A single copy of the recently identified dual oxidase maturation factor (DUOXA) 1 gene produces only mild transient hypothyroidism in a patient with a novel biallelic DUOXA2 mutation and monoallelic DUOXA1 deletion.

CONTEXT: Dual oxidases (DUOX1 and DUOX2) play a crucial role in the generation of hydrogen peroxide required in the oxidation of iodide and the synthesis of thyroid hormone. Heterodimerization with specific maturation factors (DUOXA1 and DUOXA2) is essential for the maturation and function of the DUOX enzyme complexes. Biallelic loss-of-function mutations of DUOX2 result in congenital hypothyroidism (CH), whereas a single reported case of homozygous DUOXA2 mutation (Y246X) has been associated with mild CH. OBJECTIVE: We now report an infant with transient CH due to a complex genetic alteration of the DUOX/DUOXA system. RESULTS: Our patient was born to euthyroid nonconsanguineous parents and presented with an elevated TSH and enlarged thyroid gland at neonatal screening. Genetic analysis revealed a missense mutation (C189R) on the maternal DUOXA2 allele. The mutant DUOXA2 protein showed complete loss-of-function in reconstituting DUOX2 in vitro. The apparent C189R homozygosity of the proband in the absence of the same mutation in the father led to detailed gene mapping, revealing an approximately 43-kb pair deletion encompassing DUOX2, DUOXA1, and DUOXA2. Thus, in addition to being deficient in DUOXA2, the proband lacks one allele of DUOX2 and DUOXA1 but has two functioning DUOX1 alleles. CONCLUSION: The transient CH in the presence of only one functional maturation factor allele indicates a high level of functional redundancy in the DUOX/DUOXA system.

Insulin detemir is characterized by a more reproducible pharmacokinetic profile than insulin glargine in children and adolescents with type 1 diabetes: results from a randomized, double-blind, controlled trial.

Insulin detemir (detemir) has previously been shown to be associated with lower within-subject variability compared with other basal insulin preparations in adults with type 1 diabetes mellitus (T1DM). This randomized, double-blind, crossover trial compared the within-subject variability of detemir and insulin glargine (glargine) in pharmacokinetic properties in children and adolescents with T1DM. The trial enrolled 32 children and adolescents (19 girls and 13 boys; mean +/- SD: age 13 +/- 2.5 yr and T1DM duration 6.3 +/- 3.0 yr) with a hemoglobin A1c (HbA1c) of 7.9 +/- 1.0%. Participants were randomized to a specific treatment sequence in which a dose of 0.4 U/kg of detemir and glargine was injected subcutaneously 24 h apart at each of two dosing visits. Insulin concentrations were measured at frequent intervals for a period of 16-h post-dosing. Detemir showed statistically significantly less within-subject variability compared with glargine with a 3.1-fold and 2.9-fold lower coefficient of variation (CV, %) for the area under the concentration-time curve [AUC((0-16) (h))] and the maximum concentration (C(max)), respectively. Separate analyses demonstrated a 2.5-fold and 2.9-fold lower CV (%) with detemir in children (8-12 yr) and a 4-fold and 3.8-fold lower CV (%) with detemir in adolescents (13-17 yr). No safety concerns were raised during the trial. In conclusion, within-subject variability in pharmacokinetic properties was significantly lower for detemir than for glargine in children and adolescents with T1DM. This indicates a less variable absorption with detemir, which is expected to be associated with a more predictable therapeutic effect also in this population.

Current practice of insulin pump therapy in children and adolescents - the Hannover recipe.

Increasing evidence points to the importance of achieving low blood glucose variability and also a low hemoglobin A1c (HbA1c) to prevent diabetic late complications. Continuous subcutaneous insulin infusion (CSII) is associated with lower blood glucose variability in children. Frequent indications for starting CSII in youth are recurrent hypoglycemia, need for increased flexibility, poor glycemic control, dawn phenomenon, or needle phobia. At our center, about one-third of all patients across all age groups are currently on CSII. Although the average glycemic control is not very different from those on multiple daily injections, fewer patients are seen in the segment of very high and very low HbA1c with CSII. Across centers, the 'recipes' tailoring CSII treatment to individual patients and cultures are based more on experience than on evidence. However, several typical pediatric features have been identified. Patterns of the hourly basal rate and prandial insulin requirements vary with age. While many adolescents have increased requirements at dawn and dusk, young children show increasing needs in the second half of the day. Low insulin requirements, particularly in neonates, may need insulin dilution. The selection of catheters and needles has to be appropriate for the age. The opportunity to have an electronic memory read-out of all entries and alarms offers new possibilities of therapeutic monitoring, particularly in those youth not keeping good logbooks. This feature can be helpful, if a trustful relationship between the diabetes team and the family is established.