Antimony ; urine ; Flow Injection Analysis ; Spectrometry, Fluorescence ; methods ; Spectrophotometry, Atomic ; methods

Objective:To analyze the clinical phenotypes and TSC1/TSC2 gene variations in 52 children with tuberous sclerosis complex. Methods:The clinical data of 59 children with tuberous sclerosis complex hospitalized in Linyi People′s Hospital between January 2017 and October 2022 were collected. The analysis of TSC1 and TSC2 gene variations on main family members was performed, and then bioinformatics analysis followed. The positive children were divided into TSC1 gene group and TSC2 gene group, and the difference of clinical characteristics between the two groups was analyzed. Results:Among 59 children, 52 cases were detected TSC1/ TSC2 gene variations (17 cases in the TSC1 gene group and 35 cases in the TSC2 gene group). Of the 52 children, 28 (53.8%) were male, 24 were female (46.2%); 17 (32.7%) were familial cases (10 with TSC1 gene variations and 7 with TSC2 gene variations), 35 (67.3%) were sporadic cases; 46 (88.5%) had hypomelanotic macules, 13 (25.0%) had facial angiofibromas, 5 (9.6%) had shagreen patches, 49 (94.2%) had subependymal nodules/calcifications, 47 (90.4%) had cortical nodules, 2 (3.8%) had subependymal giant cell astrocytomas, 39 (75.0%) had intellectual/developmental disabilities, 49 (94.2%) had epileptic seizures, 8 (15.4%) had cardiac rhabdomyomas, 9 (17.3%) had renal angiomyolipomas, and 4 (7.7%) had retinal hamartomas. Of the 52 children, 49 variations were detected, including 4 large fragment deletion/duplication variations, and 45 point variations; 41 pathogenic variations, 7 likely pathogenic variations, and 1 variation of uncertain significance. In this study, 16 point mutations and 1 large fragment duplication mutation which had not been reported at home and abroad, and 3 high-frequency mutation sites (p.Arg692 *, p.Arg228 *, and p.Arg1200Try) were found. There was a statistically significant difference in the proportion of familial cases [10/17 vs 7/35(20%), χ2=7.838, P=0.005], median onset age of epilepsy [38.0(0.5-134.0) months vs 8.0(0.1-63.0) months, Z=3.506 , P<0.001] and the incidence of developmental retardation/intellectual impairment [8/17 vs 31/35(88.6%), χadj2=8.423, P=0.004] between the TSC1 gene and TSC2 gene groups. Conclusions:Tuberous sclerosis compiex has widespread phenotypes, can affect every body system, especially the skin and nervous system. The pathogenic gene is TSC1/ TSC2. The TSC1 gene group has more familial cases. The TSC2 gene group has an earlier onset age of epilepsy and a higher incidence of developmental retardation/intellectual impairment. In this study, 16 novel point mutations, 1 novel large fragment duplication mutation, and 3 hotspot mutations were identified, expanding the gene variation spectrum of tuberous sclerosis complex.

Objective:To investigate the clinical phenotype and genetic characteristics of infantile epileptic spasm syndrome caused by BRWD3 gene mutation. Methods:Clinical data of a child with BRWD3 related infantile epileptic spasm syndrome who was admitted to Department of Pediatric Neurology of Linyi People′s Hospital on August 2, 2019 were collected and followed up, whole exome sequencing technology and Sanger sequencing were applied to verify the child and his parents, and the pathogenicity of mutation site was analyzed. The studies till June 2023 were searched with keywords of " BRWD3" in both English and Chinese databases of China National Knowledge Infrastructure, Wanfang, Online Mendelian Inheritance in Man, and PubMed. The clinical phenotype and genetic characteristics of patients with BRWD3 related epilepsy were summarized. Results:The patient was a 4 years and 4 months old boy, with a clinical phenotype including severe global development delay, focal seizures (the onset age was 4 months), epileptic spasm (the onset age was 6 months), autism, megacephaly, high forehead as well as hypsarrhythmia. The whole exome sequencing results showed a de novo and frameshift variation c.4318_4319del(p.Q1441Efs*20)(NM_153252) in the BRWD3 gene, and the variation was interpreted as pathogenic (PVS1+PS2+PM2) according to the American College of Medical Genetics and Genomics variant classification criteria and guidelines. A total of 7 English literature articles were retrieved reporting 16 cases of BRWD3 gene related epilepsy in children (including 1 case of infantile epileptic spasm syndrome), and there has been no report in China yet. Totally there were 17 cases of BRWD3 gene related epilepsy including this case. All the cases showed X chromosome dominant inheritance, of whom 15 cases showed minor variations, including 7 missense variations, 3 frameshift variations, 3 splicing variations, 2 nonsense variations, and the remaining 2 cases showed large segment deletions. A total of 15 different variants were found. The phenotypes of the 17 patients mainly included epileptic seizures (17/17), intellectual disability (10/17), motor development disorder (7/17), speech impairment (9/17), megacephaly (8/17), facial malformation (8/17), autism (4/17) and hypotonia (4/17). The common seizure types were found to be focal seizures, occasionally epileptic spasm seizures and tonic seizures. Conclusions:BRWD3 gene variation related epilepsy is an X chromosome dominant genetic disease with a wide clinical phenotype spectrum. BRWD3 gene mutation c.4318_4319del(p.Q1441Efs *20) could cause infantile epileptic spasm syndrome, manifested as severe global developmental delay, epileptic spasm, focal seizures, autism, craniofacial malformation and hypsarrhythmia. This research enriches BRWD3 gene mutation spectrum.

Objective:To summarize the clinical and genetic characteristics of children with epilepsy associated with SCN2A gene variations. Methods:A retrospective study was performed. Eleven children with epilepsy admitted to Department of Pediatric Neurology, Linyi People's Hospital from January 2017 to December 2022 were included; all of them had pathogenic SCN2A gene mutation. Genetic results and clinical data as epileptic seizure type/frequency, intelligence and motor development of these 11 children were collected. Epilepsy-related variations and pathogenesis of SCN2A gene were analyzed, and their correlations with clinical phenotypes in these children were analyzed. Results:Among the 11 patients, 6 had self-limited epilepsy (4 with variation in the intracellular domain and 2 in the transmembrane domain), 1 had febrile convulsion accompanied by childhood absent epilepsy (with variation in the intracellular domain), and 4 had developmental epileptic encephalopathy (2 with variation in the extracellular domain and 2 with variation in the transmembrane domain). SCN2A gene was missense mutation in these 11 children, and the mutation site in 6 children was not reported before. Various forms of video EEG discharge were noted, and 1 child with self-limited epilepsy showed transient multifocal epileptic discharge during frequent seizures. Oxcarbazepine and topiramate were effective for self-limiting epilepsy, and lamotrigine was effective in 1 child with late-onset epileptic encephalopathy. Eleven patients were followed up for (66±32) months; the age ranged from 8 months to 11 years and 6 months at the last follow-up; 10 patients had seizure remission and 1 had uncontrolled seizure. Conclusions:Besides self-limited epilepsy and developmental epileptic encephalopathy, SCN2A gene mutations are also associated with febrile convulsion and childhood absent epilepsy. Phenotypic differences are highly correlated with mutation locations; developmental epileptic encephalopathy associated variants are mostly located in extracellular domains, while self-limited epileptic variants are mostly located in intracellular domains.

Objective:To investigate the clinical phenotype and genetic characteristics of developmental epileptic encephalopathy 18 (DEE18) caused by SZT2 gene variants. Methods:Clinical data of 2 children with SZT2 related DEE18 who visited the Department of Pediatric Neurology, Linyi People′s Hospital in March 2020 and July 2023 were collected. The whole exome sequencing (WES) and Sanger sequencing were applied to verify the child and their parents. SWISS-MODEL software was used to perform protein 3D modeling for the selected SZT2 gene variants. Results:Both of the 2 cases showed severe global developmental delay, epileptic seizures, autism, megacephaly, facial deformity, hypotonia, corpus callosum malformation, persistent cavum septum pellucidum, and slow background activity and focal discharge in video electroencephalography. Case 1 was easy to startle and thin in stature; case 2 had immune deficiency and clustered seizures. WES results showed that case 1 carried a compound heterozygous variant of c.5811G>A (p.W1937X) (paternal) and c.9269delG (p.S3090Ifs *94) (maternal), while case 2 carried a compound heterozygous variant of c.6302A>C(p.H2101P) (paternal) and c.7584dupA (p.E2529Rfs *20) (maternal), the parents of both patients with normal clinical phenotypes. The 4 mutations mentioned above were novel variations that had not yet been reported domestically or internationally. According to the American College of Medical Genetics and Genomics variant classification criteria and guidelines, the p.S3090Ifs *94 variant was interpreted as pathogenic; p.W1937X variant was interpreted as pathogenic; p.E2529Rfs *20 variant was interpreted as likely pathogenic; p.H2101P variant was interpreted as uncertain significance. 3D modeling showed that the variant of p.H2101P resulted in a significant change in the hydrogen bond around the 2 101st amino acid encoded, leading to a decrease in protein stability. The other 3 variants led to early truncation of peptide chain and obvious changes in protein structure. Conclusions:DEE18 caused by SZT2 gene mutation is mainly an autosome recessive genetic disease, and its clinical manifestations include global developmental delay, epileptic seizures, autism, craniofacial malformation, hypotonia, epileptic discharge, corpus callosum malformation, persistent cavum septum pellucidum, shock, small and thin stature, and immune deficiency. Four novel variants related to the SZT2 gene may be the genetic etiology of DEE18 patients in this study.