Genotypic and phenotypic characteristics of sodium channel-associated epilepsy in Chinese population.

Variants in voltage-gated sodium channel (VGSC) genes are implicated in seizures, epilepsy, and neurodevelopmental disorders, constituting a significant aspect of hereditary epilepsy in the Chinese population. Through retrospective analysis utilizing next-generation sequencing (NGS), we examined the genotypes and phenotypes of VGSC-related epilepsy cases from a cohort of 691 epilepsy subjects. Our findings revealed that 5.1% of subjects harbored VGSC variants, specifically 22 with SCN1A, 9 with SCN2A, 1 with SCN8A, and 3 with SCN1B variants; no SCN3A variants were detected. Among these, 14 variants were previously reported, while 21 were newly identified. SCN1A variant carriers predominantly presented with Dravet Syndrome (DS) and Genetic Epilepsy with Febrile Seizures Plus (GEFS + ), featuring a heightened sensitivity to fever-induced seizures. Statistically significant disparities emerged between the SCN1A-DS and SCN1A-GEFS+ groups concerning seizure onset and genetic diagnosis age, incidence of status epilepticus, mental retardation, anti-seizure medication (ASM) responsiveness, and familial history. Notably, subjects with SCN1A variants affecting the protein's pore region experienced more frequent cluster seizures. All SCN2A variants were of de novo origin, and 88.9% of individuals with SCN2A variations exhibited cluster seizures. This research reveals a significant association between variations in VGSC-related genes and the clinical phenotype diversity of epilepsy subjects in China, emphasizing the pivotal role of NGS screening in establishing accurate disease diagnoses and guiding the selection of ASM.

Uniparental Disomy of Chromosome 15 in Two Cases by Chromosome Microarray: A Lesson Worth Thinking.

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are neurogenetic disorders caused by loss of function of the imprinted genes at 15q11q13. A 5-7 Mb paternal/maternal deletion of chromosomal region 15q11.2q13 is the major genetic cause of PWS/AS, but in a small group of patients, the PWS/AS phenotype can result from maternal/paternal uniparental disomy (UPD) of chromosome 15. Various mechanisms leading to UPD include gametic complementation, trisomy rescue, and compensatory UPD, which can be inferred from the pattern of uniparental heterodisomy (heteroUPD) or uniparental isodisomy (isoUPD). However, heteroUPD and isoUPD, especially mixed heteroUPD and isoUPD, are very rare in patients with PWS/AS. Here, we report 2 children with PWS/AS caused by mixed segmental heteroUPD 15 and isoUPD 15 which failed to be identified by chromosome microarray (CMA) but could be detected by other molecular genetic methods. The present report unravels the mechanism of mixed iso/heteroUPD 15 in PWS/AS and phenotype-genotype correlations. Moreover, our study suggests that CMA is prone to misdiagnosis for imprinting disorders such as PWS/AS, though it is considered a highly useful tool for copy number variations. As a result, other molecular detection methods, such as methylation analysis and STR marker analysis for UPD, should be supplementary used in this situation.

Anti-oxidation and Antiapoptotic Effects of Chondroitin Sulfate on 6-Hydroxydopamine-Induced Injury Through the Up-Regulation of Nrf2 and Inhibition of Mitochondria-Mediated Pathway.

The purpose of the study was to investigate the protective effect and molecular mechanism of chondroitin sulfate (CS) against 6-hydroxydopamine (6-OHDA) induced toxicity in the human neuroblastoma cell line SH-SY5Y. The results showed that CS could protect SH-SY5Y cells against 6-OHDA-induced injury. The subsequent mechanism study showed that the anti-oxidation of CS may partly be mediated through inhibiting the intracellular reactive oxygen species overproduction, recovering the reduction of nuclear NF-E2-related factor-2 (Nrf2) expression and the reduction of antioxidants activity induced by 6-OHDA. Furthermore, CS pretreatment significantly attenuated 6-OHDA-induced cell apoptosis and nuclear condensation. 6-OHDA-induced dysfunctions, including the decrease of mitochondrial membrane potential (ΔΨm), increase of intracellular free Ca(2+), imbalance of Bcl-2/Bax ratio, release of Cyt-c from the mitochondria and activation of caspase-3 and caspase-9 were attenuated by CS pretreatment, which demonstrated that CS suppressed 6-OHDA-induced apoptosis in SH-SY5Y cells possibly through mitochondria protection. These results suggest that CS exhibits anti-oxidation through the up-regulation of Nrf2 along with endogenous antioxidant, and reduces apoptosis via inhibiting the mitochondrial pathway to protect SH-SY5Y cells damaged by 6-OHDA.

Establishment of iPS cell line (SDQLCHi080-A) from a patient with GM1 gangliosidosis due to GLB1 mutation.

GM1 gangliosidosis is an autosomal recessive lysosomal storage disorder caused by defects in the beta-galactosidase (GLB1) gene, which results in accumulation of GM1 gangliosides and related glycoconjugates in the lysosomes leading to lysosomal swelling, cellular damage, and organ dysfunction. We generated SDQLCHi080-A cell line from a patient with GM1 gangliosidosis carrying mutations of c.523C > T and c.574T > C > T in the GLB1 gene. The cell line exhibited typical iPSC morphology, expressed high levels of stemness markers, exhibited normal karyotype, and has the capability to differentiate into three germ layers. This cell line could provide a useful GM1 gangliosidosis model in vitro for further study.

Generation and characterization of an induced pluripotent stem cell (iPSC) line SDQLCHi063-A from peripheral blood mononuclear cells of a patient with Maturity-onset diabetes of the young type 2 carrying GCK exon 1 deletion.

Maturity-onset diabetes of the young type 2 (MODY2) is an autosomal dominant disorder caused by mutations in the GCK gene. It is characterized by a non-progressive slight increase in glycosylated hemoglobin (HbA1c), and mildly raised fasting glucose. Here, we generated an induced pluripotent stem cell line SDQLCHi063-A from a five-year-old boy with MODY2 carrying exon 1 deletion of the GCK gene (OMIM*138079). The iPSC line carries original gene mutation, expresses pluripotency markers, has normal karyotype and differentiated spontaneously in the three germ layers.

Establishment of iPS cell line (SDQLCHi061-A) from a patient with carbamoylphosphate synthetase I deficiency due to CPS1 mutation.

The induced pluripotent stem cells (iPSCs) line was generated using peripheral blood mononuclear cells (PBMCs) from a patient with compound heterozygous mutation of c.2374A > G/p.M792V and c.3949C > T/p.R1317W in the CPS1 gene by non-integrating vectors. The expression of pluripotency markers, potential for in vitro trilineage differentiation and exhibiting normal karyotype were demonstrated in the SDQLCHi061-A cell line. This cell line could provide a useful CPS1D model in vitro for further study.

Generation of a human induced pluripotent stem cell line (SDQLCHi057-A) from an Isovaleric aciduria patient carrying novel compound heterozygous mutations in the IVD gene.

Isovaleric acidemia (IVA; OMIM ID#243500) is an inborn error of leucine metabolism caused by a deficiency of isovaleryl-CoA dehydrogenase (IVD). In this study, we generated a human induced pluripotent stem cell line (hiPSCs) SDQLCHi057-A from a 2-year-7-month old boy with IVA carrying two heterozygous missense mutations c.215A > G (p.N72S) and c.883A > G (p.M295V) of the IVD gene. Patient-specific hiPSCs provide a proper model for further understanding this rare disease.

Establishment of a non-integrated iPS cell line (SDQLCHi072-A) from a patient suffered from AUTS2 syndrome.

In this study, PBMCs used in reprogramming were from a boy suffered from AUTS2 syndrome confirmed by clinical and genetic diagnosis. iPSCs were established by non-integrated method, which carried AUTS2 heterozygous mutation. The established iPSCs presented similar appearance and expressed pluripotent markers in mRNA and protein level. Additionally, the iPSCs possessed favorable differentiative capacity in vivo and normal karyotype. This is an effective potential model for the study about AUTS2 syndrome and the screen about drug therapy.

Establishment of a non-integrated iPSC (SDQLCHi068-A) line derived from a patient with autosomal dominant immunodeficiency-14A carrying a heterozygous mutation (c.3061G>A) in PIK3CD gene.

Phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit delta (PIK3CD) gene (OMIM#602839) encodes the p110δ catalytic subunit, mainly expressed in immune cells, and is associated with autosomal dominant immunodeficiency-14A with lymphoproliferation (IMD14A, #615513). We generated a human iPS cell line from a 50-month-old boy with IMD14A carrying a heterozygous mutation (c.3061G>A, p.E1021K) in PIK3CD gene. This cell line retains the original mutation site and shows differentiation potential towards three germ layers in vitro, which can be used as a disease model for research.

Human induced pluripotent stem cell line (SDQLCHi064-A) derived from a patient with Canavan disease carrying c.556_559dup GTTC and c.919delA mutations in the ASPA gene.

Canavan disease (CD, OMIM# 271900) is an autosomal recessive neurodegenerative disorder caused by homozygous or compound heterozygous mutations in ASPA gene, which result in catalytic deficiency of the aspartoacylase enzyme and the accumulation of N-acetylaspartic acid (NAA). Clinical presentation varies according to the age of disease onset. Here, we generated a human induced pluripotent stem cell line (hiPSCs) SDQLCHi064-A from a 5-month old boy with CD carrying two novel frame shift mutations c.556_559dupGTTC (p.L187Rfs*5) and c.919delA (p.S307Vfs*24) of the ASPA gene, in order for us to better understanding the disease.

Establishment of a non-integrated iPSC line (SDQLCHi043-A) from a male infant with propionic acidemia carrying compound heterozygote mutations in PCCB gene.

In this study, peripheral blood mononuclear cells were contributed from a male infant with propionic acidemia (PA) verified by clinical and genetic diagnosis, who inherited compound heterozygous mutations in the propionyl-CoA carboxylase subunit beta (PCCB) gene. Here, this iPS was generated by non-integrated episomal vectors with SOX2, BCL-XL, OCT4, C-MYC and OCT4. Also, this iPSC line exhibited the morphology of pluripotent stem cells, upward mRNA and protein expression of pluripotency markers, conspicuous in vitro differentiation potency and regular karyotype, and carried PCCB gene mutations, which provided an excellent model for the research and drug screening of PA.

An induced pluripotent stem cell line (SDQLCHi062-A) from a patient carrying a mutation in the PAX2 gene.

Focal segmental glomerulosclerosis 7 (FSGS7, # 616002) is a condition marked by significant proteinuria with or without features of nephrotic syndrome. Heterozygous mutations in the PAX2 gene on chromosome 10q24 can cause FSGS7. Here, we generated an induced pluripotent stem cell line SDQLCHi062-A from a thirteen -years-old boy with FSGS7 caused by heterozygous mutation (c.226 G>A, p.G76S) in the PAX2 gene (OMIM * 167409). The established iPSC line was validated by pluripotency markers expression, original gene mutation and demonstrated trilineage differentiation potential in vitro.

Establishment of an induced pluripotent stem cell (iPSC) line SDQLCHi045-A from peripheral blood mononuclear cells of a patient with Coffin-Siris syndrome 1 carrying a mutation in ARID1B gene.

Coffin-Siris syndrome 1 (CSS1) is a multiple malformation syndrome characterized by mental retardation associated with coarse facial features, hypertrichosis, sparse scalp hair, and hypoplastic or absent fifth fingernails or toenails. Mutations in the ARID1B gene are the most common cause of CSS1. Here, we generated an induced pluripotent stem cell line SDQLCHi045-A from a one-year-old girl with CSS1 caused by heterozygous mutation (c.1924C>T, p.Q642X) in the ARID1B gene (OMIM*135900). The established iPSC line was validated by pluripotency markers, original gene mutation and demonstrated trilineage differentiation potential in vitro.

Generation of a transgene-free iPS cell line (SDQLCHi053-A) from a young girl carrying a heterozygous mutation (c.427C > T) in SYNGAP1 gene.

The pathogenic mutations of Synaptic Ras GTPase-activating protein 1 (SYNGAP1) gene (OMIM #603384) have been tightly associated with a neurodevelopmental disease, also called autosomal dominant mental retardation type 5 (MRD5, OMIM #612621). We generated a human iPS cell line from a 34-month-old young girl bearing a recurrent heterozygous mutation (c.427C > T) of SYNGAP1. This cell line has great performance in pluripotency and shows differentiation potential towards three germ layers in vitro.

DCX variants in two unrelated Chinese families with subcortical band heterotopia: Two case reports and review of literature.

Introduction: Subcortical band heterotopia (SBH) is a rare brain developmental malformation caused by deficient neuronal migration during embryogenesis. Published literature on pediatric SBH cases caused by DCX mutations is limited. Methods: The detailed clinical and genetic features of two pediatric SBH with DCX mutations were analyzed. The available literature on DCX mutations was reviewed. Results: Both patients were girls with varying degrees of developmental delay. Patient 1 was short in stature with peculiar facial features. Patient 2 had an early seizure onset and developed drug-resistant epilepsy. Whole-exome sequencing (WES) revealed two de novo heterozygous variants of DCX (NM_178153.3), including a novel missense variant of c.568A > G (p.K190E) in P1 and a reported nonsense variant of c.814C > T (p.R272*) in P2. We reviewed all the available literature regarding DCX mutations. A total of 153 different mutations have been reported, with the majority of 99 (64.7 %) being missense mutations. Conclusion: Our study expanded the mutational spectrum of DCX, which has important implications for the study of genotype-phenotype correlations. Furthermore, it provided insights to better understand SBH and genetic counseling.

Clinical and genetic features of luscan-lumish syndrome associated with a novel de novo variant of SETD2 gene: Case report and literature review.

Introduction: Luscan-Lumish syndrome (LLS) is currently recognized as a rarely-observed condition featured with overgrowth, macrocephaly, obesity, type I Chiari malformation, and linguistic retardation. So far, there have been only a few LLS cases registered worldwide, but with none of them reported from China. To acquire a deeper understanding on the clinical and genetic features of this disease, a Chinese boy with LLS caused by a heterozygous variant in SETD2 gene was investigated in the present study. Methods: The patient was clinically examined and the medical history of his family was collected. Genetic testing was performed to determine the genetic etiology. Results: The proband was a boy aged 5-year-7-month-old, who was referred to our hospital due to "being a slow learner in kindergarten". The child had a history of delayed motor and language development in comparison to his peers. After admission, physical examination revealed tall stature and macrocephaly as the major manifestation, in addition to a relatively lower rating in intelligence assessment as well as abnormal MRI images showing a slightly shorter corpus callosum accompanied by a mildly thinner corpus callosum body. Whole exome sequencing (WES) revealed a heterozygous c.2514_2516delTAG (p.Ser838del) variant in SETD2 gene, which was subsequently identified as a novel de novo variant. According to the standardized genetic variant classification published by the American College of Medical Genetics and Genomics (ACMG), the variant, with a pathogenicity analysis result indicating PS2 + PM2_Supporting + PM4, was determined to be likely pathogenic. Through literature review, the clinical phenotypes of the 15 LLS cases were summarized, including 8 cases of overgrowth (53%), 13 cases of macrocephaly (87%), 11 cases of developmental delay (73%), 8 cases of autism (53%), and 7 cases of special facial features (47%). Besides, abnormal craniocerebral MRI findings were noticed in 7 cases. Despite that the mutation sites of the 15 patients varied from case to case, they showed a uniformly distributed pattern throughout the whole SETD2 gene, including 5 missense mutations, 5 frameshift mutations and 5 non-sense mutations. Conclusion: LLS, not having been recognized till recent years, is identified as an autosomal dominant syndrome triggered by SETD2 gene mutation. As the first report of LLS in China, the case in our study was proved to be associated with a unique type of SETD2 gene mutation that has never been reported previously, which is believed to enrich the mutation spectrum of SETD2 gene and also, deepening the clinicians' understanding on the disease.

Generation of an induced pluripotent stem cell line (SDQLCHi044-A) from a patient with autosomal dominant mental retardation type 5 harboring heterozygous mutation in SYNGAP1 gene.

Autosomal dominant mental retardation type 5 (MRD5) is a rare neurodevelopmental disorder caused by mutations in the SYNGAP1 gene. Here, we established an induced pluripotent stem cell (iPSC) line from peripheral blood mononuclear cells (PBMCs) of a 30-month-old boy carrying a heterozygous mutation (c.2059C > T) in the SYNGAP1 gene. The iPSCs exhibited a normal karyotype, expressed pluripotency markers, and displayed differentiation potential in vitro.

Diagnostic application of exome sequencing in Chinese children with suspected inherited kidney diseases.

Background: Inherited kidney diseases (IKDs) are a group of kidney diseases characterized by abnormal kidney structure or function caused by genetic factors, but they are not easily diagnosed in childhood due to either nonspecific symptoms and signs or clinically silent symptoms in the early stages until the progressive stages, even end-stages. Early diagnosis of IKDs is very urgent for timely treatment and improving outcomes of patients. So far, the etiological diagnosis has been accelerated with the advance of clinical genetic technology, particularly the advent of next-generation sequencing (NGS) that is not only a powerful tool for prompt and accurate diagnosis of IKDs but also gives therapy guidance to decrease the risk of unnecessary and harmful interventions. Methods: The patients presenting with urinalysis abnormalities or structural abnormalities from 149 Chinese families were enrolled in this study. The clinical features of the patients were collected, and the potentially causative gene variants were detected using exome sequencing. The clinical diagnostic utility of the genetic testing was assessed after more detailed clinical data were analyzed. Result: In total, 55 patients identified having causative variants by exome sequencing were genetically diagnosed, encompassing 16 (29.1%) autosomal dominant IKDs, 16 (29.1%) autosomal recessive IKDs, and 23 (41.8%) X-linked IKDs, with 25 unreported and 45 reported variants. The diagnostic yield was 36.9%. The utility of the exome sequencing was accessed, 12 patients (21.8%) were confirmed to have suspected IKDs, 26 patients (47.3%) discerned the specific sub-types of clinical category, and 17 patients (30.9%) with unknown etiology or lack of typical manifestations were reclassified. Conclusion: Our study supported that genetic testing plays a crucial role in the early diagnosis for children with IKDs, which affected follow-up treatment and prognostic assessment in clinical practice. Moreover, the variant spectrum associated with IKDs was expanded.

Phenotype and genotype analyses of Chinese patients with autosomal dominant mental retardation type 5 caused by SYNGAP1 gene mutations.

Background: Autosomal dominant mental retardation type 5 (MRD5), a rare neurodevelopmental disorder (NDD) characterized by intellectual disability (ID), developmental delay (DD), and epilepsy predominantly, is caused by a heterozygous mutation in the SYNGAP1 gene. SYNGAP1 mutations have been rarely reported in the Chinese population. Here, we present an investigation of SYNGAP1 mutations in a clinical cohort with ID and DD in Shandong, a northern province in China, to further explore the genotype and phenotype correlations. Methods: A retrospective study was conducted on 10 children with SYNGAP1 mutations presenting ID, DD, and epilepsy who were diagnosed between January 2014 and May 2022. Clinical data and genetic tests were collected. Treatment and regular follow-ups were carried out to pay close attention to the prognosis of the patients. Results: We described 10 unrelated affected individuals with SYNGAP1 mutations, displaying ID, DD, epilepsy, or seizures. All mutations of SYNGAP1 in the 10 patients were de novo, except patient 3 whose father was unavailable, including five nonsense mutations, two frameshift mutations, two splicing mutations, and one codon deletion. Among these mutations, five were novel and the other five were previously reported. Significantly, all patients with epilepsy were sensitive to anti-seizure drugs, especially sodium valproate. Furthermore, rehabilitation training seemed to exert a more improved effect on motor development than language development for the patients. Conclusion The 10 patients carrying SYNGAP1 mutations were diagnosed as MRD5. Five novel genetic mutations were found, which expanded the mutational spectrum of the SYNGAP1 gene. The identification of these mutations in this study helps explore the relationship between genotypes and phenotypes and contributes to genetic counseling and therapeutic intervention for patients with MRD5.

Genotypic and phenotypic characteristics of 12 chinese children with glycogen storage diseases.

Background: Glycogen storage diseases (GSDs) are known as a group of disorders characterized by genetic errors leading to accumulation of glycogen in various tissues. Since different types of GSD can sometimes be clinically indistinguishable, next generation sequencing is becoming a powerful tool for clinical diagnosis. Methods: 12 patients with suspected GSDs and their parents were enrolled in this study. The clinical and laboratory data of the patients were reviewed. Causative gene variants were identified in the patients using whole exome sequencing (WES) and verified by Sanger sequencing. Results: Genetic testing and analysis showed that 7 patients were diagnosed with GSD II (Pompe disease), 2 patients with GSD III, 1 patient with GSD VI, and 2 patients with GSD IXα. A total number of 18 variants were identified in 12 patients including 11 variants in GAA gene, 3 variants in AGL gene, 2 variants in PYGL gene and 2 variants in PHKA2 gene, of which 9 variants were reported and 9 variants were novel. SIFT, Polyphen-2, Mutation Taster, and REVEL predicted the novel variants (except GAA c.1052_1075 + 47del) to be disease-causing. The 3D structures of wild/mutant type GAA protein were predicted indicating that variants p. Trp621Gly, p. Pro541Leu, p. Ser800Ile and p. Gly293Trp might affect the proteins function via destroying hydrogen bonds or conformational constraints. Neither liver size nor laboratory findings allow for a differentiation among GSD III, GSD VI and GSD IXα. Conclusion: Our study expanded the variation spectrum of genes associated with GSDs. WES, in combination with clinical, biochemical, and pathological hallmarks, could provide accurate results for diagnosing and sub-typing GSD and related diseases in clinical setting.