De Novo Variant in the KCNJ9 Gene as a Possible Cause of Neonatal Seizures.

BACKGROUND: The reduction in next-generation sequencing (NGS) costs allows for using this method for newborn screening for monogenic diseases (MDs). In this report, we describe a clinical case of a newborn participating in the EXAMEN project (ClinicalTrials.gov Identifier: NCT05325749). METHODS: The child presented with convulsive syndrome on the third day of life. Generalized convulsive seizures were accompanied by electroencephalographic patterns corresponding to epileptiform activity. Proband WES expanded to trio sequencing was performed. RESULTS: A differential diagnosis was made between symptomatic (dysmetabolic, structural, infectious) neonatal seizures and benign neonatal seizures. There were no data in favor of the dysmetabolic, structural, or infectious nature of seizures. Molecular karyotyping and whole exome sequencing were not informative. Trio WES revealed a de novo variant in the KCNJ9 gene (1:160087612T > C, p.Phe326Ser, NM_004983), for which, according to the OMIM database, no association with the disease has been described to date. Three-dimensional modeling was used to predict the structure of the KCNJ9 protein using the known structure of its homologs. According to the predictions, Phe326Ser change possibly disrupts the hydrophobic contacts with the valine side chain. Destabilization of the neighboring structures may undermine the formation of GIRK2/GIRK3 tetramers necessary for their proper functioning. CONCLUSIONS: We believe that the identified variant may be the cause of the disease in this patient but further studies, including the search for other patients with the KCNJ9 variants, are needed.

The newborns Torque teno virus dynamics depending on the term, feeding type and maternal viral load.

The first weeks of life are extremely important for the development of the immunity-virome interaction that affects human health in adulthood. In this study we analyzed Torque teno virus (TTV) dynamics during the first weeks of life in the full-term/premature infants in relation with the maternal TTV load and the type of feeding. 152 infants aged 1-14 weeks (63 full-term and 89 premature) and 33 mother-child pairs were analyzed for the whole blood TTV load by qPCR with test sensitivity of 1000 viral copies/ml. 50 infants were retested (at 2-11 time points) for TTV dynamics data. All one-week babies (n = 71) from TTV-positive mothers were TTV-negative, consistently with the previous findings of the lack of transplacental transmission of the virus. TTV was not detectable in newborns under two weeks of age. Most infants are TTV-positive by 14 weeks of age. Whole blood TTV load does not show significant correlation with full-term/prematurity, maternal TTV load, or feeding type. Keywords: Torque teno virus; transfusion-transmitted virus; commensal virus; TTV; viral load dynamics; TORCH infections; full-term and premature babies; breastfeeding; virome.

[Transient hyperinsulinism in neonates].

Congenital hyperinsulinusm is rare disease characterized high secretion of insulin by pancreatic beta cells leading to the development of hypoglycemia. Persistent and transient forms of hyperinsulinism are distinguished. Transient hyperinsulinism are the most common cause of severe hypoglycemia in newborns. The etiology of this disease is not known. There are risk factors for the development of transient hyperinsulinism: asphyxia at birth, prematurity, maternal diabetes, low or large weight by gestation. Hypoglycemia with hyperinsulinism is severe. Therefore, early diagnosis and therapy especially during the neonatal period, are necessary.The article describes 3 clinical cases of transient hyperinsulinism in children with different gestational age and concomitant pathology. All children recevied insulinostatic therapy with diazoxide with a positive effect: euglycemia without glucose requirement . In all children, therapy was completed subsequently. At the time of publication of the article, the physical and psychomotor development of children is normal.

Oxysterol/chitotriosidase based selective screening for Niemann-Pick type C in infantile cholestasis syndrome patients.

BACKGROUND: Niemann-Pick disease type C (NP-C) is an inherited neurodegenerative disease (1 per 100 000 newborns) caused by NPC proteins impairment that leads to unesterified cholesterol accumulation in late endosomal/lysosomal compartments. To date the NP-C diagnostics is usually based on cholesterol detection in fibroblasts using an invasive and time-consuming Filipin staining and we need more arguments to widely introduce oxysterols as a biomarkers in NP-C. METHODS: Insofar as NP-C represents about 8% of all infant cholestases, in this prospective observational study we tried to re-assess the specificity plasma oxysterol and chitotriosidase as a biochemical screening markers of NP-C in children with cholestasis syndrome of unknown origin. For 108 patients (aged from 2 weeks to 7 years) the levels of cholestane-3ß,5α,6ß-triol (C-triol) and chitotriosidase (ChT) were measured. For patients with elevated C-triol and/or ChT the NPC1 and NPC2 genes were Sanger-sequenced and 47 additional genes (from the custom liver damage panel) were NGS-sequenced. RESULTS: Increased C-triol level (> 50 ng/ml) was detected in 4 (of 108) infants with cholestasis syndrome of unknown origin, with following molecular genetic NP-C diagnosis for one patient. Plasma cholesterol significantly correlates with C-triol (p < 0.05). NGS of high C-triol infants identified three patients with mutations in JAG1 (Alagille syndrome) and ABCB11 (Byler disease) genes. Increased ChT activity was detected in 8 (of 108) patients with various aetiologies, including NP-C, Byler disease and biliary atresia. CONCLUSION: Combined analysis of ChT activity and C-triol levels is an effective method for identifying NP-C.

Torque teno virus dynamics during the first year of life.

BACKGROUND: Torque teno virus is a small chronically persisting circular negative ssDNA virus reaching near 100% prevalence. It is reported to be a marker for immune function in immunocompromised patients. The possibility of vertical maternal-fetal transmission remains controversial but incidence rate of TTV DNA in children increased with age. TTV dynamics well studied for allogeneic hematopoietic stem cell transplantation as a predictor of post-transplant complications but there is no viral proliferation kinetics data for other patient groups or healthy individuals. The aim of this study was to determine TTV dynamics during the first year of life of healthy infants. METHODS: Ninety eight clinically healthy breastfeeding infants (1-12 months of age) were analyzed by quantitative PCR for the whole blood TTV load with the test sensitivity of about 1000 viral copies per milliliter of blood (total number of samples including repeatedly tested infants was 109). RESULTS: 67% of all analyzed samples were TTV-positive demonstrating significant positive correlation between age and TTV load (r = 0.81, p < 0.01). CONCLUSIONS: This is the first study to suggest that viral load increases during the first year of life reaching a plateau after 6 months with strong proliferation for the first 60 days. Our data well correlates with TTV dynamics in patients following allogeneic hematopoietic stem cell transplantation.