Transient congenital hypothyroidism (TCH) refers to congenital hypothyroidism which spontaneously resolves in the first few months or years of life. Currently, there is a paucity of reliable markers predicting TCH at diagnosis, and the diagnosis is established following the withdrawal of levothyroxine therapy around 3 years of age. The incidence of TCH is increasing, and it is a major contributor to the overall increase in the incidence of CH in recent studies. Both genetic factors, in particular mutations affecting DUOX2 and DUOXA2, and environmental factors, for example, iodine deficiency and excess, anti- TSHR antibodies and exposure to antithyroid or iodine-rich medications, may cause TCH. Resolution of TCH in childhood may reflect both normal thyroid physiology (decreased thyroid hormone biosynthesis requirements after the neonatal period) and clearance or cessation of environmental precipitants. The relative contributions and interactions of genetic and environmental factors to TCH, and the extent to which TCH may be prevented, require evaluation in future population-based studies.
Catherine Peters and Nadia Schoenmakers
Celia Aradillas-García, Martha Rodríguez-Morán, María Eugenia Garay-Sevilla, Juan Manuel Malacara, Ramón Alberto Rascon-Pacheco, and Fernando Guerrero-Romero
Several cutoff points of the homeostasis model assessment of insulin resistance (HOMA-IR; varying from 2.5 to 4.0) have been suggested for diagnosing IR in youth. In this study, we determined the distribution of the HOMA-IR in Mexican children and adolescents.
Design and methods
A total of 6132 children and adolescents from San Luis Potosi, León, Queretaro, and Durango, which are cities in central and northern Mexico, were enrolled in a population-based cross-sectional study. Eligible participants were apparently healthy children and adolescents aged 6–18 years. Pregnancy and the presence of chronic illnesses were exclusion criteria.
A total of 3701 (60.3%) girls and 2431 (39.7%) boys were included in this study. In the overall population, the mean body mass index, insulin levels, and fasting glucose levels were 21.8±1.3 kg/m2, 7.1±3.2 μU/ml, and 86.2±10.0 mg/dl respectively. The concentrations of insulin and fasting glucose gradually increased from 6 to 12 years of age, whereas the concentrations tended to plateau in the 13- to 18-year-old population. The absolute mean of the HOMA-IR was 2.89±0.7. The HOMA-IR gradually increased with age and reached a plateau at 13 years of age.
Because the insulin concentrations, glucose levels, and HOMA-IR exhibited a gradual increase with age that was not related to obesity, our results suggested that the evaluation of IR in children should be based on percentiles of the HOMA-IR rather than a dichotomous value derived from a single cutoff point.
S Bellone, F Prodam, S Savastio, D Avanzo, A Pagani, L Trovato, G E Walker, G Genoni, and G Bona
Ghrelin is a peptide with multiple functions that circulates in acylated (AG) and unacylated (UAG) forms. However, the role of ghrelin in neonates (NN) remains to be clarified.
The aim of this study was to determine ghrelin concentrations of the two forms in NN to clarify their biological roles. As such, ghrelin levels at birth were compared with those in later life.
Setting and design
Tertiary Care Center. In this cross-sectional study, we evaluated AG, UAG, AG/UAG ratio, and insulin levels in venous cord blood from NN and in fasted normal weight (NW) and obese (OB) children, both prepubertal and pubertal.
We studied 82 NN, 82 NW, and 58 OB children.
AG levels were lower in NN than in NW and OB children (P<0.0001), more specifically the prepubertal NW and OB children (P<0.0001). UAG levels were higher in NN than in NW and OB children (P<0.0001). Therefore, the AG/UAG ratio was lower in NN than in NW and OB children (P<0.0001). NN showed insulin levels similar to NW and lower than OB children (P<0.0001). At birth UAG was positively correlated with AG (Pearson: 0.425; P<0.0001) and negatively with insulin (−0.253; P<0.02). In NW and OB, UAG and AG were positively correlated to each other and negatively correlated with insulin and body mass index (−0.566; P<0.0001).
NN compared with children, showed higher UAG and lower AG levels. The AG/UAG ratio showed a very different profile in NN, being lower than in NW and OB children, thus suggesting a different metabolic function for the two forms in NN. Further studies are needed to clarify the exact role of the different ghrelin forms in NN.
D T Ward, M Z Mughal, M Ranieri, M M Dvorak-Ewell, G Valenti, and D Riccardi
Loss-of-function calcium-sensing receptor (CAR) mutations cause elevated parathyroid hormone (PTH) secretion and hypercalcaemia. Although full Car deletion is possible in mice, most human CAR mutations result from a single amino acid substitution that maintains partial function. However, here, we report a case of neonatal severe hyperparathyroidism (NSHPT) in which the truncated CaR lacks any transmembrane domain (CaRR392X), in effect a full CAR ‘knockout’.
The infant (daughter of distant cousins) presented with hypercalcaemia (5.5–6 mmol/l corrected calcium (2.15–2.65)) and elevated PTH concentrations (650–950 pmol/l (12–81)) together with skeletal demineralisation. NSHPT was confirmed by CAR gene sequencing (homozygous c.1174C-to-T mutation) requiring total parathyroidectomy during which only two glands were located and removed, resulting in normalisation of her serum PTH/calcium levels.
Design and methods
The R392X stop codon was inserted into human CAR and the resulting mutant (CaRR392X) expressed transiently in HEK-293 cells.
CaRR392X expressed as a 54 kDa dimeric glycoprotein that was undetectable in conditioned medium or in the patient's urine. The membrane localisation observed for wild-type CaR in parathyroid gland and transfected HEK-293 cells was absent from the proband's parathyroid gland and from CaRR392X-transfected cells. Expression of the mutant was localised to endoplasmic reticulum consistent with its lack of functional activity.
Intriguingly, the patient remained normocalcaemic throughout childhood (2.5 mM corrected calcium, 11 pg/ml PTH (10–71), age 8 years) but exhibited mild asymptomatic hypocalcaemia at age 10 years, now treated with 1-hydroxycholecalciferol and Ca2 + supplementation. Despite representing a virtual CAR knockout, the patient displays no obvious pathologies beyond her calcium homeostatic dysfunction.
Carmen Freire, Rosa Ramos, Esperanza Amaya, Mariana F Fernández, Piedad Santiago-Fernández, Maria-Jose Lopez-Espinosa, Juan-Pedro Arrebola, and Nicolas Olea
An association between thyroid function during pregnancy or infancy and neurodevelopment in children has been demonstrated. We aimed to investigate whether newborn TSH concentrations are related to subsequent neurocognitive development.
We conducted a longitudinal study on 178 children from a general population birth cohort in Granada (Spain) born in 2000–2002.
TSH concentrations were measured in umbilical cord blood, and cognitive functions were assessed at 4 years of age using the McCarthy's scales of children's abilities (MSCA). Organochlorine (OC) compound concentrations and the combined oestrogenicity (total effective xeno-oestrogenic burden (TEXB)) were also determined in the placentae.
Mean newborn TSH was 3.55 mU/l (range=0.24–17 mU/l). In multivariate regression analyses, adjusting for maternal and child characteristics, higher newborn TSH concentrations showed a decrease of 3.51 and 3.15 points on the MSCA general cognitive and executive function scores respectively and were associated with a higher risk of scoring below the 20th percentile (P20) on the quantitative score (odds ratio (OR)=2.64). Children with TSH in the upper quartile (4.19–17.0 mU/l) were at higher risk of scoring <P20 on span memory (OR=5.73), whereas children with TSH in the second quartile (2.05–2.95 mU/l) were at lower risk of scoring <P20 on the verbal scale (OR=0.24). Neonatal TSH status was also associated with general cognitive and executive function outcomes when controlling for prenatal exposure to OCs or placental TEXB.
Newborn thyroid hormone status expressed by TSH in cord blood may adversely affect later cognitive function. A more thorough screening for neonatal thyroid deficiency is warranted.
P Dimitri, J T Warner, J A L Minton, A M Patch, S Ellard, A T Hattersley, S Barr, D Hawkes, J K Wales, and J W Gregory
Mutations in the GLI-similar 3 (GLIS3) gene encoding the transcription factor GLIS3 are a rare cause of neonatal diabetes and congenital hypothyroidism with six affected cases from three families reported to date. Additional features, described previously, include congenital glaucoma, hepatic fibrosis, polycystic kidneys, developmental delay and facial dysmorphism.
We report two new cases from unrelated families with distinct novel homozygous partial GLIS3 deletions. Both patients presented with neonatal diabetes mellitus, severe resistant hypothyroidism in the presence of elevated thyroglobulin and normal thyroid anatomy, degenerative liver disease, cystic renal dysplasia, recurrent infections and facial dysmorphism. These novel mutations have also resulted in osteopenia, bilateral sensorineural deafness and pancreatic exocrine insufficiency, features that have not previously been associated with GLIS3 mutations. Gene dosage analysis showed that the parents were carriers of a deletion encompassing exons 1–2 (case 1) or exons 1–4 (case 2) of the 11 exon gene. Genome-wide SNP analysis did not reveal a common ancestral GLIS3 haplotype in patient 2.
Our results confirm partial gene deletions as the most common type of GLIS3 mutations, accounting for four of five families identified to date. We propose that mutations in GLIS3 lead to a wider clinical phenotype than previously recognised. We also report the first case of a recessive GLIS3 mutation causing neonatal diabetes and congenital hypothyroidism in a child from a non-consanguineous pedigree, highlighting the importance of molecular genetic testing in any patient with this phenotype.
Nicoletta Bisacchi, Milva Orquidea Bal, Laura Nardi, Ilaria Bettocchi, Graziana D'Addabbo, Veronica Conti, Sara Monti, Franco D'Alberton, Alessandro Cicognani, and Alessandra Cassio
To compare the psychological adjustment and behaviour of congenital hypothyroidism (CH) children and their parents with a control group.
A cross-sectional study was carried out with 84 CH subjects diagnosed by neonatal screening (range 2.7–18.6 years), subdivided into four age groups: group 1 (2–5 years); group 2 (6–10 years); group 3 (11–13 years); and group 4 (14–18 years) and was compared with an age-matched control group. Patients were assessed using two questionnaires: Child Behaviour Checklist for parents and Youth Self-Report for children over 11 years of age.
In groups 1, 3 and 4, total score (TS), internalising score (IS=problems within the self) and externalising score (ES=conflicts with other people) as reported by parents were not significantly different in CH patients and in controls. In group 2, parents of CH children showed values of TS (P<0.05), IS (P<0.05), ES (P<0.05) and scores on other scales significantly higher than controls. In self-reports of groups 3 and 4, the behavioural scales were not significantly different in CH patients and in controls.
Paediatricians should be informed about the increased risk of the development of behavioural problems at primary school age in CH patients. At this age special attention should be paid to parental worries and anxiety. However, it can be reassuring for the patients and parents to know that the problems may be related to CH, and that they may spontaneously disappear.
Helton Estrela Ramos, Melina Morandini, Aurore Carré, Elodie Tron, Corinne Floch, Laurent Mandelbrot, Nathalie Neri, Benoit De Sarcus, Albane Simon, Jean Paul Bonnefont, Jeanne Amiel, Isabelle Desguerre, Vassili Valayannopoulos, Mireille Castanet, and Michel Polak
Monocarboxylate transporter 8 (MCT8 or SLC16A2) mutations cause X-linked Allan–Herndon–Dudley syndrome. Heterozygous females are usually asymptomatic, but pregnancy may modify thyroid function and MCT8 is expressed in the placenta, suggesting that maternal and fetal abnormalities might develop even in the absence of MCT8 fetal mutation. Genetic counseling is so far based on X-linked transmission, and prenatal diagnosis is rarely performed.
To describe thyroid function and the prenatal diagnosis in pregnant mothers harboring heterozygous MCT8 mutations and management of the persistent maternal hypothyroxinemia.
Two women heterozygous for MCT8 mutations (c.1690G>A and c.1393-1G>C) were monitored throughout pregnancy.
Prenatal diagnosis included sex determination, direct MCT8 sequencing, and familial linkage analysis. Ultrasonography and hormonal assays for maternal thyroid function evaluation were performed serially during pregnancy. Neonatal thyroid hormonal status was assessed.
None of the three fetuses (two males and one female) carried MCT8 mutations. One of the two heterozygous mothers revealed gestational hypothyroxinemia, prompting early levothyroxine (l-T4) therapy until delivery. The second heterozygous mother showed normal thyroid function but was preventively traited by l-T4 and all of the three neonates had normal thyroid hormone levels and thyroid gland at birth, suggesting advantages of prenatal care and/or compensatory mechanisms.
Heterozygous MCT8 women should be monitored for requirement of l-T4 therapy to prevent fetal and neonatal hypothyroidism and to avoid risk of potential cognitive delay due to gestational hypothyroxinemia. Moreover, when the disease-causing mutation is known and/or the first child is affected, prenatal diagnosis for male fetuses should be assessed early for MCT8 mutations by direct sequencing.
Anna G Angelousi, Drosos E Karageorgopoulos, Anastasios M Kapaskelis, and Matthew E Falagas
The severity of critical illness is associated with various patterns of thyroid hormone abnormalities. We sought to evaluate whether the outcome of patients with, specifically, sepsis or septic shock is associated with the thyroid function tests evaluated at diagnosis or admission in the intensive care unit (ICU).
We performed a systematic review of relevant studies by searching PubMed.
We included nine studies that all had a prospective cohort design. Seven involved children or neonates, and two involved adults. Mortality was the outcome evaluated in eight studies, while the length of ICU stay was evaluated in the remaining study. In univariate analysis, six of the nine included studies showed that either, free or total, triiodothyronine or thyroxine was lower in the group of patients with sepsis or septic shock who had unfavorable outcome than in those who had favorable outcome. Two other studies showed higher TSH values in the group of patients with unfavorable outcome. No significant relevant findings were observed in the remaining study. Regarding the correlation of sepsis prognostic scoring systems with thyroid function tests, the three studies that provided specific relevant data showed variable findings.
Most of the relevant studies identified favor the concept that decreased thyroid function at baseline might be associated with a worse outcome of patients with sepsis or septic shock. Although these findings are not consistent, the role of thyroid function in affecting or merely predicting the outcome of sepsis or septic shock merits further investigation.
Maik Welzel, Leyla Akin, Anja Büscher, Tülay Güran, Berthold P Hauffa, Wolfgang Högler, Julia Leonards, Beate Karges, Heiner Kentrup, Birgul Kirel, Emine Esin Yalinbas Senses, Neslihan Tekin, Paul-Martin Holterhus, and Felix G Riepe
Pseudohypoaldosteronism type 1 (PHA1) is a monogenic disease caused by mutations in the genes encoding the human mineralocorticoid receptor (MR) or the α (SCNN1A), β (SCNN1B) or γ (SCNN1G) subunit of the epithelial Na+ channel (ENaC). While autosomal dominant mutation of the MR cause renal PHA1, autosomal recessive mutations of the ENaC lead to systemic PHA1. In the latter, affected children suffer from neonatal onset of multi-organ salt loss and often exhibit cystic fibrosis-like pulmonary symptoms.
We searched for underlying mutations in seven unrelated children with systemic PHA1, all offsprings of healthy consanguineous parents.
Methods and results
Amplification of the SCNN1A gene and sequencing of all 13 coding exons unraveled mutations in all of our patients. We found five novel homozygous mutations (c.587_588insC in two patients, c.1342_1343insTACA, c.742delG, c.189C>A, c.1361-2A>G) and one known mutation (c.1474C>T) leading to truncation of the αENaC protein. All parents were asymptomatic heterozygous carriers of the respective mutations, confirming the autosomal recessive mode of inheritance. Five out of seven patients exhibited pulmonary symptoms in the neonatal period.
The α subunit is essential for ENaC function and mutations truncating the pore-forming part of the protein leading to systemic PHA1. Based on current knowledge, the pulmonary phenotype cannot be satisfactorily predicted.