Mitochondria are dynamic organelles that undergo fusion and fission. These active processes occur continuously and simultaneously and are mediated by nuclear-DNA-encoded proteins that act on mitochondrial membranes. The balance between fusion and fission determines the mitochondrial morphology and adapts it to the metabolic needs of the cells. Therefore, these two processes are crucial to optimize mitochondrial function and its bioenergetics abilities. Defects in mitochondrial proteins involved in fission and fusion due to pathogenic variants in the genes encoding them result in disruption of the equilibrium between fission and fusion, leading to a group of mitochondrial diseases termed disorders of mitochondrial dynamics. In this review, the molecular mechanisms and biological functions of mitochondrial fusion and fission are first discussed. Then, mitochondrial disorders caused by defects in fission and fusion are summarized, including disorders related to MFN2, MSTO1, OPA1, YME1L1, FBXL4, DNM1L, and MFF genes.

Isolated gallbladder injury, secondary to a blunt abdominal trauma, is a rare finding in children.The presence of vague symptoms and the unknown dynamic of the trauma may increase the diagnostic challenge especially in pediatrics.A conservative management has been proposed in some particular cases in adults, but remains controversial in children.We report a case of a 5 year old boy who presented an isolated gallbladder lesion secondary to a blunt abdominal trauma.The surgical treatment was delayed for non-medical reasons, which gave us the possibility to try a conservative approach.

Objective: Evaluate the effect of probiotics association in reducing the total bilirubin level in the serum of neonates with jaundice. Methods: 69 neonates with indirect hyperbilirubinemia were divided randomly into two groups: control and treatment. The control group was treated using phototherapy and the treatment group was treated using phototherapy plus L.Reuteri probiotic. Inclusion criteria: all term newborns admitted for phototherapy for unconjugated hyperbilirubinemia. Exclusion criteria: septic or ill newborn, phenobarbital therapy, transfusion and parents ‘refusal to enter the study. Baseline bilirubin level was obtained prior to initiating phototherapy and then daily for an average of 3 days. Results: Before treatment, the level of bilirubin was similar in the two groups (p>0.05). We noted a more significant difference in bilirubin at day 1 (p=0.000), day 2 (=0.000) and day 3 (p=0.000) during treatment in the probiotic group when compared to the control group. We also noticed a more significant decrease in bilirubin between day 1 and day 2 (p=0.000) and between day 2 and day 3 (p=0.000) in the probiotic group when compared to the control group. Conclusion: The decrease of bilirubin in neonates with jaundice is more rapid and more significant in the group receiving probiotics as an adjuvant to phototherapy in case of presence of incompatibility or not.

Epigenetic modifications of DNA and histone tails are essential for gene expression regulation. They play an essential role in neurodevelopment as nervous system development is a complex process requiring a dynamic pattern of gene expression. Histone methylation is one of the vital epigenetic regulators and mostly occurs on lysine residues of histones H3 and H4. Histone methylation is catalyzed by two sets of enzymes: histone lysine methyltransferases (KMTs) and histone lysine demethylases (KDMs). KMT2 enzymes form a distinct multi-subunit complex known as COMPASS to enhance their catalytic activity and diversify their biologic functions. Several neurodevelopmental syndromes result from defects in histone methylation which can be caused by deficiencies in histone methyltransferases and demethylases, loss of the histone methyltransferase activator TASP1, or derangements in COMPASS formation. In this review article, the molecular mechanism of histone methylation is discussed followed by summarizing clinical syndromes caused by monogenic defects in histone methylation.

The incidence of primary tracheobronchomalacia (TBM) in pediatric patients is 1/2100 and its prevalence in very premature infants with bronchopulmonary dysplasia is 10-46%. We report the case of a 26-week-old baby with recurrent infections and stunting. He was diagnosed for TBM.