007G>A [p.R2317Q]. Two patients carried homozygous mutations (p.R277*/p.R277*, p.W2346R/p.W2346R), four were compound heterozygous mutations (p.Y107*/p.R277* (two unrelated patients), p.R432*/p.A2343P, p.Y107*/p.R2317Q) and two siblings from another family had a single p.E1835* mutated allele. Additionally, we include the analysis of 48 patients from 31 unrelated families with TG mutations identified in our present and previous studies. Our observation shows that mutations in both TG alleles were found in 27 families (9 as homozygote and 18 as heterozygote compound), whereas in the remaining four families only one mutated allele was detected. The majority of the detected mutations occur in exons 4, 7, 38 and 40. 28 different mutations were identified, 33 of the 96 TG alleles encoded the change p.R277*. In conclusion, our results confirm the genetic heterogeneity of TG defects and the pathophysiological importance of the predicted TG misfolding and therefore thyroid hormone formation as a consequence of truncated TG proteins and/or missense mutations located within its ACHE-like domain.This study was funded by grants from the FONCyT-ANPCyT-MINCyT (PICT 2014-1193 to CMR, PICT 2012-1090 and PICT 2015–1811 to HMT), CONICET (PIP 2015-11220150100499 to CMR) and Universidad de Buenos Aires (UBACyT 2016-20020150100099BA to CMR)