Copy number variations (CNVs) have been related to developmental and epileptic encephalopathy (DEE). The 2q24.3 region includes a cluster of genes for voltage-gated sodium channels (SCN) and CNVs in this region cause DEE. However, the long-term course of DEE with a 2q24.3 duplication has not been described. A 20-year-old female developed epileptic encephalopathy in early infancy that was resistant to various antiseizure medications. Her seizures disappeared after starting vitamin B6 therapy. Therefore, her epilepsy was considered pyridoxine-dependent epilepsy. At 16 years old, whole exome sequencing revealed a 2q24.3 microduplication including SCN1A, SCN2A, SCN3A, SCN7A, and SCN9A. Quantitative PCR detected an increased copy number of 1.3 Mb on 2q24.3 involving these genes, but no gene mutation accounting for pyridoxine-dependent epilepsy. Considering that with this duplication she was reported to be seizure-free after infancy, she was able to be off antiseizure medications including vitamin B6. Our case involvingdrug-resistant epilepsy in early infancy had no recurrent seizures during long-term follow up. Detecting CNVs using whole exome sequencing data was useful to identify a 2q24.3 duplication unassociated with pyridoxine-dependent epilepsy, leading to cessation of unnecessary medications.

Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a genetic disorder with several neurological, cutaneous and skeletal manifestations. Epilepsy has been previously reported as a finding in Gorlin-Goltz syndrome but remains ill-described in the context of this disease. We report two new patients with Gorlin-Goltz syndrome featuring epilepsy and review the existing literature on the topic.

We observed that cannabidiol supplements were highly effective in treating an infant boy with drug-resistant early infantile epileptic encephalopathy, eliminating his intractable tonic seizures. The infant began suffering clusters of brief tonic seizures from birth at 39 weeks gestation. EEG showed burst-suppression and seizures could not be controlled by trials of phenobarbital, zonisamide, vitamin B6, clobazam, levetiracetam, topiramate, phenytoin, valproate, high-dose phenobarbital, and ACTH therapy. The boy was discharged from hospital at 130 days of age still averaging tonic seizures 20-30 times per day. We started him on a cannabidiol supplement on day 207, increasing the dosage to 18 mg/kg/d on day 219. His seizures reduced in frequency and completely disappeared by day 234. These effects were maintained, with improved EEG background, even after his other medications were discontinued. Cannabidiol\'s effectiveness in treating drug-resistant epilepsy has been confirmed in large-scale clinical trials in Europe and the United States; however, no such trials have been run in Asia. In addition, no reports to date have documented its efficacy in an infant as young as six months of age. This important case suggests that high-dose artisanal cannabidiol may effectively treat drug-resistant epilepsy in patients without access to pharmaceutical-grade CBD.

Pregnane X receptor (PXR) is the major regulator of xenobiotic metabolism. PXR itself is controlled by various signaling molecules including glucocorticoids. Moreover, negative feed-back regulation has been proposed at the transcriptional level. We examined the involvement of the 3\'-untranslated region (3\'-UTR) of NR1I2 mRNA and microRNAs in PXR- and glucocorticoid receptor (GR)-mediated regulation of NR1I2 gene expression. PXR ligands were found to significantly downregulate NR1I2 mRNA expression in a set of 14 human hepatocyte cultures. Similarly, PXR was downregulated by PCN in the C57/BL6 mice liver. In mechanistic studies with the full-length 3\'-UTR cloned into luciferase reporter or expression vectors, we showed that the 3\'-UTR reduces PXR expression. From the miRNAs tested, miR-18a-5p inhibited both NR1I2 expression and CYP3A4 gene induction. Importantly, we observed significant upregulation of miR-18a-5p expression 6 h after treatment with the PXR ligand rifampicin, which indicates a putative mechanism underlying NR1I2 negative feed-back regulation in hepatic cells. Additionally, glucocorticoids upregulated NR1I2 expression not only through the promoter region but also via 3\'-UTR regulation, which likely involves downregulation of miR-18a-5p. We conclude that miR-18a-5p is involved in the down-regulation of NR1I2 expression by its ligands and in the upregulation of NR1I2 mRNA expression by glucocorticoids in hepatic cells.

New-onset refractory status epilepticus (NORSE) is a rare neurological emergency condition with poor prognosis. A 30-year-old male suddenly had tonic-clonic convulsions seven days after a preceding fever and diarrhea. MRI showed a reversible splenial lesion, and he developed refractory multifocal and generalized seizures in spite of anticonvulsant medication. He was diagnosed with NORSE and received a combination treatment with immunotherapy and targeted temperature management (TTM), which effectively decreased his seizures. This case suggests that even for patients with reversible splenial lesions, NORSE should be considered, and that treatment with immunotherapy and TTM may be effective.

Mounting evidence demonstrates that CYP2B6 plays a much larger role in human drug metabolism than was previously believed. The discovery of multiple important substrates of CYP2B6 as well as polymorphic differences has sparked increasing interest in the genetic and xenobiotic factors contributing to the expression and function of the enzyme. The expression of CYP2B6 is regulated primarily by the xenobiotic receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR) in the liver. In addition to CYP2B6, these receptors also mediate the inductive expression of CYP3A4, and a number of important phase II enzymes and drug transporters. CYP2B6 has been demonstrated to play a role in the metabolism of 2%-10% of clinically used drugs including widely used antineoplastic agents cyclophosphamide and ifosfamide, anesthetics propofol and ketamine, synthetic opioids pethidine and methadone, and the antiretrovirals nevirapine and efavirenz, among others. Significant inter-individual variability in the expression and function of the human CYP2B6 gene exists and can result in altered clinical outcomes in patients receiving treatment with CYP2B6-substrate drugs. These variances arise from a number of sources including genetic polymorphism, and xenobiotic intervention. In this review, we will provide an overview of the key players in CYP2B6 expression and function and highlight recent advances made in assessing clinical ramifications of important CYP2B6-mediated drug-drug interactions.