Usefulness of thyroid function assessment in infants born to mothers with thyroid dysfunction during pregnancy

Introduction

Maternal thyroid disease is considered as a risk factor for abnormal thyroid function at birth, as well as for long-term morbidity in offspring. The potential harmful effects on the neonate had led to the clinical practice of thyroid function assessment in infants born to mothers with thyroid disease during pregnancy. In this study, we evaluated the usefulness of routine thyroid function tests for every newborn of a mother with thyroid dysfunction.

Methods

Data were collected retrospectively from the medical files of mothers diagnosed with thyroid disease and their infants (496 mother-neonate pairs). All mothers with diagnosed thyroid disease who gave birth in the years 2016-2019 at our medical center were included.

Results

Hypothyroidism was the most common maternal diagnosis (91.4%), among which 48.7% had Hashimoto's thyroiditis. Hyperthyroidism was diagnosed in 8.6% of the cohort - 71.6% of them with Graves' disease. None of the newborns was diagnosed with congenital hypothyroidism in the screening program. Thyroid-stimulating hormone was >10 mIU/L in 14.6% and >20 mUI/L in 2.2%; all had free thyroxine within normal range. Serum thyroid function test identified four infants with thyroid disease; two had congenital hypothyroidism not related to maternal thyroid disease, one had transient familial congenital hypothyroidism and one had neonatal Graves' disease.

Conclusions

Thyroid function testing for all newborns of mothers with thyroid dysfunction seems redundant. However, in cases of congenital hypothyroidism in siblings, thyroid function test, in addition to newborn thyroid screening, is recommended, and more careful follow-up is indicated. In maternal Graves' disease, thyroid function test on days 2-3 of life is recommended.

OR15-07 Novel Genes Involved in Sex Differentiation Identified by Whole-Exome Sequencing in a Cohort of Children with Disorders of Sex Development

Background: Disorders of sex development (DSD) are classified as a congenital discrepancy between external genitalia, gonadal and chromosomal sex. Despite extensive laboratory and imaging investigations, the etiology of DSD is unknown in more than 50% of patients and the diagnosis is often delayed to the second decade of life. Our objective was to evaluate the etiology of DSD by whole-exome sequencing (WES) in children in whom hormonal and candidate gene approaches had not identified the etiology. Methods: Nine patients diagnosed with DSD (eight 46,XY and one 46,XX) were enrolled. Patients underwent hormonal evaluation, including ACTH, GnRH and hCG tests. Candidate genes were sequenced in accordance with the hormonal results. WES was performed for the probands and their parents. Results: The eight 46,XY patients presented with micropenis, cryptorchidism and hypospadias at birth and the 46,XX patient with fusion of the labia majora. In six of the nine patients (66%), a pathogenic mutation was identified by WES that explained the phenotype: four known DSD-causing genes—POR, CHD7, HSD17B3 and WT1—and two novel genes—BMP4 and RFXP2. In three patients, variants of unknown significance were found. An 11-y-old boy had a novel de-novo mutation in BMP4. In humans, mutations in this gene, encoding bone morphogenetic protein 4, are associated with autosomal dominant microphthalmia. BMP4 is expressed in the urethral epithelium and has a role in the development of external genitalia and the pituitary. This is the first report of a BMP4 mutation in a child with DSD. A 12-y-old boy had a mutation in RFXP2, encoding insulin-like 3 hormone receptor, which has been previously reported in adult males with cryptorchidism. This is the first case of an RFXP2 mutation in a child with DSD. Conclusions: WES has a crucial role in early diagnosis of the etiology of DSD, making extensive endocrine testing unnecessary, and has important implications for sex of rearing decisions.

Increase in the incidence of type 1 diabetes in Israeli children following the Second Lebanon War

BACKGROUND

Type 1 diabetes is an autoimmune disease occurring in genetically susceptible individuals. The precipitating cause is unclear. Recently, the Second Lebanon War exposed a large civilian population in northern Israel to significant psychological stress in the form of repeated barrages of missile attacks.

HYPOTHESIS

We hypothesized that trends in regional incidence of type 1 diabetes before and after the war would reflect an association with stress.

METHODS

All type 1 diabetes patients aged 0-17 yr who were reported to the Israel Juvenile Diabetes Register (n = 1822) in the four pre-war (2002-2005) and two post-war years (2006-2007) were included in the study. The patients were stratified by gender, age, ethnicity, family history of type 1 diabetes, season at diagnosis, and region of residency, namely, those who lived in the northern regions that were attacked and those in other regions.

RESULTS

The post-war incidence of type 1 diabetes was increased in the northern regions (rate ratio, RR = 1.27; p = 0.037), with no change in the other regions. This change was more prominent in males (RR = 1.55; p = 0.005) but similar in summer and winter, in different ages, and in different ethnic groups. There was no change in the proportion of new patients with a family history of the disease.

CONCLUSIONS

For the first time in a large population, we found a positive association between the trauma of war and an increase in the incidence of type 1 diabetes in children and adolescents. The increase in incidence was not associated with genetic susceptibility to the disease.

Minimal Invasive Follicular Thyroid Carcinoma Developed in Dyshormonogenetic Multinodular Goiter Due to Thyroid Peroxidase Gene Mutation

Background: The occurrence of thyroid carcinoma in patients with congenital hypothyroidism (CH) caused by dyshormonogenesis is very rare, and has been reported in only one patient harboring mutations in the thyroid peroxidase (TPO) gene. Patient findings: We report on a 29-year follow-up of two consanguineous siblings with CH due to total iodide organification defect who also had sensorineural hearing loss. Molecular analysis revealed a novel biallelic mutation of the TPO gene in which phenylalanine substitutes serine at codon 292 (c.875C>T, p.S292F) in exon 8. Despite early initiation, adequate doses of L-thyroxine treatment and consequently normal TSH levels, the proposita developed a huge multinodular goiter (MNG) and underwent total thyroidectomy due to tracheal compression. Pathological examination revealed a unifocal follicular thyroid carcinoma without vascular invasion in the left lobe of the thyroid gland. Summary: Our finding of follicular thyroid carcinoma arising from dyshormonogenetic MNG in a patient without elevated serum TSH levels indicates that genetic and environmental factors other than TSH level might be involved in the development of thyroid carcinoma in dyshormonogenetic MNG. Conclusions: Despite the rare occurrence of thyroid carcinoma in dyshormonogenetic MNG, we recommend long-term follow-up and regular neck ultrasound imaging to prevent delayed diagnosis of thyroid carcinoma.