Congenital hyperinsulinism. / Medfødt hyperinsulinisme.

This clinical review will give doctors who work with children and neonates an introduction to the diagnosis and treatment of congenital hyperinsulinism, the most common cause of persistent neonatal hypoglycaemia. The condition is a rare monogenic disorder characterised by elevated insulin secretion and is a result of mutations in genes that regulate insulin secretion from pancreatic beta cells. The anabolic effect of insulin induces systemic glucose uptake and inhibits gluconeogenesis, glycogenolysis, ketogenesis and lipolysis. Low levels of glucose and ketone bodies in the blood are harmful to the central nervous system and can lead to brain damage or death. Early diagnosis and treatment of congenital hyperinsulinism are therefore crucial for a good prognosis.

Janus-faced EPHB4-associated disorders: novel pathogenic variants and unreported intrafamilial overlapping phenotypes.

PURPOSE: Several clinical phenotypes including fetal hydrops, central conducting lymphatic anomaly or capillary malformations with arteriovenous malformations 2 (CM-AVM2) have been associated with EPHB4 (Ephrin type B receptor 4) variants, demanding new approaches for deciphering pathogenesis of novel variants of uncertain significance (VUS) identified in EPHB4, and for the identification of differentiated disease mechanisms at the molecular level. METHODS: Ten index cases with various phenotypes, either fetal hydrops, CM-AVM2, or peripheral lower limb lymphedema, whose distinct clinical phenotypes are described in detail in this study, presented with a variant in EPHB4. In vitro functional studies were performed to confirm pathogenicity. RESULTS: Pathogenicity was demonstrated for six of the seven novel EPHB4 VUS investigated. A heterogeneity of molecular disease mechanisms was identified, from loss of protein production or aberrant subcellular localization to total reduction of the phosphorylation capability of the receptor. There was some phenotype-genotype correlation; however, previously unreported intrafamilial overlapping phenotypes such as lymphatic-related fetal hydrops (LRFH) and CM-AVM2 in the same family were observed. CONCLUSION: This study highlights the usefulness of protein expression and subcellular localization studies to predict EPHB4 variant pathogenesis. Our accurate clinical phenotyping expands our interpretation of the Janus-faced spectrum of EPHB4-related disorders, introducing the discovery of cases with overlapping phenotypes.

Insight Into the Ontogeny of GnRH Neurons From Patients Born Without a Nose.

CONTEXT: The reproductive axis is controlled by a network of gonadotropin-releasing hormone (GnRH) neurons born in the primitive nose that migrate to the hypothalamus alongside axons of the olfactory system. The observation that congenital anosmia (inability to smell) is often associated with GnRH deficiency in humans led to the prevailing view that GnRH neurons depend on olfactory structures to reach the brain, but this hypothesis has not been confirmed. OBJECTIVE: The objective of this work is to determine the potential for normal reproductive function in the setting of completely absent internal and external olfactory structures. METHODS: We conducted comprehensive phenotyping studies in 11 patients with congenital arhinia. These studies were augmented by review of medical records and study questionnaires in another 40 international patients. RESULTS: All male patients demonstrated clinical and/or biochemical signs of GnRH deficiency, and the 5 men studied in person had no luteinizing hormone (LH) pulses, suggesting absent GnRH activity. The 6 women studied in person also had apulsatile LH profiles, yet 3 had spontaneous breast development and 2 women (studied from afar) had normal breast development and menstrual cycles, suggesting a fully intact reproductive axis. Administration of pulsatile GnRH to 2 GnRH-deficient patients revealed normal pituitary responsiveness but gonadal failure in the male patient. CONCLUSIONS: Patients with arhinia teach us that the GnRH neuron, a key gatekeeper of the reproductive axis, is associated with but may not depend on olfactory structures for normal migration and function, and more broadly, illustrate the power of extreme human phenotypes in answering fundamental questions about human embryology.

Selective ultrasound screening for developmental hip dysplasia: effect on management and late detected cases. A prospective survey during 1991-2006.

BACKGROUND: Early treatment is considered essential for developmental dysplasia of the hip (DDH), but the choice of screening strategy is debated. OBJECTIVE: We evaluated the effect of a selective ultrasound (US) screening programme. MATERIALS AND METHODS: All infants born in a defined region during 1991-2006 with increased risk of developmental dysplasia of the hip, i.e. clinical hip instability, breech presentation, congenital foot deformities or a family history of DDH, underwent US screening at age 1-3 days. Severe sonographic dysplasia and dislocatable/dislocated hips were treated with abduction splints. Mild dysplasia and pathological instability, i.e. not dislocatable/dislocated hips were followed clinically and sonographically until spontaneous resolution, or until treatment became necessary. The minimum observation period was 5.5 years. RESULTS: Of 81,564 newborns, 11,539 (14.1%) were identified as at-risk, of whom 11,190 (58% girls) were included for further analyses. Of the 81,564 infants, 2,433 (3.0%) received early treatment; 1,882 (2.3%) from birth and 551 (0.7%) after 6 weeks or more of clinical and sonographic surveillance. An additional 2,700 (3.3%) normalised spontaneously after watchful waiting from birth. Twenty-six infants (0.32 per 1,000, 92% girls, two from the risk group) presented with late subluxated/dislocated hips (after 1 month of age). An additional 126 (1.5 per 1,000, 83% girls, one from the risk group) were treated after isolated late residual dysplasia. Thirty-one children (0.38 per 1,000) had surgical treatment before age 5 years. Avascular necrosis was diagnosed in seven of all children treated (0.27%), four after early and three after late treatment. CONCLUSION: The first 16 years of a standardised selective US screening programme for developmental dysplasia of the hip resulted in acceptable rates of early treatment and US follow-ups and low rates of late subluxated/dislocated hips compared to similar studies.

Immediate treatment versus sonographic surveillance for mild hip dysplasia in newborns.

OBJECTIVE: We conducted a blinded, randomized, controlled trial to examine whether mildly dysplastic but stable or instable hips would benefit from early treatment, as compared with watchful waiting. PATIENTS AND METHODS: A total of 128 newborns with mild hip dysplasia (sonographic inclination angle [alpha angle] of 43 degrees -49 degrees ) and stable or instable but not dislocatable hips were randomly assigned to receive either 6 weeks of abduction treatment (immediate-treatment group) or follow-up alone (active-sonographic-surveillance group). The main outcome measurement was the acetabular inclination angle, measured by radiograph, at 1 year of age. RESULTS: Both groups included 64 newborns, and there was no loss to follow-up. With the exception of a small but statistically significant excess of girls in the active-sonographic-surveillance group, there were no statistically significant differences in baseline characteristics between the 2 groups. The mean inclination angle at 12 months was 24.2 degrees for both groups (difference: 0.1 [95% confidence interval (CI): -0.8 to 0.9]), and all children had improved and were without treatment. The mean alpha angle was 59.7 degrees in the treatment group and 57.1 degrees in the active-surveillance group for a difference of 2.6 degrees evaluated after 1.5 and 3 months (95% CI: 1.8 to 3.4; P < .001). At 1.5 months of age, the hips had improved in all treated children but not in 5 children under active surveillance (P = .06). Among the sonographic-surveillance group, 47% received treatment after the initial surveillance period of 1.5 months. CONCLUSIONS: Active-sonographic-surveillance halved the number of children requiring treatment, did not increase the duration of treatment, and yielded similar results at 1-year follow-up. Given a reported prevalence of 1.3% for mildly dysplastic but stable hips, a strategy of active surveillance would reduce the overall treatment rate by 0.6%. Our results may have important implications for families as well as for health care costs.