Functional variants in a TTTG microsatellite on 15q26.1 cause familial nonautoimmune thyroid abnormalities.

Insufficient thyroid hormone production in newborns is referred to as congenital hypothyroidism. Multinodular goiter (MNG), characterized by an enlarged thyroid gland with multiple nodules, is usually seen in adults and is recognized as a separate disorder from congenital hypothyroidism. Here we performed a linkage analysis of a family with both nongoitrous congenital hypothyroidism and MNG and identified a signal at 15q26.1. Follow-up analyses with whole-genome sequencing and genetic screening in congenital hypothyroidism and MNG cohorts showed that changes in a noncoding TTTG microsatellite on 15q26.1 were frequently observed in congenital hypothyroidism (137 in 989) and MNG (3 in 33) compared with controls (3 in 38,722). Characterization of the noncoding variants with epigenomic data and in vitro experiments suggested that the microsatellite is located in a thyroid-specific transcriptional repressor, and its activity is disrupted by the variants. Collectively, we presented genetic evidence linking nongoitrous congenital hypothyroidism and MNG, providing unique insights into thyroid abnormalities.

DHX37 Variant is One of Common Genetic Causes in Japanese Patients with Testicular Regression Syndrome / Partial Gonadal Dysgenesis without Müllerian Derivatives.

INTRODUCTION: The testicular regression syndrome (TRS) is a form of differences of sex development (DSD) in which the testes differentiate and function during early embryonic development, but subsequently regress. The clinical phenotype of TRS often overlaps with that of partial gonadal dysgenesis (PGD). Previous studies have demonstrated a causal association between TRS/PGD and heterozygous missense variants of DHX37. METHODS: We enrolled 11 Japanese 46,XY individuals (from 10 families) with TRS/PGD who exhibited undetected or hypoplastic testes, Müllerian duct regression, and low serum testosterone or anti-Müllerian hormone levels. The subjects underwent targeted sequencing of 36 known causative genes for DSD, PCR-based Sanger sequencing of DHX37, or whole exome sequencing. RESULTS: Previously described pathogenic variants or novel nonsense variants (SRY, NR5A1, and DMRT1) were observed in four out of 10 families. Additionally, we identified two heterozygous rare variants of DHX37 in four families: a previously reported pathogenic variant (c.923G>A, p.Arg308Gln) in three and a novel likely pathogenic variant (c.1882A>C, p.Thr628Pro) in one. The external genitalia of patients with the DHX37 variants varied from female-type to male-type without micropenis. Eighty percent of Japanese patients with TRS/PGD had monogenic disorders including DHX37 variant being the most commonly identified (40%). The external or internal genital phenotype of TRS/PGD overlaps between DHX37 variant carriers and others. CONCLUSIONS: DHX37 variant is one of common genetic causes in Japanese patients with TRS/PGD without Müllerian derivatives. Genetic test is helpful in detecting DHX37-related TRS/PGD, because of the phenotypic diversity of the external genitalia in this disorder.

Genotype-Phenotype Correlations in Thirty Japanese Patients with Congenital Hypothyroidism Attributable to TG Defects.

CONTEXT: Thyroglobulin (Tg), encoded by TG, is essential for thyroid hormone synthesis. TG defects result in congenital hypothyroidism (CH). Most reported patients were born before the introduction of newborn screening (NBS). OBJECTIVE: We aimed to clarify the phenotypic features of patients with TG defects diagnosed and treated since the neonatal period. SUBJECTS AND METHODS: We screened 1061 patients with CH for thirteen CH-related genes and identified thirty patients with TG defects. One patient was diagnosed due to hypothyroidism-related symptoms and the rest were diagnosed via NBS. Patients were divided into two groups according to their genotypes, and clinical characteristics were compared. We evaluated the functionality of the seven missense variants using HEK293 cells. RESULTS: Twenty-seven rare TG variants were detected, including fifteen nonsense, three frameshift, two splice-site, and seven missense variants. Patients were divided into two groups: thirteen patients with biallelic truncating variants and seventeen patients with monoallelic/biallelic missense variants. Patients with missense variants were more likely to develop thyroid enlargement with TSH stimulation than patients with biallelic truncating variants. Patients with biallelic truncating variants invariably required full hormone replacement, whereas patients with missense variants required variable doses of levothyroxine. Loss of function of the seven missense variants was confirmed in vitro. CONCLUSION: To our knowledge, this is the largest investigation on the clinical presentation of TG defects diagnosed in the neonatal period. Patients with missense variants showed relatively mild hypothyroidism with compensative goiter. Patients with only truncating variants showed minimal or no compensative goiter and required full hormone replacement.

Two Japanese Infants With Hypothyroidism Following Exposure to Iodinated Contrast Media.

We report 2 Japanese infants with hypothyroidism requiring levothyroxine (LT4) replacement therapy following exposure to iodinated contrast media (ICM). Patient 1 was born at 32 weeks gestation. He had congenital heart disease and underwent contrast-enhanced computed tomography (CT) on day 22 (estimated amount of iodine: 600 mg/kg/dose). The newborn mass screening showed normal thyrotropin (thyroid-stimulating hormone; TSH) levels at day 4, but high TSH and low free thyroxine levels on retest at day 44. LT4 replacement therapy was administered on days 46 to 74. No hypothyroidism requiring LT4 replacement therapy was observed afterward. The ultrasonography showed a hypoplastic thyroid gland. Patient 2 was born full-term. She had congenital heart disease and underwent contrast-enhanced CT on day 52 (estimated amount of iodine: 1500 mg/kg/dose). The newborn mass screening showed normal TSH levels on day 4, but high TSH levels on retest on day 62. LT4 replacement therapy was administered from day 65 to 3 years of age. Genetic analysis showed a heterozygous variant of DUOX2. Exposure to ICM can result in hypothyroidism, requiring LT4 replacement therapy. The severity of hypothyroidism may depend on risk factors, such as genetic predisposition, preterm birth, thyroid hypoplasia, or early exposure to ICM.

Utility of basal and peak TSH values in TRH stimulation testing for predicting the long-term therapeutic prognosis of primary congenital hypothyroidism.

In Japan, most neonates undergo screening for congenital hypothyroidism (CH). A TRH stimulation test (TRH-T) may be performed after initial treatment as a useful method for reevaluating the patient's thyroid status. However, no studies have compared basal and peak TSH values in TRH-T in patients with long-term follow-up. This was a retrospective and observational study. The inclusion criteria were as follows: (1) CH diagnosis based on positive newborn screening, (2) follow-up > 15 yr, and (3) TRH-T after LT4 discontinuation. The participants were divided into a no-treatment group (No-T group) and a treatment group (T group). The No-T and T groups included 14 and nine patients, respectively. The age at TRH-T was 5.38 yr for the No-T group and 4.25 yr for the T group, with no significant difference. The basal and peak TSH levels were significantly lower in the No-T group. The areas under the Receiver operating characteristic curve for basal and peak TSH values were 0.984 and 0.905, respectively. When the basal TSH level was under 4.594 IU/mL, the No-T group had a sensitivity of 1.00 and a specificity of 0.93. Basal TSH levels alone may be sufficient for predicting the long-term therapeutic prognosis of patients with CH.

A case of 46,XY complete gonadal dysgenesis with a novel missense variant in SRY.

Disorders of sex development (DSD) with mild external genital abnormalities may be diagnosed after puberty. Here, we report a case of 46,XY complete gonadal dysgenesis with a novel missense variant in sex-determining region Y (SRY), diagnosed after primary amenorrhea. A 15-yr-old patient presented to our gynecology department with a chief complaint of amenorrhea. The patient was diagnosed with a 46,XY karyotype, and SRY gene positivity. Gonadotropin levels were high, whereas testosterone levels were low. A pelvic magnetic resonance imaging (MRI) revealed a hypoplastic uterus; however, no gonads could be identified. Laparoscopy revealed bilateral streak gonads, fallopian tube-like structures, and the uterus. The gonads were removed based on the risk of gonadal malignancy. Comprehensive genetic analysis of DSD revealed a previously unreported SRY variant, c.271A>T, p.Ser91Cys, and in silico analysis predicted the variant to be pathogenic. The patient was diagnosed with 46,XY complete gonadal dysgenesis with a novel missense variant in SRY. The patient continued female hormone replacement therapy and experienced breast enlargement and cyclic menstruation. Determining the etiology of DSD can be difficult, causing anxiety in patients and their families. In addition to surgical scrutiny, genetic analysis is important to aid in diagnosis and reassure patients and their families.

Knowns and unknowns about congenital hypothyroidism: 2022 update.

Several excellent guidelines and expert opinions on congenital hypothyroidism (CH) are currently available. Nonetheless, these guidelines do not address several issues related to CH in detail. In this review, the authors chose the following seven clinical issues that they felt were especially deserving of closer scrutiny in the hope that drawing attention to them through discussion would help pediatric endocrinologists and promote further interest in the treatment of CH. 1. How high should the levothyroxine (L-T4) dose be for initial treatment of severe and permanent CH? 2. What is the optimal method for monitoring treatment of severe CH? 3. At what level does maternal iodine intake during pregnancy affect fetal and neonatal thyroid function? 4. Does serum thyroglobulin differ between patients with a dual oxidase 2 (DUOX2) variants and those with excess iodine? 5. Who qualifies for a genetic diagnosis? 6. What is the best index for distinguishing transient and permanent CH? 7. Is there any cancer risk associated with CH? The authors discussed these topics and jointly edited the manuscript to improve the understanding of CH and related issues.

Higher serum thyroid autoantibody value is a risk factor of hypothyroidism in children and young adults with chronic thyroiditis.

Thyroid function in patients with chronic thyroiditis (CT) varies depending on the clinical course. Serum antithyroglobulin antibody (TgAb) and antithyroid peroxidase antibody (TPOAb) levels may be used to predict hypothyroidism in CT. In this retrospective cohort study, patients with CT, defined as having a high TgAb or TPOAb value, were divided into a hypothyroid group (HG) and euthyroid group (EG), after a mean follow-up of 2.5 years. The definitions of the two groups was based on the maximum TSH value from the initial measurement to the most recent follow-up: HG was defined as TSH 10.0 µIU/mL or higher, and EG was defined as TSH < 10.0 µIU/mL. There were 20 and 113 patients in the HG and EG, respectively. There were no significant differences in age, sex, underlying diseases, or TgAb and TPOAb levels between the groups. Receiver operating characteristic curve analyses of TgAb and TPOAb values for predicting thyroid function showed areas under the curve of 0.714 and 0.757, respectively. The value with the highest diagnostic accuracy was 106 IU/mL for TgAb and 16 IU/mL for TPOAb. Thus, TgAb > 106 IU/mL and TPOAb > 16 IU/mL may predict hypothyroidism in children and young adults with CT.

Status Epilepticus due to Asfotase Alfa Interruption in Perinatal Severe Hypophosphatasia.

BACKGROUND: Hypophosphatasia (HPP), an inherited, metabolic disorder caused by loss-of-function mutations in the ALPL gene, affects not only bone and tooth mineralization but also central nervous system (CNS) function, resulting in vitamin B6/pyridoxine-responsive seizures. Asfotase alfa treatment mainly improves the skeletal manifestations of HPP. As of yet, there are no reports demonstrating seizure exacerbation caused by asfotase alfa interruption. CASE: The patient was a 2-year and 8-month-old female with clinical and genetic diagnosis of perinatal severe HPP. Genetic analysis of ALPL identified compound heterozygous variants. Asfotase alfa and pyridoxine administration begun on postnatal day 2 restored normal development and suppressed seizures except for simple febrile seizures. From age 2 years when her asfotase alfa injections became irregular, she began experiencing seizure exacerbation, including status epilepticus, leading to acute encephalopathy and severe sequelae. The seizure exacerbations always coincided with low alkaline phosphatase (ALP) activity caused by the interruption of asfotase alfa administration. DISCUSSION: The clinical course of the present case demonstrated the effect of asfotase alfa on CNS symptoms and a clear correlation between low serum ALP activity and seizure exacerbation. Serum ALP activity measurements were useful as a therapeutic marker in the present case. Furthermore, the risk of seizure exacerbation in the patient could have been predicted, given the genotype-phenotype correlation related to the ALPL gene in the Japanese population. CONCLUSION: Regular asfotase alfa injections are needed to prevent seizure exacerbation in patients with HPP. Educating patients and their family about the need for regular asfotase alfa treatment is crucial to preventing disease exacerbation.

Levothyroxine Dosage as Predictor of Permanent and Transient Congenital Hypothyroidism: A Multicenter Retrospective Study in Japan.

BACKGROUND: Congenital hypothyroidism (CH) can be divided into 2 types, transient CH (T-CH) and permanent CH (P-CH), depending on the requirement of levothyroxine (LT4) for life-long treatment. Several studies have recently reported that the LT4 dosage is useful for predicting the LT4 requirement, but none of the studies followed their patients to puberty. OBJECTIVE: To determine the cutoff value for the LT4 dosage as a predictor of the LT4 requirement after puberty in patients with CH. METHODS: The LT4 dosage and clinical data on 99 patients with CH who were followed at the participating hospitals from the neonatal period to 15 years of age or older were retrospectively analyzed. Based on their LT4 requirement at their last hospital visit, the participants were divided into the P-CH group (n = 75), who were treated with LT4, and the T-CH group (n = 24), who were not. RESULTS: At age 1 year, a higher LT4 dosage was required for the P-CH group (median 3.75 vs. 2.88 µg/kg/day; p < 0.001). When the LT4 dosage cutoff value at age 1 year was set at 4.79 and 1.74 µg/kg/day, the specificity of P-CH and T-CH (for denying T-CH and P-CH, respectively) was 100 and 97%, respectively. CONCLUSIONS: An LT4 dosage above 4.7 µg/kg/day and below 1.8 µg/kg/day at age 1 year may help predict P-CH and T-CH, respectively.

Treatment of adrenal crisis in patients with primary hypoadrenalism can lead to hypertension.

Hypertension is one of the most serious side effects of glucocorticoid therapy. We retrospectively investigated the frequency of hypertension during treatment of adrenal crisis and analyzed the factors associated with its development. Patients who were admitted for primary hypoadrenalism due to diagnosed or suspected adrenal crisis were included. In the analysis, the subjects were divided into two groups: the hypertensive group (group H) and non-hypertensive group (group Non-H). The primary endpoint was the difference in the hourly therapeutic hydrocortisone (HDC) dosage between the two groups. The hourly therapeutic HDC dose in the two groups was defined as the hourly HDC dose from the start of HDC infusion until the development of hypertension in group H or until the last blood pressure measurement in group Non-H. Nine of 19 crises led to hypertension. There was no significant difference in the therapeutic HDC dosage between the groups (p = 0.108). In conclusion, hypertension developed in some patients during treatment for adrenal crisis. There was no significant difference in the therapeutic HDC dosage between groups H and Non-H.

Rapid Growth and Early Metastasis of Papillary Thyroid Carcinoma in an Adolescent Girl with Graves' Disease.

BACKGROUND: The risk factors for rapid growth and early metastasis of papillary thyroid carcinoma (PTC) and the role of coexisting Graves' disease in the clinical course of PTC remain uncertain in children. CASE DESCRIPTION: We report on a Japanese girl, whose PTC rapidly grew and metastasized within 4 years. Graves' disease was diagnosed by the presence of serum TSH receptor antibodies at 8 years of age when thyroid ultrasonography detected no nodules. After 4 years of effective treatment with thiamazole, multifocal nodules - up to 47 mm in diameter - were detected on thyroid ultrasonography. Chest CT scan revealed multiple metastatic lesions in the lung. After total thyroidectomy, PTC was pathologically diagnosed. The patient underwent two courses of radioactive iodine (RAI) treatment, but the pulmonary metastatic lesions did not take up the RAI. Molecular analyses of the PTC tissue identified a TFG/NTRK1 chimeric gene and disclosed the preserved expression of TSHR and the reduced expression of SLC5A5 compared with non-tumor thyroid tissue. CONCLUSIONS: Rapid growth and early metastasis of PTC with coexisting Graves' disease in this patient can be related to a combination of multiple factors including preserved TSHR expression, reduced SLC5A5 expression, and TFG/NTRK1 rearrangement.

Identification of a biosynthetic gene cluster in rice for momilactones.

Rice diterpenoid phytoalexins such as momilactones and phytocassanes are produced in suspension-cultured rice cells treated with a chitin oligosaccharide elicitor and in rice leaves irradiated with UV light. The common substrate geranylgeranyl diphosphate is converted into diterpene hydrocarbon precursors via a two-step sequential cyclization and then into the bioactive phytoalexins via several oxidation steps. It has been suggested that microsomal cytochrome P-450 monooxygenases (P-450s) are involved in the downstream oxidation of the diterpene hydrocarbons leading to the phytoalexins and that a dehydrogenase is involved in momilactone biosynthesis. However, none of the enzymes involved in the downstream oxidation of the diterpene hydrocarbons have been identified. In this study, we found that a putative dehydrogenase gene (AK103462) and two functionally unknown P-450 genes (CYP99A2 and CYP99A3) form a chitin oligosaccharide elicitor- and UV-inducible gene cluster, together with OsKS4 and OsCyc1, the diterpene cyclase genes involved in momilactone biosynthesis. Functional analysis by heterologous expression in Escherichia coli followed by enzyme assays demonstrated that the AK103462 protein catalyzes the conversion of 3beta-hydroxy-9betaH-pimara-7,15-dien-19,6beta-olide into momilactone A. The double knockdown of CYP99A2 and CYP99A3 specifically suppressed the elicitor-inducible production of momilactones, strongly suggesting that CYP99A2, CYP99A3, or both are involved in momilactone biosynthesis. These results provide strong evidence for the presence on chromosome 4 of a gene cluster involved in momilactone biosynthesis.