Dravet syndrome is a rare and severe type of epilepsy in infants. Approximately, 70-80% of patients with Dravet syndrome have mutations in SCN1A, the gene encoding the alpha-1 subunit of the sodium channel, while some simplex patients have variants in one of several other genes, including but not limited to GABRA1, SCN2A, STXBP1, GABRG2, and SCN1B. In this study, we performed exome sequencing in six patients with SCN1A-negative Dravet syndrome to identify other genes related to this disorder. In one affected individual, we detected a novel de novo heterozygous missense variant, c.695G>A, p.(Arg232Gln), in GABRB3, the gene encoding the β3-subunit of the gamma-aminobutyric acid type A (GABAA) receptor, which mediates inhibitory signaling within the central nervous system. In summary, the data in this study identify GABRB3 as a candidate gene for Dravet syndrome.

Background and PurposeDravet syndrome is a rare and severe type of epilepsy in infants. The heterogeneity in the overall intellectual disability that these patients suffer from has been attributed to differences in genetic background and epilepsy severity.MethodsEighteen Vietnamese children diagnosed with Dravet syndrome were included in this study. SCN1A variants were screened by direct sequencing and multiplex ligation-dependent probe amplification. Adaptive functioning was assessed in all patients using the Vietnamese version of the Vineland Adaptive Behavior Scales, and the results were analyzed relative to the SCN1A variants and epilepsy severity.ResultsWe identified 13 pathogenic or likely pathogenic variants, including 6 that have not been reported previously. We found no correlations between the presence or type of SCN1A variants and the level of adaptive functioning impairment or severity of epilepsy. Only two of nine patients aged at least 5 years had an adaptive functioning score higher than 50. Both of these patients had a low frequency of convulsive seizures and no history of status epilepticus or prolonged seizures. The remaining seven had very low adaptive functioning scores (39 or less) despite the variability in the severity of their epilepsy confirming the involvement of factors other than the severity of epilepsy in determining the developmental outcome.ConclusionsOur study expands the spectrum of known SCN1A variants and confirms the current understanding of the role of the genetic background and epilepsy severity in determining the developmental outcome of Dravet syndrome patients.

Egg whites of salted duck eggs are normally discarded in the separation of egg yolks. Most of the nutritional values of normal duck eggs are still retained in the egg whites of salted duck eggs. To make use of such egg whites, it is necessary to process the egg whites into a protein-rich powder, which can be used as a food processing material. Nevertheless, long-term storage of the egg white powder is challenging because this powder can easily absorb moisture, resulting in physical deteriorations (e.g: colour change), chemical alternation (e.g., protein and lipid degradation), and biological contamination (e.g., growth of yeasts and molds that produce toxic compounds). A study was conducted to test different types of packaging materials includingone-layered Polyethylene (PE) film, two-layered PE film, and three-layered films (PE, AL-Foil, BOPP/PE, Al/PE, BOPP/Al/PE, PET/Al/PE). The result shows that the most suitable packaging material for the protein-rich powder produced from egg whites of salted duck egg was two-layered AI/PE film. The quality of the product stored in AI/PE film package remained nearly unchanged in 12 months, which proved safe to be used as food processing material.