Copeptin improves prediction of treatment response in children with monosymptomatic nocturnal enuresis

OBJECTIVE

One of the main medical treatment options for monosymptomatic nocturnal enuresis (MNE) is the vasopressin analog desmopressin. But not all children respond to desmopressin treatment, and no reliable treatment predictor has yet been established. We hypothesize that plasma copeptin, a surrogate marker for vasopressin, can be used to predict treatment response to desmopressin in children with MNE.

DESIGN/METHODS

In this prospective observational study, we included 28 children with MNE. At baseline, we assessed the number of wet nights, morning, and evening plasma copeptin, and plasma sodium and started treatment with desmopressin (120 µg daily). Desmopressin was increased to 240 µg daily if clinically necessary. The primary endpoint was reduction in the number of wet nights following 12 weeks of treatment with desmopressin using plasma copeptin ratio (evening/morning copeptin) at baseline.

RESULTS

Eighteen children responded to desmopressin treatment at 12 weeks, while 9 did not. A copeptin ratio cutoff of 1.34 (sensitivity 55.56%, specificity 94.12%, area under the curve 70.6%, P = .07) was best at predicting treatment response, with a lower ratio indicating a better treatment response. In contrast, neither the number of wet nights at baseline (P = .15) nor serum sodium (P = .11) alone or in combination with plasma copeptin improved outcome prediction.

CONCLUSIONS

Our results indicate that, of our investigated parameters, plasma copeptin ratio is the best predictor for treatment response in children with MNE. Plasma copeptin ratio could thus be useful to identify children with the highest benefit of desmopressin treatment and improve individualized treatment of MNE.

Glucagon-stimulated copeptin measurements in the differential diagnosis of diabetes insipidus: a double-blind, randomized, placebo-controlled study

BACKGROUND

The differential diagnosis of diabetes insipidus is challenging. The most reliable approaches are copeptin measurements after hypertonic saline infusion or arginine, which is a known growth hormone secretagogue but has recently also been shown to stimulate the neurohypophysis. Similar to arginine, glucagon stimulates growth hormone release, but its effect on the neurohypophysis is poorly studied.

DESIGN

Double-blind, randomized, placebo-controlled trial including 22 healthy participants, 10 patients with central diabetes insipidus, and 10 patients with primary polydipsia at the University Hospital Basel, Switzerland.

METHODS

Each participant underwent the glucagon test (s.c. injection of 1 mg glucagon) and placebo test. The primary objective was to determine whether glucagon stimulates copeptin and to explore whether the copeptin response differentiates between diabetes insipidus and primary polydipsia. Copeptin levels were measured at baseline, 30, 60, 90, 120, 150, and 180 min after injection.

RESULTS

In healthy participants, glucagon stimulated copeptin with a median increase of 7.56 (2.38; 28.03) pmol/L, while placebo had no effect (0.10 pmol/L (-0.70; 0.68); P < 0.001). In patients with diabetes insipidus, copeptin showed no relevant increase upon glucagon, with an increase of 0.55 (0.21; 1.65) pmol/L, whereas copeptin was stimulated in patients with primary polydipsia with an increase of 15.70 (5.99; 24.39) pmol/L. Using a copeptin cut-off level of 4.6pmol/L had a sensitivity of 100% (95% CI: 100-100) and a specificity of 90% (95% CI: 70-100) to discriminate between diabetes insipidus and primary polydipsia.

CONCLUSION

Glucagon stimulates the neurohypophysis, and glucagon-stimulated copeptin has the potential for a safe, novel, and precise test in the differential diagnosis of diabetes insipidus.

Gonadectomy in conditions affecting sex development: a registry-based cohort study

OBJECTIVES

To determine trends in clinical practice for individuals with DSD requiring gonadectomy.

DESIGN

Retrospective cohort study.

METHODS

Information regarding age at gonadectomy according to diagnosis; reported sex; time of presentation to specialist centre; and location of centre from cases reported to the International DSD Registry and who were over 16 years old in January 2019.

RESULTS

Data regarding gonadectomy were available in 668 (88%) individuals from 44 centres. Of these, 248 (37%) (median age (range) 24 (17, 75) years) were male and 420 (63%) (median age (range) 26 (16, 86) years) were female. Gonadectomy was reported from 36 centres in 351/668 cases (53%). Females were more likely to undergo gonadectomy (n = 311, P < 0.0001). The indication for gonadectomy was reported in 268 (76%). The most common indication was mitigation of tumour risk in 172 (64%). Variations in the practice of gonadectomy were observed; of the 351 cases from 36 centres, 17 (5%) at 9 centres had undergone gonadectomy before their first presentation to the specialist centre. Median age at gonadectomy of cases from high-income countries and low-/middle-income countries (LMIC) was 13.0 years (0.1, 68) years and 16.5 years (1, 28), respectively (P < 0.0001) with the likelihood of long-term retention of gonads being higher in LMIC countries.

CONCLUSIONS

The likelihood of gonadectomy depends on the underlying diagnosis, sex of rearing and the geographical setting. Clinical benchmarks, which can be studied across all forms of DSD will allow a better understanding of the variation in the practice of gonadectomy.

A novel GATA6 variant in a boy with neonatal diabetes and diaphragmatic hernia: a familial case with a review of the literature

GATA6 gene variants come along with possible features such as pancreas agenesis/hypoplasia, neonatal diabetes and congenital heart defect. Congenital hypothyroidism, and hepatobiliary and gut abnormalities are also detectable. Children with congenital heart defects and neonatal diabetes were already described in 1970. GATA6 variants can be due to de novo variants or due to inherited variants. To date, 11 cases due to an inherited variant have been described. Herein we present a novel heterozygous GATA6 variant (c.1291C > T p.[Gln431*]) in a boy with transient neonatal diabetes, diaphragmatic hernia, congenital heart defect and early-onset scoliosis. The same variant was also present in the mother. At the age of 3 years, a random evaluation revealed a hemoglobin A1c (HbA1c) level of 7.8% (62 mmol/mol) without any diabetes-related symptoms. He was started on insulin therapy and HbA1c normalized. A short review of the literature of hereditary cases of the GATA6 variant revealed the variable phenotypic spectrum and showed that patients with a mild phenotype are likely to have children with a more severe phenotype.