Search Results

Background

Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes and usually presents in the first 6 months of life. We aimed to describe the clinical characteristics and molecular genetics of a large Turkish cohort of NDM patients from a single centre and estimate an annual incidence rate of NDM in South-Eastern Anatolian region of Turkey.

Design and methods

NDM patients presenting to Diyarbakir Children State Hospital between 2010 and 2013, and patients under follow-up with presumed type 1 diabetes mellitus, with onset before 6 months of age were recruited. Molecular genetic analysis was performed.

Results

Twenty-two patients (59% males) were diagnosed with NDM (TNDM-5; PNDM-17). Molecular genetic analysis identified a mutation in 20 (95%) patients who had undergone a mutation analysis. In transient neonatal diabetes (TNDM) patients, the genetic cause included chromosome 6q24 abnormalities (n=3), ABCC8 (n=1) and homozygous INS (n=1). In permanent neonatal diabetes (PNDM) patients, homozygous GCK (n=6), EIF2AK3 (n=3), PTF1A (n=3), and INS (n=1) and heterozygous KCNJ11 (n=2) mutations were identified. Pancreatic exocrine dysfunction was observed in patients with mutations in the distal PTF1A enhancer. Both patients with a KCNJ11 mutation responded to oral sulphonylurea. A variable phenotype was associated with the homozygous c.-331C>A INS mutation, which was identified in both a PNDM and TNDM patient. The annual incidence of PNDM in South-East Anatolian region of Turkey was one in 48 000 live births.

Conclusions

Homozygous mutations in GCK, EIF2AK3 and the distal enhancer region of PTF1A were the commonest causes of NDM in our cohort. The high rate of detection of a mutation likely reflects the contribution of new genetic techniques (targeted next-generation sequencing) and increased consanguinity within our cohort.

Objective

Transient neonatal hyperthyrotropinemia (TNH) is defined as a neonatal abnormality of thyroid function, which reverts to normal at re-examination after 2 weeks of life. The thyroid function of these infants has not been sufficiently studied in terms of the risk of developing persistent hyperthyrotropinemia (PH) in later childhood and its impact on growth and development.

Design

A prospective cohort study included all babies born in our hospital between 2001 and 2006 and screened for hypothyroidism, whose thyroid function was re-examined 6 years later. Exclusion criteria included the following conditions: preterm birth, birth weight <2500 g, Down's syndrome, descendants of mothers with immune thyroid disease, congenital malformations, cardiac, renal, hepatic, and metabolic diseases, and steroid or dopamine medication. The variables included are TSH and thyroxine at neonatal screening and 6 years later. Main outcomes are the risk of developing PH in childhood, linear growth, and development using Parents' Evaluation of Developmental Status (PEDS).

Results

Out of 5040 normal-term newborns, 301 (6.0%, 95% CI 5.3–6.6%) have TSH ≥10 mU/l (TNH). Six years later, we re-examined 65 randomly selected children with TNH and 185 controls. In the TNH cohort, we found six out of 65 children (9.2%, 95% CI 1.4–17.0%) with PH (TSH ≥6.4 mU/l), and three out of 185 (1.6%, 95% CI 0.3–4.7%) among controls, relative risk 5.7 (95% CI 1.5–22.1), P=0.0114. TSH and developmental delay were found to be significantly higher in the TNH cohort (4.7±1.3 mU/l vs 2.1±0.5 mU/l, P<0.0001 and 15/65 (23%, 95% CI 12–34.1) vs 21/185 (11.3%, 95% CI 6.5–16.2) P=0.0348).

Conclusions

Newborns with TNH have a higher risk of developing PH in childhood, with repercussion on developmental status.

Objective

We assessed the characteristics of children initially diagnosed with idiopathic isolated GH deficiency (IGHD) who later developed additional (multiple) pituitary hormone deficiencies (MPHD).

Design

Data were analyzed for 5805 pediatric patients with idiopathic IGHD, who were GH-naïve at baseline and GH-treated in the multinational, observational Genetics and Neuroendocrinology of Short Stature International Study.

Methods

Development of MPHD was assessed from investigator diagnoses, adverse events, and concomitant medications. Analyses were performed for all patients and for those who developed MPHD within 4.5 years or had ≥3.5 years, follow-up and continued to have IGHD (4-year cohort).

Results

MPHD developed in 118/5805 (2.0%) children overall, and in 96/1757 (5.5%) in the 4-year cohort. Patients who developed MPHD had more profound GHD, with decreased height SDS, IGF1 SDS and peak stimulated GH, and greater height decrement vs target, compared with children who continued to have IGHD (P<0.001 for each variable). Delivery complications, congenital anomalies, and perinatal/neonatal adverse events occurred more frequently in patients who developed MPHD. The most frequent additional deficiency was TSH (82 patients overall); four patients developed two pituitary hormone deficiencies and one developed three deficiencies. Multivariable logistic regression indicated that years of follow-up (odds ratio 1.55), baseline age (1.17), baseline height SDS (0.69), and peak stimulated GH (0.64) were associated with the development of MPHD.

Conclusions

MPHD is more likely to develop in patients with more severe idiopathic IGHD. Older baseline age, lower baseline height SDS, and longer follow-up duration are associated with increased risk of development of MPHD.

Objective

Congenital hyperinsulinism (CHI) is the commonest cause of hyperinsulinaemic hypoglycaemia in the neonatal, infancy and childhood periods. Its clinical presentation, histology and underlying molecular biology are extremely heterogeneous. The aim of this study was to describe the clinical characteristics, analyse the genotype–phenotype correlations and describe the treatment outcome of Turkish CHI patients.

Design and methods

A total of 35 patients with CHI were retrospectively recruited from four large paediatric endocrine centres in Turkey. Detailed clinical, biochemical and genotype information was collected.

Results

Diazoxide unresponsiveness was observed in nearly half of the patients (n=17; 48.5%). Among diazoxide-unresponsive patients, mutations in ABCC8/KCNJ11 were identified in 16 (94%) patients. Among diazoxide-responsive patients (n=18), mutations were identified in two patients (11%). Genotype–phenotype correlation revealed that mutations in ABCC8/KCNJ11 were associated with an increased birth weight and early age of presentation. Five patients had p.L1171fs (c.3512del) ABCC8 mutations, suggestive of a founder effect. The rate of detection of a pathogenic mutation was higher in consanguineous families compared with non-consanguineous families (87.5 vs 21%; P<0.0001).

Among the diazoxide-unresponsive group, ten patients were medically managed with octreotide therapy and carbohydrate-rich feeds and six patients underwent subtotal pancreatectomy. There was a high incidence of developmental delay and cerebral palsy among diazoxide-unresponsive patients.

Conclusions

This is the largest study to report genotype–phenotype correlations among Turkish patients with CHI. Mutations in ABCC8 and KCNJ11 are the commonest causes of CHI in Turkish patients (48.6%). There is a higher likelihood of genetic diagnosis in patients with early age of presentation, higher birth weight and from consanguineous pedigrees.

Objective

To evaluate adrenal crises after the start of treatment up to the age of 6 years in children with classic congenital adrenal hyperplasia (CAH).

Design

Analysis of data extracted from a population-based prospective long-term follow-up study of children detected in neonatal screening.

Methods

Data of 102 Bavarian children with classic CAH due to 21-hydroxylase deficiency were analyzed, using parental questionnaires and medical reports. Parent-reported hospital admissions of children diagnosed with acute health impairment were included in the analysis if salt loss (hyponatremia) or hypoglycemia was documented in the discharge summary.

Results

A total of 74 children (72.5%) had no report of hospital admissions with salt loss or hypoglycemia during the observational period. However, in 27.5% of the children, 22 salt-wasting crises (seven of these also with low blood glucose) and 16 hypoglycemic episodes without salt loss were reported. Furthermore, the cumulative incidence for seizures was elevated; 13 children experienced seizures during hyponatremia or hypoglycemia. Most adrenal crises were triggered by infections, often with inappropriate emergency management, but in 11 cases hypoglycemia occurred unexpectedly, without evidence of severe illness and without any management errors. Frequency of adrenal crises was 6.5 per 100 patient years (95% CI: 4.6–8.8).

Conclusions

Crisis prevention remains a permanent challenge for families and physicians caring for children with classic CAH. Expert care and compliance with emergency recommendations are crucial. Further research on the interactions among glucocorticoid deficiency, adrenomedullary dysfunction, and glucose metabolism is necessary for the prevention of hypoglycemia, especially in young CAH patients.

Context:

Accurate hydrocortisone dosing in children with adrenal insufficiency is important to avoid the risks of over and under treatment including iatrogenic Cushing’s syndrome and adrenal crisis.

Objective:

To establish a population pharmacokinetic model of hydrocortisone in children and use this to refine hydrocortisone replacement regimens.

Design and methods:

Pharmacokinetic study of hydrocortisone granules, available in 0.5, 1, 2 and 5 mg dose strengths, in 24 children with adrenal insufficiency aged 2 weeks to 6 years. Cortisol concentrations quantified by LC-MS/MS were used to refine an adult pharmacokinetic model to a paediatric population model which was then used to simulate seven different hydrocortisone treatment regimens.

Results:

Pre-dose cortisol levels were undetectable in 54% of the 24 children. The developed pharmacokinetic model had good predictive performance. Simulations for the seven treatment regimens using either three- or four-times daily dosing showed treatment regimens delivered an AUC_{0- 24h} within the 90% reference range for healthy children except in neonates where two regimens had an AUC below the 5th percentile. Cortisol concentrations at individual time points in the 24 h were outside the 90% reference range for healthy individuals in 50%, 55–65% and 70–75% for children, infants and neonates, respectively, with low cortisol levels being most prevalent.

Conclusions:

Current paediatric hydrocortisone treatment regimens based on either three- or four-times daily administration replicate cortisol exposure based on AUC_{0- 24h}, but the majority of cortisol levels are above or below physiological cortisol levels with low levels very common before the next dose.