Discovery of pathogenic variants in EFEMP2 and RAG1 and undetectable fetal phenotype: A challenge of prenatal exome sequencing.

BACKGROUND: Exome sequencing in prenatal context confronts with pathogenic variants associated with phenotypes that are not detectable prenatally. MATERIALS AND METHODS: A consanguineous couple was referred at 24 weeks of gestation for prenatal genetic investigations after ultrasonography findings including decreased fetal movements, hypoplastic male external genitalia, retrognathia, prefrontal edema, anomalies of the great vessels with pulmonary atresia and dilated tortuous aorta. RESULT: Prenatal trio exome sequencing identified two homozygous likely pathogenic variants, i.e. a missense in EFEMP2 involved in cutis laxa and a nonsense in RAG1 involved in several types of severe combined immunodeficiency. DISCUSSION: The fetal ultrasonographic phenotype was partially compatible with previously reported prenatal presentations secondary to EFEMP2 biallelic variants, but prenatal presentations have never been reported for RAG1 related disorders because the RAG1 phenotype is undetectable during pregnancy. CONCLUSION: Both EFEMP2 and RAG1 variants were disclosed to the couple because the EFEMP2 variant was considered causative for the fetal ultrasonographic phenotype and the RAG1 variant was considered a finding of strong interest for genetic counselling and monitoring of future pregnancies following the American College of Medical Genetics and Genomics recommendations about the discovery of incidental findings in fetal exome sequencing in prenatal diagnosis.

Preterm birth affects both surfactant synthesis and lung liquid resorption actors in fetal sheep.

INTRODUCTION: After birth, the lungs must resorb the fluid they contain. This process involves multiple actors such as surfactant, aquaporins and ENaC channels. Preterm newborns often exhibit respiratory distress syndrome due to surfactant deficiency, and transitory tachypnea caused by a delay in lung liquid resorption. Our hypothesis is that surfactant, ENaC and aquaporins are involved in respiratory transition to extrauterine life and altered by preterm birth. We compared these candidates in preterm and term fetal sheeps. MATERIALS AND METHODS: We performed cesarean sections in 8 time-dated pregnant ewes (4 at 100 days and 4 at 140 days of gestation, corresponding to 24 and 36 weeks of gestation in humans), and obtained 13 fetal sheeps in each group. We studied surfactant synthesis (SP-A, SP-B, SP-C), lung liquid resorption (ENaC, aquaporins) and corticosteroid regulation (glucocorticoid receptor, mineralocorticoid receptor and 11-betaHSD2) at mRNA and protein levels. RESULTS: The mRNA expression level of SFTPA, SFTPB and SFTPC was higher in the term group. These results were confirmed at the protein level for SP-B on Western Blot analysis and for SP-A, SP-B and SP-C on immunohistochemical analysis. Regarding aquaporins, ENaC and receptors, mRNA expression levels for AQP1, AQP3, AQP5, ENaCα, ENaCß, ENaCγ and 11ßHSD2 mRNA were also higher in the term group. DISCUSSION: Expression of surfactant proteins, aquaporins and ENaC increases between 100 and 140 days of gestation in an ovine model. Further exploring these pathways and their hormonal regulation could highlight some new explanations in the pathophysiology of neonatal respiratory diseases.

Early elevated alkaline phosphatase as a surrogate biomarker of ongoing metabolic bone disease of prematurity.

Very low birth weight (VLBW) neonates present a high risk of metabolic bone disease (MBD). Our main objective was to determine the easiest way to make an early diagnosis of this disease by identifying surrogate biomarkers before any radiological signs occurred. We conducted in our NICU a 6-month observational prospective study, with inclusion of all singleton VLBW neonates. We collected clinical and biological data, and nutritional intakes during hospitalization. We defined biological MBD (bMBD) as alkaline phosphatase (ALP) levels superior to 600 UI/L at day of life 30 (DOL30) and performed a case-control analysis. Nine out of 30 patients (30%) exhibited bMBD. All have extremely low birth weight and were significantly younger in gestational age (GA) and smaller at birth. There was no statistically significant difference in nutritional intake between bMBD and control groups. In the bMBD group, phosphatemia was lower since DOL3. ALP was already significantly higher at DOL15, and way beyond normal range. CONCLUSIONS: Our results showed that even the strict respect of nutritional guidelines cannot completely prevent bMBD in high-risk patients and suggest that an early screening from DOL15, with ALP levels greater than 500 UI/L, could be sufficient for detection of upcoming MBD. WHAT IS KNOWN: • Metabolic bone disease of prematurity (MBD) definition is not consensual, but biological changes appear earlier than radiological signs of rickets. • MBD management relies on biological evidence. Treatment is based on phosphate and/or calcium and calcitriol supplementation. WHAT IS NEW: • Studying phosphocalcic biological assessment in very low birth weight neonates, we showed respect of nutritional guidelines could not protect from biological MBD. • Increase in alkaline phosphatase (ALP), about 500 UI/l at day of life 15, could be a biomarker of MBD with no need of X-ray evaluation and sufficient to begin a treatment to prevent osteopenia.

Glucocorticoid-Induced Hyperinsulinism in a Preterm Neonate with Inherited ABCC8 Variant.

Glucose homeostasis is a real challenge for extremely preterm infants (EPIs) who have both limited substrate availability and immature glucose metabolism regulation. In the first days of life, EPIs frequently develop transient glucose intolerance, which has a complex pathophysiology that associates unregulated gluconeogenesis, immature insulin secretion, and peripheral insulin resistance. In this population, glucocorticoid therapy is frequently administrated to prevent severe bronchopulmonary dysplasia. During this treatment, glucose intolerance classically increases and may lead to hyperglycemia. We report a case of neonatal hypoglycemia that was concomitant to a glucocorticoids administration, and that led to a congenital hyperinsulinism diagnosis in an EPI with a heterozygous ABCC8 variant. The variant was inherited from his mother, who had developed monogenic onset diabetes of the youth (MODY) at the age of 23. ABCC8 encodes a beta-cell potassium channel unit and causes congenital hyperinsulinism or MODY depending on the mutation location. Moreover, some mutations have been observed in the same patient to cause both hyperinsulinism in infancy and MODY in adulthood. In our case, the baby showed repeated and severe hypoglycemias, which were undoubtedly time-associated with the betamethasone intravenous administration. This hyperinsulinism was transient, and the infant has not yet developed diabetes at three years of age. We take the opportunity presented by this unusual clinical presentation to provide a review of the literature, suggesting new insights regarding the pathophysiology of the beta-pancreatic cells' insulin secretion: glucocorticoids may potentiate basal insulin secretion in patients with ABCC8 mutation.

Small for Gestational Age Preterm Neonates Exhibit Defective GH/IGF1 Signaling Pathway.

Objective: To investigate the impact of fetal growth restriction (FGR) on hormonal regulation of post-natal growth and glucose metabolism [via insulin and growth hormone (GH)/Insulin-like Growth factor 1 (IGF1) axis pathways] in small for gestational age (SGA) neonates. Methods: We conducted a monocentric observational prospective comparative study on 73 singleton babies born with a weight inferior to 2,000 g. We analyzed auxological (weight, height and head circumference), and hormonal (GH, IGF1, and insulin plasma concentrations) data comparing SGA and appropriate for gestational age (AGA) neonates, between day 1 and 60. Results: One third (23/73) of the neonates were SGA. Twenty-five percent (18/73) required insulin for idiopathic hyperglycemia of prematurity and were smaller in weight and head circumference at discharge. In the SGA group compared with the AGA group, GH plasma concentrations were higher at day 3 (70.1 vs. 38.0 mIU/L) and IGF1 plasma concentrations were higher at day 10 (29.0 vs. 18.7 ng/ml). Conclusions: SGA neonates displayed resistance to GH and IGF1, concomitant to insulin resistance. This could partially explain the initial defective catch-up growth and, later in life, the higher prevalence of metabolic syndrome in this population.

Perception of medical education by learners and teachers during the COVID-19 pandemic: a cross-sectional survey of online teaching.

COVID-19 lockdowns have deeply impacted teaching programs. Online teaching has suddenly become the main form of medical education, a form that may be used as long as the pandemic continues. We aimed at analyzing how online teaching was perceived by both teachers and learners to help determine how to adapt curricula in the next few years. An anonymous cross-sectional survey of medical students, pediatric residents, neonatal fellows, and their respective teachers was conducted between June and August 2020 to assess feelings about quality, attendance, equivalence, and sustainability of online teaching programs. 146 Students and 26 teachers completed the survey. 89% of students agreed that the offered online teaching was an appropriate way of teaching during the pandemic. Less than half of learners and teachers felt they have received or provided a training of an equivalent level and quality as in usual courses. About one-third thought that this online teaching should continue after the crisis ends. Medical school students had significantly more mixed opinions on online teaching than residents and fellows did. Attendance of learners significantly improved with synchronous online classes (p < 0.001), and among more advanced learners (p < 0.002). Our study is the first of this kind to assess simultaneously the feelings of learners at different levels (medical students, residents, and fellows) and their respective teachers of pediatric on programs taught online. It showed that online programs were perceived as appropriate ways of teaching during the COVID pandemic. Further studies are, however, needed to assess the efficacy of such teaching methods on medical skills and communication capabilities.