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.

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 explore the clinical and genetic characteristics of five children with epilepsies due to variants of SCN8A gene. Methods:Clinical data of five children (four males and one female) admitted to Linyi People′s Hospital due to hereditary epilepsies between August 2015 and August 2022 were collected. Whole exome sequencing was carried out for these children, and candidate variants were verified by Sanger sequencing.Results:All of the five children were found to harbor variants of the SCN8A gene. Case 1, who had benign familial infantile epilepsy, inherited a known pathogenic c. 4840A>G variant from his father with similar symptoms. Cases 2 to 4 had presented with intermediate epilepsy. Among these, case 2 has harbored a de novo c. 3967G>A variant which was rated as pathogenic (PS1+ PS2+ PM1+ PM2_Supporting+ PP3) based on the guidelines from the American College of Medical Genetics and Genomics. Cases 3 and 4 were found to respectively harbor a de novo c. 415A>T and a c. 4697C>T variant, which were both rated as likely pathogenic (PS2+ PM1+ PM2_Supporting+ PP3). Case 5, who had early-onset infantile epileptic encephalopathy transformed into Lennox Gastaut-like syndrome, has harbored a de novo c. 5615G>A variant, which was known to be pathogenic. The children had their age of onset ranging from 2 to 14 months, and all had focal seizures and generalized tonic clonic seizures. Four children (cases 1, 2, 3 and 5) had cluster seizures, four (cases 1 to 4) had become seizure-free after single or dual treatment and showed normal growth and development, whilst case 5 was drug-resistant and showed severe developmental retardation. Conclusion:The five children had new features such as cluster seizures, occasional benign seizures in adulthood, and intermediate epilepsy which are prone to relapse after discontinuation of medication, which may be attributed to the pathogenic variants of the SCN8A gene.

Objective:To explore the clinical manifestations and pathogenic variant in a family with epilepsy, developmental delay and brain deformity.Methods:Clinical data of the child and his family members who had visited the Department of Pediatrics, Linyi People's Hospital on July 2, 2022 were collected. The child, his sister and parents were subjected to high-throughput sequencing, and the result was verified by Sanger sequencing.Results:The child was a 6-year-old boy with developmentally delay and had epileptic seizures with fever sensitivity for four years. Cranial imaging showed brain dysplasia, while the video electroencephalogram showed abnormal discharge. High-throughput sequencing showed the child has harbored a heterozygous c. 5G>T (p.Arg2Leu) variant of TUBB2A gene, which was unreported previously. His sister also carried the variant and had similar clinical manifestations, whilst his parents were of the wild-type and had normal clinical phenotypes. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PS2+ PM2_Supporting+ PM5+ PP1+ PP2+ PP3). Conclusion:The heterozygous c. 5G>T (p.Arg2Leu) variant of the TUBB2A gene, in the form of gonadal mosaicism, probably underlay the disorders in this family.

Objective:To explore the clinical features and genetic etiology of a child with SPONASTRIME dysplasia (SD).Methods:A 9-month-old female who had presented at the Linyi People′s Hospital in August 2022 for short stature was selected as the study subject. Clinical data of the child were collected, and whole exome sequencing (WES) was carried out. Sanger sequencing was used for validating the candidate variants.Results:The child has manifested short stature, mid-face hypoplasia, joint laxity, internal knee rotation, irregularities in the metaphysis of long bones, and flat and concave lumbar vertebrae. WES revealed that she has harbored compound heterozygous variants of the TONSL gene, namely c.3088G>T (p.Glu1030*) and c. 3053G>A (p.Arg1018His), which were inherited from her phenotypically normal parents. Neither variant was reported previously. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c. 3088G>T variant was classified as likely pathogenic (PVS1+ PM2_Supporting), whilst the c. 3053G>A was classified as a variant of uncertain significance (PM2_Supporting+ PM3+ PP3). Conclusion:The c. 3088G>T and c. 3053G>A compound heterozygous variants of the TONSL gene probably underlay the pathogenesis in this patient. Above finding has facilitated the clinical diagnosis and genetic counseling for her family.

Objective:To explore the clinical phenotype and genetic characteristics of children with childhood absence epilepsy caused by KMT2E gene variants. Methods:The clinical data of 1 case of KMT2E gene variant-associated childhood absence epilepsy admitted to the Department of Pediatric Neurology of Linyi People′s Hospital in January 2023 were collected and followed up, and the child and her family were genetically examined by using whole-exome sequencing and Sanger sequencing, and the pathogenicity of mutation loci was analyzed. The Online Mendelian Inheritance in Man, Human Gene Mutation Database, PubMed database, China National Knowledge Infrastructure, and Wanfang database were consulted with the search term " KMT2E" to summarize the clinical phenotype and genetics of the children with epilepsy associated with KMT2E gene variant. Results:The child is a female, presented with typical absence seizures at the age of 3 years and 8 months, with normal development, video electroencephalogram showing widespread spikes and slow waves around 3 Hz accompanied by typical absence seizures. Seizures decreased after valproic acid was applied at full dosage, and were controlled after combination with lamotrigine. Her clinical diagnosis of childhood absence epilepsy was made. The results of whole-exome sequencing showed that the child had a de novo frameshift variant c.2404dup (p.Arg802Lysfs *8) in the KMT2E gene (NM_182931.3), which had not yet been reported domestically or internationally. The c.2404dup variant was interpreted as a pathogenic variant (PVS1+PS2_Supporting+PM2_Supporting) according to the American Society of Medical Genetics and Genomics variant classification criteria and guidelines. Her parents, older brother and younger sister did not carry the variant and had a normal clinical phenotype. A total of 22 patients with epilepsy associated with KMT2E gene variants were retrieved (including this case, a total of 23 cases), including 10 females and 13 males. All of them were autosomal dominant inheritance, with 20 minor variations, including 8 frameshift variants, 7 missense variants, 2 splicing variants, 2 nonsense variants, 1 synonymous variant, and the remaining 3 cases had large fragment deletions (including 2 cases of the whole gene). Clinical manifestations mainly included epileptic seizures (5 cases of absence seizures, 7 cases of focal seizures with or without secondary tonic-clonic seizures, 9 cases of tonic-clonic seizures, 1 case of spasm seizures, 1 case of myoclonic seizures, tonic seizures, and atonic seizures, 3 cases of epileptic status, and 5 cases of refractory epilepsy, with the onset age of epilepsy ranging from neonatal to adolescence), mental retardation (21/23 cases, 4 mild, 5 moderate, and 5 severe), peculiar facial features (11/23), and autism (3/23), etc. Conclusion:KMT2E gene variant-associated epilepsy is an autosomal dominant disorder with a wide spectrum of clinical phenotypes, and the novel variant c.2404dup in the KMT2E gene identified in the present study can lead to childhood absence epilepsy, which enriches the spectrum of mutations and clinical phenotype of the KMT2E gene.

OBJECTIVE: To explore the clinical features and genetic etiology of a child with Multiple congenital malformations-hypotonia-epilepsy syndrome type 3 (MCAHS3) and provide prenatal diagnosis for her parents. METHODS: A female child who had presented at Linyi People's Hospital on 27 July 2022 for recurrent convulsions for over 4 years was selected as the study subject. Clinical data of the child were collected. Peripheral blood samples were taken from the child and her parents and subjected for whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing. Prenatal diagnosis was carried out on amniotic fluid sample at 18 weeks' gestation. Bioinformatic software was used to analyze the pathogenicity of the protein model for the variant loci. RESULTS: The child was a 4-year-old female with frequent seizures, peculiar facial appearance, hypotonia and severe developmental delay. Genetic analysis revealed that she has harbored compound heterozygous variants of the PIGT gene, namely c.1126del (p.H376Tfs*56) and c.1285G>C (p.E429Q), which were respectively inherited from her mother and father. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.1126del (p.H376Tfs*56) variant was predicted to be pathogenic (PVS1+PM2_Supporting+PM4), and c.1285G>C (p.E429Q) variant was predicted to be likely pathogenic (PM2_Supporting+PM3+PM4). Prenatal diagnosis suggested that the fetus also harbored the same compound heterozygous variants, and the pregnancy was terminated with induced labor. CONCLUSION The c.1126del (p.H376Tfs*56) and c.1285G>C (p.E429Q) compound heterozygous variants of the PIGT gene probably underlay the MCAHS3 in this patient, and prenatal diagnosis has prevented birth of further affected child in this family.
Humans ; Female ; Child ; Pregnancy ; Child, Preschool ; Muscle Hypotonia/genetics* ; Prenatal Diagnosis ; Computational Biology ; Epileptic Syndromes ; Facies

Objective:To analyze the clinical phenotype and gene sequencing results of a child with hyperekplexia, and to clarify her genetic etiology.Methods:The clinical information of the child was collected, and the whole exome sequencing of the child and her parents was performed. The suspected pathogenic variants were verified by Sanger sequencing and bioinformatics analysis.Results:There was a 12 years old girl, who was hospitalized in the Department of Pediatric Neurology of Linyi People′s Hospital because of "paroxysmal limb stiffness for more than 11 years and aggravated for half a month" on July 4, 2022. The girl showed exaggerated startle reflexes and generalized siffness in response to external sudden, unexpected stimuli, occasionally accompanied by apnea and cyanosis, frequent attacks occurred several times a day, lasting for 1-30 minutes, and early head and abdomen flexion can be relieved. She showed normal growth and development, no abnormality in brain magnetic resonance imaging and video electroencephalogram during seizure. The whole exome sequencing showed that there was a missense heterozygous mutation c.643T>C(p.W215R) in the SLC6A5 gene of the child. Neither of the parents carried this mutation, which was a novel and de novo variant. According to the guidelines of American College of Medical Genetics and Genomics, this variant was a likely pathogenic variant [PS2: de novo (both maternity and paternity confirmed) in the patient with the disease and no family history; PM2: undetected variants in the normal population; PP3: multiple softwares predicted that this mutation would have harmful effects on genes or gene products], and highly conserved. Swiss modeling found that the hydrogen bond of the modified amino acid also changed. Conclusions:Hyperekplexia is relatively rare and prone to misdiagnosis. The main clinical features are excessive startle reflexes (limb shaking, or jumping) to unexpected external stimuli, resulting in overall stiffness, normal growth and development, and normal video electroencephalogram during the seizure. The likely pathogenic heterozygous missense variant c.643T>C (p.W215R) of SLC6A5 gene is the genetic cause of this case.

Objective:To analyze the clinical characteristics of a child with developmental epileptic encephalopathy caused by NR4A2 gene mutation, and to summarize the clinical phenotypes and genotypes to improve the clinician′s understanding of this disease. Methods:The clinical data of a child with developmental epileptic encephalopathy admitted to Linyi People′s Hospital in August 2022 were collected, video electroencephalogram, craniocerebral magnetic resonance imaging and family whole exon sequencing were improved, and the suspected mutation sites were verified by Sanger sequencing. Relevant literature was consulted to summarize the clinical phenotypes and genetic characteristics of nervous system diseases caused by NR4A2 gene. Results:It was found that there was a heterozygous missense mutation at the locus c.866G>A (p.A289H) of NR4A2 gene in the child, which was a de novo mutation, and both parents were wild type. According to the American Society of Medical Genetics and Genomics variation classification, it was assessed as a suspected pathogenic variation. Through literature review, there were 16 related cases reported internationally, with clinical phenotypes including mental retardation/mental retardation, language disorders, seizures, muscle tone changes and different psychological and behavioral problems. Conclusions:The NR4A2 gene is not only associated with dopa responsive disorders, but also with neurological development, intellectual impairment, language development delay, and epilepsy. The mutation of NR42A gene c.866G>A (p.A289H) is the genetic cause of the patient, and the detection of this locus expands the NR4A2 gene spectrum. NR4A2 gene is one of the pathogenic genes of developmental epileptic encephalopathy.

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.