Francesca Teofoli

Subclinical hypothyroidism in children and adolescents: a wide range of clinical, biochemical, and genetic factors involved.

OBJECTIVE The aim of the study was to examine clinical characteristics, biochemical parameters, and TSH-R gene variations in children and adolescents with subclinical hypothyroidism (SH) in order to evaluate their pattern of distribution in SH. PATIENTS We enrolled 88 patients, each having at least two TSH measurements above the upper limit of the reference range with normal free thyroid hormones and negative thyroid autoantibodies. MAIN OUTCOME MEASURES Clinical characteristics included height, weight, family history of thyroid diseases, thyroid volume, and echogenicity at ultrasonography. Biochemical parameters included TSH, free thyroid hormones, thyroid autoantibodies, and adjusted daily urinary iodine excretion (UIE). Genetic variations in the TSH-R gene were assessed. RESULTS The prevalence of overweight/obesity, positive family history of thyroid diseases, and thyroid hypoechogenicity was 28.4, 45.5, and 22.7%, respectively. Median TSH was higher in overweight/obese patients than in normal-weight ones (7.4 vs. 5.7 muIU/ml; P = 0.04) and in overweight/obese patients with hypoechogenicity than in those with normal ultrasound pattern (8.5 vs. 6.8 muIU/ml; P = 0.04). Adjusted daily UIE was lower in subjects without than in those with a positive family history of thyroid diseases (81 vs. 120 mug/d; P = 0.001). The prevalence of a positive family history of thyroid diseases was 1.9-fold higher in patients with nonsynonymous mutations in the TSH-R gene than in patients without any mutation (80 vs. 42%; P = 0.03). A novel mutation at position 1559 in exon 10 (W520X) was detected in one child. CONCLUSIONS Overweight/obesity, thyroid hypoechogenicity, and nonsynonymous mutations in the TSH-R gene are characterizing features of a large portion of SH children.

Thyrotropin receptor gene mutations and TSH resistance: variable expressivity in the heterozygotes

Objective  TSH resistance ranges from overt nonautoimmune hypothyroidism to subclinical hypothyroidism, defined as mild hyperthyrotrophinaemia but a euthyroid state clinically. To date, 23 inactivating mutations of the TSH receptor (TSHR) gene have been proven responsible for the clinical condition, but an absence of mutations in the TSHR gene has been reported for several cases of TSH resistance as well. In this paper, we aimed to investigate the actual role of the TSHR gene in the development of both subclinical and congenital hypothyroidism.

Functional studies of new TSH receptor (TSHr) mutations identified in patients affected by hypothyroidism or isolated hyperthyrotrophinaemia.

Objectives  To establish the role of new TSH receptor (TSHr) variants (P27T, E34 K, R46P, D403N, W488R and M527T) recently identified in children with congenital hypothyroidism (CH) or subclinical hypothyroidism (SH) with a thyroid gland of normal size.

Neonatal Screening for Congenital Adrenal Hyperplasia in North-Eastern Italy: A Report Three Years into the Program

Aims: To evaluate the incidence of congenital adrenal hyperplasia (CAH) in the Northern Italian population and the efficiency of the North-Eastern Italy screening program. To adjust cut-off levels for 17-hydroxyprogesterone (17-OHP) in relation to gestational age and birth weight, comparing the benefits in terms of reduction of recall rates with the two approaches and ultimately choosing the better of the two. Subjects and Methods: Since September 2001, blood samples from neonates born in North-Eastern Italy have been screened with a fluoroimmunoassay method for 17-OHP determination (DELFIA). A preliminary cut-off level of ≧30 nmol/l was set both for term and preterm newborns. The values of 17-OHP were analysed usingstatistical methods in relation to gestational age and birth weight in order to modify the cut-off on the basis of our data. Results: After 33 months of screening we screened 128,282 newborns and detected 6 affected babies. During the first 8 months of screening among the recalled babies, 89.6 and 78.1% were preterm and low-birth-weight newborns, respectively, with a recall rate of 2.59% for premature neonates and of 4.94% for babies with birth weights <2,500 g. We chose a new cut-off value of 50 nmol/l for preterm newborns only and, after 4 months, the recall rate was reduced to 0.83% for these infantsand to 1.83% for low-birth-weight infants. Conclusion: After 33 months of screening for CAH in North-Eastern Italy, we report an incidence of 1:21,380. In 5 out of 6 affected babies, the diagnosis was established only after a positive screening test, which prevented a severe salt-wasting crisis in these babies. The cut-off level related to gestational age led to a significant reduction in the number of false-positives among preterm babies.We therefore intend to continue with the screening program for CAH in North-Eastern Italy, keeping a gestational-age-related cut-off in the hope that our data may encourage a national screening program for CAH.

Prepubertal serum inhibin B in cryptorchid infants and in monorchid boys with compensatory testicular hypertrophy

OBJECTIVE To investigate the prepubertal serum inhibin B levels in monorchid boys with compensatory testicular hypertrophy (CTH) and in surgically treated cryptorchid boys with normal testicular volume. DESIGN Prospective study. SETTING Pediatric Division, University of Verona, Italy. PATIENT(S) Thirty-two prepubertal boys: 11 monorchids with CTH and 21 cryptorchids. For comparison we analyzed 15 healthy boys. MAIN OUTCOME MEASURE(S) All patients underwent a GnRH agonist test. Inhibin B measurement was performed at basal time. RESULT(S) There was a significant difference in mean testicular volume between monorchid and cryptorchid or healthy children, with boys with CTH evidencing larger testicle volume. There was no significant difference in inhibin B levels between boys with CTH and cryptorchid, but the levels were significantly lower in both groups than in the control group. Boys with CTH had significantly higher serum levels of basal FSH than children with cryptorchid. The FSH peak response to GnRH agonist stimulation was significantly higher in boys with CTH than in those with cryptorchid. CONCLUSION(S) Monorchid infants with CTH showed low inhibin B and high FSH levels. Our finding may confirm the hypothesis that CTH is unable to prevent testicular insufficiency in adulthood. We suggest an early hormonal evaluation of boys with CTH at puberty, together with early sperm analysis.

Congenital hypothyroidism with delayed TSH elevation in low-birth-weight infants: incidence, diagnosis and management

OBJECTIVE To evaluate the incidence of congenital hypothyroidism (CH) with delayed TSH elevation among low-birth-weight (LBW) newborns in North-Eastern Italy and to verify if they need a second or third screening. DESIGN Analysis of clinical and biochemical data of newborns affected by CH with delayed TSH elevation identified by neonatal screening. METHODS Data of all newborns with birth weight (BW) <2500 g and evidence of delayed TSH elevation at newborn screening were collected between 2011 and 2014. Confirmatory tests were based on serum TSH and FT4 levels. All their clinical signs at diagnosis were reported. RESULTS 57.5% of LBW newborns with delayed TSH increase at neonatal screening presented a CH with delayed TSH elevation and began a treatment with l-thyroxine. The incidence of this condition in North-Eastern Italy is therefore 1:908. The remaining infants presented a subclinical hypothyroidism (21.25%) or a complete normal serum thyroid function (21.25%). These data could be drawn only from a retesting strategy of neonatal screening. CONCLUSIONS Our report describes the incidence of CH with delayed TSH rise in North-Eastern Italy and differentiates this clinical condition from other thyroid dysfunctions of preterm or LBW newborns. The second-screening strategy for CH in neonates with BW < 2500 g proved useful in detecting newborns who otherwise would not be identified at the first screening.

Lack of association between thyrotropin receptor gene polymorphisms and subclinical hypothyroidism in children.

Subclinical hypothyroidism is defined as a serum TSH level above the statistically set reference range, associated to normal free thyroid hormone concentrations. Genetic and environmental factors contribute to the inter- and intra-individual biological variations of TSH levels, sometimes leading to uncertainty of treatment in the clinical practice, especially when moderate elevations above the upper limit of the reference range are considered (5< TSH <10 mIU/l). In this view, the study of association between subclinical hypothyroidism and possible molecular effectors, such as polymorphisms in the TSH receptor (TSHR) gene, could be interesting. In this paper, we analyzed the TSHR gene polymorphisms in 103 hyperthyrotropinemic infants. A control group of 120 newborns of the same ethnic background was used to evaluate the frequencies of each polymorphism in the population. We found a statistically significant difference in the allelic frequency of the P52T polymorphism, being that the T variant was more represented in the control group (p=0.03). However, no significant results have been obtained in the analysis of the association between genotypes and serum TSH levels. In conclusion, we analyzed 7 polymorphic variants of TSHR gene in subclinical hypothyroidism. The only significant result refers to the allelic frequency of A in the P52T polymorphism, which is statistically reduced when compared with that of a control group.

Implementation of a Congenital Hypothyroidism Newborn Screening Procedure with Mutation Detection on Genomic DNA Extracted from Blood Spots: The Experience of the Italian Northeastern Reference Center

After a couple of decades from the institution of nationwide congenital hypothyroidism (CH) newborn screening program, the first generation properly treated is now displaying normal reproductive rate and the causative molecular defects are spreading from one generation to the next. In the present study we propose a method of detection of mutations in the thyrotropin receptor (TSHR) and in the paired box 8 (PAX8) genes that have been proved to be responsible for some forms of CH. The method, carried out by means of denaturing high-performance liquid chromatography (DHPLC) followed by direct sequencing, takes advantage of the CH newborn screening procedure, because genomic DNA for the analysis is extracted from the same blood spot collected for recall confirmation. Among 16 hypothyroid newborns with thyroid hypoplasia born between January 1999 and April 2005 in northeastern Italy, three heterozygous causative mutations in the TSHR gene were evidenced, whereas the analysis of the PAX8 gene revealed an unknown heterozygous substitution that could interfere with the start of transcription.

A technique of mRNA extraction and labeling from circulating lymphocytes of children treated with growth hormone replacement therapy for microarray analysis

GH replacement therapy exhibits a wide spectrum of response in terms of growth. Nevertheless, standardized doses are still given in clinical practice. In order to optimize the therapy, it is necessary to identify its markers of responsiveness. Given the presence of GH receptors in the circulating lymphocytes, accessible by means of a simple blood withdrawal, blood becomes the tissue of choice as a source of RNA for in vivo gene expression analysis. Hence, the purpose of the present paper is to develop a method of preparation of RNA from lymphocytes suitable for microarray analysis, focusing on the reduction of the blood volume withdrawal in order to perform the analysis on pediatric subjects. After lymphocyte isolation and total RNA extraction from 6 ml of blood, we carried out an amplification procedure preserving the relative abundance of each transcript. Thereafter, we hybridized the labeled amplified RNA on an oligo chip (Human 30K A, MWG-Biotech), but the unsuccessful detection of a good signal to noise ratio indicates that labeled RNA is still insufficient. Therefore, we suggest performing pools of total RNA from different subjects with similar responsiveness to the therapy. It can be speculated that, upon comparison of the obtained data with those derived from pools of controls properly responding to the therapy, specific hallmarks of the condition of low responsiveness, devoid of inter-individual variability, will be evidenced.

3-hydroxyacyl-coenzyme a dehydrogenase deficiency: identification of a new mutation causing hyperinsulinemic hypoketotic hypoglycemia, altered organic acids and acylcarnitines concentrations.

The human HADH gene encodes the short-chain-L-3-hydroxyacyl-CoA dehydrogenase, the enzyme which catalyzes the third step of the β-oxidation of the fatty acids in the mitochondrial matrix. Loss-of-function mutations in the HADH gene lead to short-chain-L-3-hydroxyacyl-CoA dehydrogenase deficiency, an autosomal recessive genetic defect of unknown prevalence with a wide spectrum of phenotypic variability. As in other metabolic diseases, the diagnostic relevance of the biochemical evaluations, plasma acylcarnitines, and urinary organic acids, are crucially dependent on the clinical conditions of the patient during specimen collection.This paper describes the eighth patient carrying a HADH gene mutation, a new homozygous deletion c.565delG leading to an early stop codon (p.V116Wfs124X), in an infant with hyperinsulininemic hypoglycemia, displaying abnormal patterns of plasma acylcarnitines and urinary organic acids. We conclude that, when the residual catalytic activity of the mutated enzyme is seriously reduced, the biochemical hallmarks of the disease, namely plasma 3-hydroxybutyrylcarnitine and urinary 3-hydroxyglutaric acid, are invariably present.