STR mutations on chromosome 15q cause thyrotropin resistance by activating a primate-specific enhancer of MIR7-2/MIR1179.

Thyrotropin (TSH) is the master regulator of thyroid gland growth and function. Resistance to TSH (RTSH) describes conditions with reduced sensitivity to TSH. Dominantly inherited RTSH has been linked to a locus on chromosome 15q, but its genetic basis has remained elusive. Here we show that non-coding mutations in a (TTTG)4 short tandem repeat (STR) underlie dominantly inherited RTSH in all 82 affected participants from 12 unrelated families. The STR is contained in a primate-specific Alu retrotransposon with thyroid-specific cis-regulatory chromatin features. Fiber-seq and RNA-seq studies revealed that the mutant STR activates a thyroid-specific enhancer cluster, leading to haplotype-specific upregulation of the bicistronic MIR7-2/MIR1179 locus 35 kb downstream and overexpression of its microRNA products in the participants' thyrocytes. An imbalance in signaling pathways targeted by these micro-RNAs provides a working model for this cause of RTSH. This finding broadens our current knowledge of genetic defects altering pituitary-thyroid feedback regulation.

Impaired T3 uptake and action in MCT8-deficient cerebral organoids underlie Allan-Herndon-Dudley syndrome.

Patients with mutations in the thyroid hormone (TH) cell transporter monocarboxylate transporter 8 (MCT8) gene develop severe neuropsychomotor retardation known as Allan-Herndon-Dudley syndrome (AHDS). It is assumed that this is caused by a reduction in TH signaling in the developing brain during both intrauterine and postnatal developmental stages, and treatment remains understandably challenging. Given species differences in brain TH transporters and the limitations of studies in mice, we generated cerebral organoids (COs) using human induced pluripotent stem cells (iPSCs) from MCT8-deficient patients. MCT8-deficient COs exhibited (i) altered early neurodevelopment, resulting in smaller neural rosettes with thinner cortical units, (ii) impaired triiodothyronine (T3) transport in developing neural cells, as assessed through deiodinase-3-mediated T3 catabolism, (iii) reduced expression of genes involved in cerebral cortex development, and (iv) reduced T3 inducibility of TH-regulated genes. In contrast, the TH analogs 3,5-diiodothyropropionic acid and 3,3',5-triiodothyroacetic acid triggered normal responses (induction/repression of T3-responsive genes) in MCT8-deficient COs, constituting proof of concept that lack of T3 transport underlies the pathophysiology of AHDS and demonstrating the clinical potential for TH analogs to be used in treating patients with AHDS. MCT8-deficient COs represent a species-specific relevant preclinical model that can be utilized to screen drugs with potential benefits as personalized therapeutics for patients with AHDS.

Effect of the Fetal THRB Genotype on the Placenta.

CONTEXT: Pregnant women with mutations in the thyroid hormone receptor beta (THRB) gene expose their fetuses to high thyroid hormone (TH) levels shown to be detrimental to a normal fetus (NlFe) but not to an affected fetus (AfFe). However, no information is available about differences in placental TH regulators. OBJECTIVE: To investigate whether there are differences in placentas associated with a NlFe compared with an AfFe, we had the unique opportunity to study placentas from 2 pregnancies of the same woman with THRB mutation G307D. One placenta supported a NlFe while the other an AfFe. METHODS: Sections of placentas were collected and frozen at -80 °C after term delivery of a NlFe and an AfFe. Two placentas from healthy women of similar gestational age were also obtained. The fetal origin of the placental tissues was established by gDNA quantitation of genes on the X and Y chromosomes and THRB gene. Expression and enzymatic activity of deiodinases 2 and 3 were measured. Expression of following genes was also quantitated: MCT10, MCT8, LAT1, LAT2, THRB, THRA. RESULTS: The placenta carrying the AfFe exhibited a significant reduction of deiodinase 2 and 3 activities as well as the expression of the TH transporters MCT10, LAT1 and LAT2, and THRA. CONCLUSION: We present the first study of the effect of the fetal THRB genotype on the placenta. Though limited by virtue of the rarity of THRB mutations and sample availability, we show that the fetal THRB genotype influences the levels of TH regulators in the placenta.

Reduction of adverse outcomes from cesarean section by surgical-site infection prevention care bundles in maternity.

OBJECTIVE: To reduce average surgical-site infection (SSI) rates to less than 7.5%, as well as other complications by incrementally implementing an SSI prevention care bundle in maternity: (1) ChloraPrep; (2) PICO dressings, performing elective cesarean sections in a main theater rather than a labor ward and warming blankets; (3) vaginal cleansing; and (4) Hibiscrub. METHODS: In this prospective cohort study, the association between categorical variables was assessed by χ2 tests, temporal trends in the monthly percentage change of SSI were measured using the Joinpoint Regression Program v4.7.0.0. RESULTS: In all, 1682 women (mean age 33.1 ± 5.2 years) underwent either elective (53.9%) or emergency (46.1%) cesarean section. After a small initial increase (10.0%-11.8%), SSI progressively declined to 4.4% (χ2  = 22.1, P < 0.001), as did sepsis, reoperation or readmission for SSI: from 12.5% to 0.5% (χ2  = 90.1, P < 0.001). The rates of SSI fell progressively with the cumulative introduction care bundle components. The average monthly percentage change was -14.0% (95% confidence interval -21.8% to -5.4%, P = 0.004), and the average SSI rate was kept below 7.5% for the last 12 months of the study. CONCLUSION: The maternal SSI prevention care bundle is simple and inexpensive; it effectively reduces SSI after a cesarean section and should be offered routinely to women undergoing cesarean section.

Evaluation of independent risk factors associated with surgical site infections from caesarean section.

BACKGROUND: The present study assessed factors associated with the risk of surgical site infections (SSI) after a caesarean section (C-section). METHODS: Data were collected in 1682 women undergoing elective (53.9%) and emergency (46.1%) C-sections between 1st August 2020, and 30th December 2021, at a National Health Service hospital (Surrey, UK). RESULTS: At the time of C-section, the mean age was 33.1 yr (SD ± 5.2). Compared to women with BMI < 30 kg/m2, those with a BMI ≥ 35 kg/m2 had a greater risk of SSI, OR 4.07 (95%CI 2.48-6.69). Women with a history of smoking had a greater risk of SSI than those who had never smoked, OR 1.69 (95%CI 1.05-2.27). Women with a BMI ≥ 30 kg/m2 and had a smoking history or emergency C-section had 3- to tenfold increases for these adverse outcomes. Ethnic minority, diabetes or previous C-section did not associate with any of the outcomes. CONCLUSIONS: High BMI, smoking, and emergency C-section are independent risk factors for SSI from C-section. Women planning conception should avoid excess body weight and smoking. Women with diabetes and from ethnic minority backgrounds did not have increased risks of SSI, indicating a consistent standard of care for all patients.

Graves' disease and papillary thyroid carcinoma: case report and literature review of a single academic center.

BACKGROUND: Graves' disease (GD) and papillary thyroid cancer (PTC) can be concomitant. The existence of a link between these entities has long been investigated, but a clear correlation hasn't been established. We report a case of GD resistant to medical treatment in which surgery revealed unsuspected PTC and we aim to study the prevalence of PTC in Graves' disease, its clinical characteristics and review of the literature. CASE PRESENTATION: Report of a 32 yo man who presented with weight loss and was found to be biochemically hyperthyroid. Antibodies were positive. Incremental doses of methimazole provided no improvement in thyroid tests. Hypervascularity and a spongiform nodule were noted on ultrasound. Thyroid uptake and scan showed 70.2% uptake. Thyroidectomy was performed due to inadequate therapeutic response. Pathology revealed PTC with extrathyroidal extension and positive lymph nodes. A retrospective review (2000-2021) and literature review of PTC in GD was performed. Clinical data were reviewed. Statistical analysis was calculated to identify correlations. 243 GD patients had total thyroidectomy at an academic center, 50 (20%) had PTC, 14% were microcarcinomas. 76% of cases were less than 55yo, 82% female, 78% stage 1, PTC diagnosis was incidental in 48%, hyperthyroidism was difficult to treat in 10% and only 2% had recurrence of PTC. There was no correlation between demographic or clinical data. CONCLUSIONS: Evidence is controversial with some studies showing GD does not affect PTC prognosis. PTC may not be well recognized in GD, pre-operative assessment should consider risk of cancer.

A Novel Pathogenic Variant in PAX8 Leads to Familial Congenital Hypothyroidism.

We report a 10-month-old girl with familial congenital hypothyroidism harboring a novel heterozygous pathogenic variant in the paired DNA-binding domain of PAX8 (NM_003466:c.110T>C:p.Leu37Pro). Genotype-phenotype correlation revealed complete penetrance of this PAX8 defect in this family, in which the affected father and half-brother carry the same mutation. This deleterious variant has not been reported in any of the available databases [MAFgnomAD = 0, dbSNP (-)], and the amino acid leucine at position 37 is highly conserved across species. Establishing the molecular diagnosis expands our knowledge on the cause of thyroid dysgenesis and provides a guide for counseling and early treatment.

AAV9-MCT8 Delivery at Juvenile Stage Ameliorates Neurological and Behavioral Deficits in a Mouse Model of MCT8-Deficiency.

Background: Allan-Herndon-Dudley syndrome (AHDS) is a severe psychomotor disability disorder that also manifests characteristic abnormal thyroid hormone (TH) levels. AHDS is caused by inactivating mutations in monocarboxylate transporter 8 (MCT8), a specific TH plasma membrane transporter widely expressed in the central nervous system (CNS). MCT8 mutations cause impaired transport of TH across brain barriers, leading to insufficient neural TH supply. There is currently no successful therapy for the neurological symptoms. Earlier work has shown that intravenous (IV), but not intracerebroventricular adeno-associated virus serotype 9 (AAV9) -based gene therapy given to newborn Mct8 knockout (Mct8-/y) male mice increased triiodothyronine (T3) brain content and partially rescued TH-dependent gene expression, suggesting a promising approach to treat this neurological disorder. Methods: The potential of IV delivery of AAV9 carrying human MCT8 was tested in the well-established Mct8-/y/Organic anion-transporting polypeptide 1c1 (Oatp1c1)-/ - double knockout (dKO) mouse model of AHDS, which, unlike Mct8-/y mice, displays both neurological and TH phenotype. Further, as the condition is usually diagnosed during childhood, treatment was given intravenously to P30 mice and psychomotor tests were carried out blindly at P120-P140 after which tissues were collected and analyzed. Results: Systemic IV delivery of AAV9-MCT8 at a juvenile stage led to improved locomotor and cognitive functions at P120-P140, which was accompanied by a near normalization of T3 content and an increased response of positively regulated TH-dependent gene expression in different brain regions examined (thalamus, hippocampus, and parietal cortex). The effects on serum TH concentrations and peripheral tissues were less pronounced, showing only improvement in the serum T3/reverse T3 (rT3) ratio and in liver deiodinase 1 expression. Conclusion: IV administration of AAV9, carrying the human MCT8, to juvenile dKO mice manifesting AHDS has long-term beneficial effects, predominantly on the CNS. This preclinical study indicates that this gene therapy has the potential to ameliorate the devastating neurological symptoms in patients with AHDS.

Severe Resistance to Thyroid Hormone Beta in a Patient with Athyreosis.

We report a patient with congenital hypothyroidism due to athyreosis complicated by a heterozygous thyroid hormone receptor beta (THRß) gene mutation (R320L), resulting in a severe resistance to thyroid hormone beta phenotype. The proband inherited the mutant allele from his father, presenting a very mild phenotype. While the precise reason for this discrepancy remains unknown, we postulate the possibility of de novo mutation and mosaicism in the father. Correlating thyrotropin (TSH) with free thyroxine (fT4) allowed us to predict the amount of fT4 required to normalize the proband's TSH, which supported the treatment with high dose of levothyroxine.

Extended Absorption of Liothyronine from Poly-Zinc-Liothyronine: Results from a Phase 1, Double-Blind, Randomized, and Controlled Study in Humans.

Background: L-triiodothyronine (LT3) has been increasingly used in combination with levothyroxine in the treatment of hypothyroidism. A metal coordinated form of LT3, known as poly-zinc-liothyronine (PZL), avoided in rats the typical triiodothyronine (T3) peak seen after oral administration of LT3. Objectives: To evaluate in healthy volunteers (i) the pharmacokinetics (PK) of PZL-derived T3 after a single dose, (ii) the pharmacodynamics of PZL-derived T3, (iii) incidence of adverse events, and (iv) exploratory analysis of the sleep patterns after LT3, PZL, or placebo (PB) administration. Methods: Twelve healthy volunteers 18-50 years of age were recruited for a Phase 1, double-blind, randomized, single-dose PB-controlled, crossover study to compare PZL against LT3 or PB. Subjects were admitted three separate times to receive a randomly assigned capsule containing PB, 50 µg LT3, or 50 µg PZL, and were observed for 48 hours. A 2-week washout period separated each admission. Results: LT3-derived serum T3 levels exhibited the expected profile, with a Tmax at 2 hours and return to basal levels by 24-36 hours. PZL-derived serum T3 levels exhibited ∼30% lower Cmax that was 1 hour delayed and extended into a plateau that lasted up to 6 hours. This was followed by a lower but much longer plateau; by 24 hours serum T3 levels still exceeded ½ of Cmax. Thyrotropin levels were similarly reduced in both groups. Conclusion: PZL possesses the necessary properties to achieve a much improved T3 PK. PZL is on track to provide hypothyroid patients with stable levels of serum T3.

Association between Cone-Beam Computed Tomography and Histological and Immunohistochemical Features in Periapical Lesions Correlated with Thickened Maxillary Sinus Mucosa.

Background and Objectives: Odontogenic sinusitis is a frequently underestimated pathology with fewer symptoms in patients with periapical lesions, periodontal disease, or iatrogenic foreign bodies in the maxillary sinus. The aim of our study was to determine the correlation between maxillary sinusitis and periapical lesions using cone-beam computed tomography (CBCT) imaging and histological and immunohistochemical investigations. Materials and Methods: A total of 1450 initial patients diagnosed with maxillary sinusitis in the Ear-Nose-Throat (ENT) Department, University of Medicine and Pharmacy "Grigore T. Popa" Iasi, Romania, were treated with anti-inflammatory drugs. Of these, 629 still had unresolved symptomatology and were later referred to the Dental Medicine departments for further investigations. Only 50 subjects with periapical lesions in the premolar/molar maxillary area were included in the present study. All the periapical lesions were observed on CBCT and classified using the Periapical Status Index (PSI) and the mean maxillary sinus mucosa thicknesses (MSMT). The enrolled patients underwent surgical procedures with the excision of periapical lesions. The excised samples were submitted to the histological and immunohistochemical investigations. Results: The 50 patients presented periapical lesions of their maxillary teeth in 328 dental units. There was a higher prevalence of periapical lesions in men than in women (chi-square test). We observed a significant difference between the mean MSMT of individuals with periapical lesions compared to those without (p < 0.01). Mean MSMT was 1.23 mm for teeth without periapical lesions and 3.95 mm for teeth with periapical lesions. The histopathological study identified 50% cases with periapical granulomas, 10% cases with periapical granulomas with cystic potential, and 40% cases as periapical cysts. Immunohistochemical stainings showed that CD4+ helper and CD8+ cytotoxic T lymphocytes, along with CD20+ B lymphocytes and CD68+ macrophages, were diffusely distributed in all periapical cysts and in some periapical granulomas, but CD79α+ plasma cells characterized especially periapical granulomas. Conclusions: The current study observed a significant correlation between CBCT maxillary mucosa thickness and type of periapical lesion. Chronic inflammatory lympho-histiocytic infiltrate predominates in periapical lesions, supporting the idea that lesion progression is determined by a humoral-type (CD20+ and CD79α+ B lymphocytes) but also by a cellular-type (CD4+ and CD8+ T lymphocyte population) immune mechanism.

Dietary Selenium Deficiency Partially Mimics the Metabolic Effects of Arsenic.

Chronic arsenic exposure via drinking water is associated with diabetes in human pop-ulations throughout the world. Arsenic is believed to exert its diabetogenic effects via multiple mechanisms, including alterations to insulin secretion and insulin sensitivity. In the past, acute arsenicosis has been thought to be partially treatable with selenium supplementation, though a potential interaction between selenium and arsenic had not been evaluated under longer-term exposure models. The purpose of the present study was to explore whether selenium status may augment arsenic's effects during chronic arsenic exposure. To test this possibility, mice were exposed to arsenic in their drinking water and provided ad libitum access to either a diet replete with selenium (Control) or deficient in selenium (SelD). Arsenic significantly improved glucose tolerance and decreased insulin secretion and ß-cell function in vivo. Dietary selenium deficiency resulted in similar effects on glucose tolerance and insulin secretion, with significant interactions between arsenic and dietary conditions in select insulin-related parameters. The findings of this study highlight the complexity of arsenic's metabolic effects and suggest that selenium deficiency may interact with arsenic exposure on ß-cell-related physiological parameters.

Novel DIO1 Gene Mutation Acting as Phenotype Modifier for Novel Compound Heterozygous TPO Gene Mutations Causing Congenital Hypothyroidism.

A family with congenital hypothyroidism was identified with two novel deleterious compound heterozygous thyroid peroxidase (TPO) mutations (c.962C>A, and c.1577C>T). Serum thyroid tests showed higher-than-expected serum-free thyroxine (T4) relative to TT3, while reverse triiodothyronine (rT3) was also elevated. Two siblings manifested a more severe phenotype of developmental delay compared with another sibling and were found to harbor an additional novel heterozygous deleterious iodothyronine deiodinase 1 (DIO1) mutation (c.395G>A). In the context of L-T4 replacement, the decreased D1 activity results in abnormal thyroid hormone metabolism with decreased triiodothyronine (T3) generation from L-T4 and may result in decreased T3 bioavailability during critical stages of development.

Human Type 1 Iodothyronine Deiodinase (DIO1) Mutations Cause Abnormal Thyroid Hormone Metabolism.

Background: Iodothyronine deiodinase-1 (D1) selenoenzyme regulates the systemic supply of active thyroid hormone (TH). Transient decrease in D1 enzymatic activity is clinically relevant and adaptive in nonthyroidal illness such as fasting or acute illness. However, DIO1 gene defects have not been reported in humans. Methods: Genetic analysis was performed using whole-exome sequencing in members of two unrelated families presenting with abnormal serum thyroid function tests. Plasmid constructs containing the two pathogenic DIO1 variants were used for in vitro studies assessing the kinetics of their enzymatic activity. Thyroid function tests were measured in Dio1 heterozygous-null mice. Results: We report the novel identification and characterization of two missense DIO1 pathogenic variants (resulting in p.Asn94Lys and p.Met201Ile) in two unrelated families presenting with abnormal TH metabolism with elevated serum reverse triiodothyronine (rT3) levels and rT3/T3 ratios. These characteristic in vivo parameters are also present in Dio1 heterozygous-null mice. Kinetic studies of the resulting mutant D1 proteins demonstrate two- to threefold higher Km indicating lower substrate affinity and slower enzyme velocity. Conclusions: We report the identification and characterization of two missense DIO1 pathogenic variants identified in families with abnormal TH metabolism. This is the first demonstration of inherited D1 deficiency in humans.

Early Diagnosis and Treatment of an Infant with a Novel Thyroid Hormone Receptor α Gene (pC380SfsX9) Mutation.

Resistance to thyroid hormone alpha (RTHα) is caused by mutations in thyroid hormone receptor α (THRA). Little is known about the natural history and treatment of RTHα, and diagnosis before the age of 1 year has not been previously reported. A de novo heterozygous THRA mutation (pC380SfsX9) was identified in a 10-month-old female investigated for developmental delay, hypotonia, macrocephaly, and severe constipation. Treatment with levothyroxine was accompanied by an appropriate rise in thyroxine (T4), triiodothyronine (T3), as well as decrease in thyrotropin levels and in the T3/T4 ratio with a trend toward normalization of peripheral markers of thyroid hormone action. THRA pC380SfsX9 results in extreme RTHα.

Prenatal Treatment of Thyroid Hormone Cell Membrane Transport Defect Caused by MCT8 Gene Mutation.

Background: Mutations of the thyroid hormone (TH)-specific cell membrane transporter, monocarboxylate transporter 8 (MCT8), produce an X-chromosome-linked syndrome of TH deficiency in the brain and excess in peripheral tissues. The clinical consequences include brain hypothyroidism causing severe psychoneuromotor abnormalities (no speech, truncal hypotonia, and spastic quadriplegia) and hypermetabolism (poor weight gain, tachycardia, and increased metabolism, associated with high serum levels of the active TH, T3). Treatment in infancy and childhood with TH analogues that reduce serum triiodothyronine (T3) corrects hypermetabolism, but has no effect on the psychoneuromotor deficits. Studies of brain from a 30-week-old MCT8-deficient embryo indicated that brain abnormalities were already present during fetal life. Methods: A carrier woman with an affected male child (MCT8 A252fs268*), pregnant with a second affected male embryo, elected to carry the pregnancy to term. We treated the fetus with weekly 500 µg intra-amniotic instillation of levothyroxine (LT4) from 18 weeks of gestation until birth at 35 weeks. Thyroxine (T4), T3, and thyrotropin (TSH) were measured in the amniotic fluid and maternal serum. Treatment after birth was continued with LT4 and propylthiouracil. Follow-up included brain magnetic resonance imaging (MRI) and neurodevelopmental evaluation, both compared with the untreated brother. Results: During intrauterine life, T4 and T3 in the amniotic fluid were maintained above threefold to twofold the baseline and TSH was suppressed by 80%, while maternal serum levels remained unchanged. At birth, the infant serum T4 was 14.5 µg/dL and TSH <0.01 mU/L compared with the average in untreated MCT8-deficient infants of 5.1 µg/ and >8 mU/L, respectively. MRI at six months of age showed near-normal brain myelination compared with much reduced in the untreated brother. Neurodevelopmental assessment showed developmental quotients in receptive language and problem-solving, and gross motor and fine motor function ranged from 12 to 25 at 31 months in the treated boy and from 1 to 7 at 58 months in the untreated brother. Conclusions: This is the first demonstration that prenatal treatment improved the neuromotor and neurocognitive function in MCT8 deficiency. Earlier treatment with TH analogues that concentrate in the fetus when given to the mother may further rescue the phenotype.

Clinical and Molecular Analysis in 2 Families With Novel Compound Heterozygous SBP2 (SECISBP2) Mutations.

CONTEXT: Selenocysteine insertion sequence binding protein 2 (SECISBP2, SBP2) is an essential factor for selenoprotein synthesis. Individuals with SBP2 defects have characteristic thyroid function test (TFT) abnormalities resulting from deficiencies in the selenoenzymes deiodinases. Eight families with recessive SBP2 gene mutations have been reported to date. We report 2 families with inherited defect in thyroid hormone metabolism caused by 4 novel compound heterozygous mutations in the SBP2 gene. CASE DESCRIPTIONS: Probands 1 and 2 presented with growth and developmental delay. Both had characteristic TFT with high T4, low T3, high reverse T3, and normal or slightly elevated TSH. The coding region of the SBP2 gene was sequenced and analysis of in vitro translated wild-type and mutant SBP2 proteins was performed. Sequencing of the SBP2 gene identified novel compound heterozygous mutations resulting in mutant SBP2 proteins E679D and R197* in proband 1, and K682Tfs*2 and Q782* in proband 2. In vitro translation of the missense E679D demonstrated all four isoforms, whereas R197* had only 2 shorter isoforms translated from downstream ATGs, and Q782*, K682Tfs*2 expressed isoforms with truncated C-terminus. Reduction in serum glutathione peroxidase enzymatic activity was also demonstrated in both probands. CONCLUSIONS: We report 2 additional families with mutations in the SBP2 gene, a rare inherited condition manifesting global selenoprotein deficiencies. Report of additional families with SBP2 deficiency and their evaluation over time is needed to determine the full spectrum of clinical manifestations in SBP2 deficiency and increase our understanding of the role played by SBP2 and selenoproteins in health and disease.

Nonautoimmune Hyperthyroidism Caused by a Somatic Mosaic GNAS Mutation Involving Part of the Thyroid Gland.

Nonautoimmune hyperthyroidism caused by activating mutations in the GNAS gene is a rare condition. In this study, we report a five-year-old girl diagnosed with nonautoimmune hyperthyroidism and tall stature harboring a somatic mosaic gain-of-function mutation in the GNAS gene (NM_080425.3: c.2530C>T;p.Arg844Cys previously reported as NM_000516.5:c.601C>T;p.Arg201Cys) and referred to thereafter as R201C, in three of four quadrants of the thyroid gland. Provision of a molecular diagnosis may avoid unnecessary complete ablation of the thyroid gland.