Dual oxidases (DUOX1 and DUOX2) are evolutionary conserved reduced nicotinamide adenine dinucleotide phosphate oxidases responsible for regulated hydrogen peroxide (H(2)O(2)) release of epithelial cells. Specific maturation factors (DUOXA1 and DUOXA2) are required for targeting of functional DUOX enzymes to the cell surface. Mutations in the single-copy Duox and Duoxa genes of invertebrates cause developmental defects with reduced survival, whereas knockdown in later life impairs intestinal epithelial immune homeostasis. In humans, mutations in both DUOX2 and DUOXA2 can cause congenital hypothyroidism with partial iodide organification defects compatible with a role of DUOX2-generated H(2)O(2) in driving thyroid peroxidase activity. The DUOX1/DUOXA1 system may account for residual iodide organification in patients with loss of DUOX2, but its physiological function is less clear. To provide a murine model recapitulating complete DUOX deficiency, we simultaneously targeted both Duoxa genes by homologous recombination. Knockout of Duoxa genes (Duoxa(-/-) mice) led to a maturation defect of DUOX proteins lacking Golgi processing of N-glycans and to loss of H(2)O(2) release from thyroid tissue. Postnatally, Duoxa(-/-) mice developed severe goitreous congenital hypothyroidism with undetectable serum T4 and maximally disinhibited TSH levels. Heterozygous mice had normal thyroid function parameters. (125)I uptake and discharge studies and probing of iodinated TG epitopes corroborated the iodide organification defect in Duoxa(-/-) mice. Duoxa(-/-) mice on continuous T4 replacement from P6 showed normal growth without an overt phenotype. Our results confirm in vivo the requirement of DUOXA for functional expression of DUOX-based reduced nicotinamide adenine dinucleotide phosphate oxidases and the role of DUOX isoenzymes as sole source of hormonogenic H(2)O(2).

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SummaryThree-drug induction regimens have become the standard of care in newly diagnosed transplant-eligible multiple myeloma patients. Two frequently used protocols are bortezomib, cyclophosphamide and dexamethasone (VCD) and bortezomib, thalidomide and dexamethasone (VTD). Comparisons between the two are lacking. The present study aimed to identify the differences in response rate and toxicity between the two regimens. Databases were searched using the terms 'VTD' or 'VCD' and 'induction regimens for newly diagnosed multiple myeloma'. Prospective trials evaluating initial response in transplant eligible patients were included. The main outcome measures were response rates and adverse events. Eight clinical trials were eligible for analysis. Overall 672 patients were treated with either VCD (n = 157) or VTD (n = 515) as induction therapy. Patients treated with VTD presented with a significantly higher complete/near complete response (34% vs. 6%, P = 0Á002) as well as a higher very good partial response rate or better, following induction therapy (62% vs. 27%, P < 0Á0001). Although grade 3-4 neurotoxicity was more frequent during VTD therapy (11% vs. 6%, P = 0Á057), a higher incidence of overall grade 3-4 adverse events was found in the VCD-treated patients (74% vs. 51%, P < 0Á001). VTD induction therapy may be superior in achieving deeper response rate following induction therapy, and is better tolerated.

TSHR and TPO gene mutations were identified alone and together in individuals of a consanguineous kindred. Homozygotes for the TSHR and a compound heterozygote for the TPO mutations were hypothyroid. The mild hyperthyrotropinemia of heterozygotes for the mutant TSHR allele was not aggravated by the coexistence of a TPO defect in one allele.