DCC/NTN1 complex mutations in patients with congenital hypogonadotropic hypogonadism impair GnRH neuron development.

Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disease characterized by absent puberty and infertility due to GnRH deficiency, and is often associated with anosmia [Kallmann syndrome (KS)]. The genetic etiology of CHH is heterogeneous, and more than 30 genes have been implicated in approximately 50% of patients with CHH. We hypothesized that genes encoding axon-guidance proteins containing fibronectin type-III (FN3) domains (similar to ANOS1, the first gene associated with KS), are mutated in CHH. We performed whole-exome sequencing in a cohort of 133 CHH probands to test this hypothesis, and identified rare sequence variants (RSVs) in genes encoding for the FN3-domain encoding protein deleted in colorectal cancer (DCC) and its ligand Netrin-1 (NTN1). In vitro studies of these RSVs revealed altered intracellular signaling associated with defects in cell morphology, and confirmed five heterozygous DCC mutations in 6 probands-5 of which presented as KS. Two KS probands carry heterozygous mutations in both DCC and NTN1 consistent with oligogenic inheritance. Further, we show that Netrin-1 promotes migration in immortalized GnRH neurons (GN11 cells). This study implicates DCC and NTN1 mutations in the pathophysiology of CHH consistent with the role of these two genes in the ontogeny of GnRH neurons in mice.

[Polycystic ovary syndrome in obese or type 1 diabetic (T1D) adolescent girls]. / Syndrome des ovaires polykystiques chez l'adolescente diabétique ou obèse.

Polycystic ovary syndrome (PCOS) is frequent during adolescence (prevalence ≈ 6 %), and the prevalence increases in obese or type 1 diabetic (T1D) adolescent girls. During puberty, PCOS diagnosis is difficult because of the overlap with some pubertal physiologic signs. The 2017 international consortium suggests two required diagnostic criteria: persistent menstrual disturbances and hyperandrogenism. PCOS physiopathology is complex, including interactions between genetic, epigenetic factors, primary ovarian abnormalities, neuroendocrine alterations, hormonal and metabolic factors. Insulin seems to have a central place in obese or T1D adolescent girls. The treatment is still debated and should be monitored according to the main symptoms.

Le syndrome des ovaires polykystiques (SOPK) est fréquent à l'adolescence (prévalence ≈ 6 %), et la prévalence augmente en cas d'obésité ou de diabète de type 1 (DT1). À l'adolescence, le diagnostic du SOPK est difficile en raison de signes communs avec la puberté physiologique. Le consortium international de 2017 propose deux critères diagnostiques indispensables : les troubles du cycle menstruel et l'hyperandrogénie. La physiopathologie du SOPK, partiellement élucidée, est complexe, impliquant l'interaction entre des facteurs génétiques et épigénétiques, des anomalies ovariennes, des altérations neuroendocrines, des facteurs hormonaux et métaboliques. L'insuline semble avoir un rôle central chez l'adolescente obèse ou avec DT1. Le traitement fait encore l'objet de discussion et doit être adapté selon les signes prédominants.

Accuracy, satisfaction and usability of a flash glucose monitoring system among children and adolescents with type 1 diabetes attending a summer camp.

BACKGROUND: The study aimed to assess accuracy, satisfaction and usability of a flash glucose monitoring system (FGM) in children and adolescents with type 1 diabetes mellitus (T1DM) attending a diabetes summer camp. METHODS: Sixty-six children and adolescents with T1DM aged 6 to 17 years participating in a 7-day medically supervised summer camp were enrolled. Capillary blood glucose (BG) and flash glucose (FG) values were measured simultaneously at breakfast, lunch, and dinner and for any given FG value <72 mg/dL (<4.0 mmol/L) during daytime, <108 mg/dL (<6.0 mmol/L) at nighttime, >270 mg/dL (>15.0 mmol/L) or when patient symptoms were discordant with sensor readings. Sensor-related issues were documented and patients' and healthcare professionals' (HCPs) satisfaction was evaluated. RESULTS: FGM demonstrated satisfactory clinical accuracy compared to reference capillary BG values with 98.8% of values falling within the clinically acceptable zones (A and B) of the consensus error grid. Overall mean absolute relative difference (MARD) was 16.7% ± 16.1%. Specific calculations of mean absolute difference (MAD), mean relative difference (MRD), and mean difference (MD) demonstrated that FGM overestimated BG values across all glycemic ranges. Overall satisfaction with the FGM was high in 91.7% participants and 95.0% HCPs, although confidence in the system was low in 18.0% participants and 40.0% HCPs. CONCLUSIONS: The FGM exhibited satisfactory clinical accuracy. However, based on the present data, we conclude that no decision should be taken on the basis of a single, non-verified, FGM value alone. Our study highlights the need for revised therapeutic education for patients/families and further investigation on the integration of sensor readings in clinical decision-making.

A novel CHD7 mutation in an adolescent presenting with growth and pubertal delay.

Mutations in the CHD7 gene, encoding for the chromodomain helicase DNA-binding protein 7, are found in approximately 60% of individuals with CHARGE syndrome (coloboma, heart defects, choanal atresia, retarded growth and development, genital hypoplasia, ear abnormalities and/or hearing loss). Herein, we present a clinical case of a 14-year-old male presenting for evaluation of poor growth and pubertal delay highlighting the diagnostic challenges of CHARGE syndrome. The patient was born full term and underwent surgery at 5 days of life for bilateral choanal atresia. Developmental milestones were normally achieved. At age 14 his height and weight were -2.04 and -1.74 standard deviation score respectively. He had anosmia as well as prepubertal testes and micropenis (4 cm×1 cm). The biological profile showed low basal serum testosterone and gonadotropins (testosterone, 0.2 nmol/L; luteinizing hormone, 0.5 U/L; follicle-stimulating hormone, 1.3 U/L), and otherwise normal pituitary function and normal imaging of the hypothalamic-pituitary area. The constellation of choanal atresia, anosmia, mild dysmorphic features, micropenis and delayed puberty were suggestive of CHARGE syndrome. Targeted genetic testing of CHD7 was performed revealing a de novo heterozygous CHD7 mutation (c.4234T>G [p.Tyr1412Asp]). Further paraclinical investigations confirmed CHARGE syndrome. Despite the presence of suggestive features, CHARGE syndrome remained undiagnosed in this patient until adolescence. Genetic testing helps clarify the phenotypic and genotypic spectrum to facilitate diagnosis, thus promoting optimal follow-up, treatment, and appropriate genetic counselling.

TRANSITION IN ENDOCRINOLOGY: Hypogonadism in adolescence.

Puberty is a remarkable developmental process with the activation of the hypothalamic-pituitary-gonadal axis culminating in reproductive capacity. It is accompanied by cognitive, psychological, emotional, and sociocultural changes. There is wide variation in the timing of pubertal onset, and this process is affected by genetic and environmental influences. Disrupted puberty (delayed or absent) leading to hypogonadism may be caused by congenital or acquired etiologies and can have significant impact on both physical and psychosocial well-being. While adolescence is a time of growing autonomy and independence, it is also a time of vulnerability and thus, the impact of hypogonadism can have lasting effects. This review highlights the various forms of hypogonadism in adolescence and the clinical challenges in differentiating normal variants of puberty from pathological states. In addition, hormonal treatment, concerns regarding fertility, emotional support, and effective transition to adult care are discussed.

Natural history of growth hormone deficiency in a pediatric cohort.

BACKGROUND/AIMS: Controversies still exist regarding the evaluation of growth hormone deficiency (GHD) in childhood at the end of growth. The aim of this study was to describe the natural history of GHD in a pediatric cohort. METHODS: This is a retrospective study of a cohort of pediatric patients with GHD. Cases of acquired GHD were excluded. Univariate logistic regression was used to identify predictors of GHD persisting into adulthood. RESULTS: Among 63 identified patients, 47 (75%) had partial GHD at diagnosis, while 16 (25%) had complete GHD, including 5 with multiple pituitary hormone deficiencies. At final height, 50 patients underwent repeat stimulation testing; 28 (56%) recovered and 22 (44%) remained growth hormone (GH) deficient. Predictors of persisting GHD were: complete GHD at diagnosis (OR 10.1, 95% CI 2.4-42.1), pituitary stalk defect or ectopic pituitary gland on magnetic resonance imaging (OR 6.5, 95% CI 1.1-37.1), greater height gain during GH treatment (OR 1.8, 95% CI 1.0-3.3), and IGF-1 level <-2 standard deviation scores (SDS) following treatment cessation (OR 19.3, 95% CI 3.6-103.1). In the multivariate analysis, only IGF-1 level <-2 SDS (OR 13.3, 95% CI 2.3-77.3) and complete GHD (OR 6.3, 95% CI 1.2-32.8) were associated with the outcome. CONCLUSION: At final height, 56% of adolescents with GHD had recovered. Complete GHD at diagnosis, low IGF-1 levels following retesting, and pituitary malformation were strong predictors of persistence of GHD.