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Objective Transient neonatal diabetes mellitus (TNDM) is caused by activating mutations in ABCC8 and KCNJ11 genes (KATP/TNDM) or by chromosome 6q24 abnormalities (6q24/TNDM). We wanted to assess whether these different genetic aetiologies result in distinct clinical features. Design Retrospective analysis of the Italian data set of patients with TNDM. Methods Clinical features and treatment of 22 KATP/TNDM patients and 12 6q24/TNDM patients were compared. Results Fourteen KATP/TNDM probands had a carrier parent with abnormal glucose values, four patients with 6q24 showed macroglossia and/or umbilical hernia. Median age at diabetes onset and birth weight were lower in patients with 6q24 (1 week; −2.27 SD) than those with KATP mutations (4.0 weeks; −1.04 SD) (P = 0.009 and P = 0.007, respectively). Median time to remission was longer in KATP/TNDM than 6q24/TNDM (21.5 weeks vs 12 weeks) (P = 0.002). Two KATP/TNDM patients entered diabetes remission without pharmacological therapy. A proband with the ABCC8/L225P variant previously associated with permanent neonatal diabetes entered 7-year long remission after 1 year of sulfonylurea therapy. Seven diabetic individuals with KATP mutations were successfully treated with sulfonylurea monotherapy; four cases with relapsing 6q24/TNDM were treated with insulin, metformin or combination therapy. Conclusions If TNDM is suspected, KATP genes should be analyzed first with the exception of patients with macroglossia and/or umbilical hernia. Remission of diabetes without pharmacological therapy should not preclude genetic analysis. Early treatment with sulfonylurea may induce long-lasting remission of diabetes in patients with KATP mutations associated with PNDM. Adult patients carrying KATP/TNDM mutations respond favourably to sulfonylurea monotherapy.

CONTEXT: Mutations in the DUOX2 gene have been associated with transient or permanent congenital hypothyroidism due to a dyshormonogenic defect. OBJECTIVE: This study aimed to verify the prevalence of DUOX2 mutations and the associated clinical features in children selected by criteria supporting a partial iodide organification defect (PIOD). PATIENTS AND METHODS: Thirty children with PIOD-like criteria were enrolled and genotyped. A detailed clinical characterization was undertaken together with the functional analysis of the DUOX2 variations and the revision of the clinical and molecular data of the literature. RESULTS: In this large selected series, the prevalence of the DUOX2 mutations was high (37%). We identified 12 missense variants, one splice site, and three frameshift DUOX2 mutations. Functional analyses showed significant impairment of H2O2 generation with five missense variants. Stop-codon mutants were shown to totally abolish DUOX2 activity by nonsense-mediated RNA decay, exon skipping, or protein truncation. DUOX2 mutations, either mono- or biallelic, were most frequently associated with permanent congenital hypothyroidism. Moreover, the present data suggested that, together with goiter and PIOD, the most significant features to select patients for the DUOX2 analysis are the low free T4 and the high TSH concentrations at the first postnatal serum sampling, despite borderline blood spot TSH. Interestingly, the analysis of previously described DUOX2 mutated cases confirmed the validity of these findings. CONCLUSIONS: The defects in the peroxide generation system are common among congenital hypothyroidism patients with PIOD. The most robust clinical parameters for selecting patients for DUOX2 analysis have been identified, and several DUOX2 variants have been functionally characterized.

Context: In recent years changes in screening strategies for congenital hypothyroidism (CH) led to an increased detection of mild forms of CH, associated with eutopic thyroid gland. Objectives: We aimed to determine the clinical evolution of CH with eutopic thyroid gland and to find out prognostic factors at diagnosis and follow-up. Patients and Methods: We retrospectively analyzed agroup of84 children withCH andeutopic thyroid gland treated at our institution. They all underwent clinical re-evaluation after the age of 3, based on thyroid function testing after L-thyroxine therapy withdrawal, thyroid ultrasonography, and 123I scintigraphy with perchlorate discharge test. Genetic analysis was performed in selected cases. Results: At re-evaluation, 34.5% of patients showed permanent hypothyroidism and needed L-thyroxine reintroduction, 27.4% had persistent hyperthyrotropinemia (TSH5-10mU/L), and 38.1% had transient hypothyroidism. Major risk factors for permanent CH were prematurity, first-degree familial history of goiter/nodules, thyroid hypoplasia at diagnosis, and high L-thyroxine requirements at follow-up. Iodine organification defects were found in 29.7% of patients, 30% of whom harbored DUOX2 mutations. TSH receptor gene mutations were found in 8.7% of patients with persistent thyroid dysfunction and negative perchlorate discharge test. Conclusions: Only one-third of patients with CH and eutopic thyroid gland needed to continue L-thyroxine therapy after re-evaluation. A frequent finding was the persistence of mild hyperthy-rotropinemia. The evolution of CH remains difficult to predict, although different clinical features might suggest different outcomes. Mutations in the genes commonly linked to mild forms of CH were documented in a minority of cases.

Consumptive hypothyroidism is a rare condition related to massive infantile hemangiomas producing an excess of the thyroid-hormone-inactivating enzyme type 3 iodothyronine deiodinase. We report the first case of consumptive hypothyroidism secondary to a large parotid hemangioma, highlighting the difficulties in selecting an adequate therapeutic strategy. The affected child was initially referred to our center for congenital hypothyroidism with a hypoplastic thyroid gland. L-Thyroxine (L-T4) replacement therapy was started at seven days of life. In the following weeks, the hemangioma rapidly increased in volume and the child developed severe hypothyroidism refractory to high doses of L-T4 therapy. The concentration of reverse triiodothyronine was elevated, suggesting that the underlying cause was an excessive conversion of thyroid hormones by high type 3 iodothyronine deiodinase levels in the tumor. Corticosteroid treatment showed only partial benefit. Introduction of propranolol instead led to normalization of thyroid hormones along with a dramatic involution of the hemangioma.