OBJECTIVE: To investigate the clinical characteristics and genetic etiology of a child with Cortical dysplasia, complex, with other brain malformations 4 (CDCBM4) and epilepsy due to a TUBG1 gene variant. METHODS: A child diagnosed with CDCBM4 and epilepsy at the Children's Medical Center of the Affiliated Hospital of Guangdong Medical University in May 2024 was selected as the study subject. Clinical data were retrospectively analyzed. Peripheral venous blood samples were collected from the child and her parents for genomic DNA extraction. Trio-based whole-exome sequencing (WES) was performed, and candidate variants were validated by Sanger sequencing. According to the Standards and Guidelines for the Interpretation of Sequence Variants established by the American College of Medical Genetics and Genomics (ACMG), candidate variants were classified for pathogenicity. This study was approved by the Medical Ethics Committee of the Affiliated Hospital of Guangdong Medical University (Ethics No.: PJ2021-097). RESULTS: The child, a 4-month-old female infant, had no special facial features, normal limb muscle strength, and increased muscle tone of infantile onset, with generalized tonic-clonic seizures as the main manifestation. During seizures, she exhibited head retroflexion, tightly closed eyes, and tonic convulsions of the limbs, occurring approximately 2-3 times per day. Electroencephalogram suggested bilateral anterior predominant medium-to-high amplitude 7-8 Hz mixed rhythm discharges. Head MRI revealed ventricular system dilatation and pachygyria. Trio-WES results indicated that the child has harbored a TUBG1 gene variant of c.776C>T (p.Ser259Leu). Sanger sequencing verification showed that neither of her parents had carried the same variant, confirming it as de novo in origin. According to the ACMG guidelines, the variant was rated as pathogenic (PS2+PS3+PM2_Supporting+PP3). Combining the child's clinical phenotype, the child was diagnosed as CDCBM4 with epilepsy. CONCLUSION Children with CDCBM4 and epilepsy due to TUBG1 gene variants may show pachygyria or agyria and commonly present with intellectual and motor developmental delays and seizure disorders of variable severity. The heterozygous TUBG1 c.776C>T (p.Ser259Leu) variant is likely the genetic etiology underlying this disorder. The results of this study has expanded the mutational spectrum of the TUBG1 gene associated with CDCBM4 and epilepsy.
Humans ; Female ; Epilepsy/genetics* ; Malformations of Cortical Development/genetics* ; Infant ; Phenotype ; Exome Sequencing ; Microtubule-Associated Proteins/genetics*

OBJECTIVE: To explore the genetic basis for a child with multiple malformations. METHODS: A child who had presented at Shanxi Provincial Children's Hospital in February 2021 was selected as the study subject. Clinical data of the patient was collected, and whole exome sequencing (WES) was carried out to screen pathogenic variants associated with the phenotype. Candidate variant was validated by Sanger sequencing of her family members. RESULTS: The child had normal skin, but right ear defect, hemivertebral deformity, ventricular septal defect, arterial duct and patent foramen ovale, and separation of collecting system of the left kidney. Cranial MRI showed irregular enlargement of bilateral ventricles and widening of the distance between the cerebral cortex and temporal meninges. Genetic testing revealed that she has harbored a heterozygous variant of NM_178014.4: c.217A>G (p.Met73Val) in the TUBB gene, which was unreported previously and predicted to be likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). The child was diagnosed with Complex cortical dysplasia with other brain malformations 6 (CDCBM6). CONCLUSION CDCBM is a rare and serious disease with great genetic heterogeneity, and CDCBM6 caused by mutations of the TUBB gene is even rarer. Above finding has enriched the variant and phenotypic spectrum of the TUBB gene, and provided important reference for summarizing the genotype-phenotype correlation of the CDCBM6.
Humans ; Child ; Female ; Abnormalities, Multiple ; Blood Group Antigens ; Family ; Malformations of Cortical Development/genetics* ; Brain ; Mutation

OBJECTIVE: To explore the genetic basis for a fetus with dysgenesis of corpus callosum and other brain malformations. METHODS: Whole exome sequencing was carried out for the fetus and its parents. Suspected pathogenic variants were verified by Sanger sequencing. RESULTS: A novel de novo missense variant c.758T>A (p.L253Q) of the TUBB2B gene was identified, which was unreported previously. Based on the guidelines from the American College of Medical Genetics, the c.758T>A variant was predicted to be likely pathogenic. Bioinformatics analysis predicted that the leucine at position 253 was highly conserved among various species, and the c.758T>A variant may impact the formation of hydrogen bonds between Leu253 and Asp249 and Met257 residues, which in turn may affect the combination of GTP/GDP and function of the TUBB2B protein. CONCLUSION The c.758T>A variant of the TUBB2B gene probably underlay the fetal malformations in this Chinese family. Above discovery has enriched the spectrum of TUBB2B gene variants and provided a basis for genetic counseling and prenatal diagnosis.
Brain ; Female ; Fetus/abnormalities* ; Humans ; Malformations of Cortical Development/genetics* ; Pregnancy ; Prenatal Diagnosis ; Tubulin/genetics* ; Whole Exome Sequencing

OBJECTIVE: To explore the genetic basis for a child featuring complex cortical dysplasia and other brain malformations (CDCBM3). METHODS: Genomic DNA was extracted from peripheral blood samples from the patient and his parents. Whole exome sequencing (WES) was carried out for the family trio. Suspected variant was verified by Sanger sequencing. RESULTS: The proband, a 1-year-and-2-month old Chinese boy, had presented with motor developmental delay, lissencephaly, severe cognitive impairments, absent speech and congenital laryngomalacia. WES revealed that he has harbored a heterozygous missense variant of the KIF2A gene, namely NM_001098511.2: c.952G>A, p.Gly318Arg (GRCh37/hg19). The highly conserved residue is located around the ATP nucleotide-binding pocket in the kinesin motor domain (PM1). The variant was not found in the Genome Aggregation Database and the 1000 Genomes Project (PM2), and was predicted to be deleterious on the gene product by multiple in silico prediction tools (PP3). This variant was unreported previously and was de novo in origin (PS2). Based on the ACMG guidelines, it was categorized as likely pathogenic (PS2+PM1+PM2+PP3). Furthermore, the congenital laryngomalacia found in our patient was absent in previously reported CDCBM3 cases. CONCLUSION The novel variant of the KIF2A gene probably underlay the disorders in the proband. Above finding has expanded the phenotypic and mutational spectrum of CDCBM3.
Asians/genetics* ; Brain ; China ; Humans ; Infant ; Kinesins/genetics* ; Male ; Malformations of Cortical Development/genetics* ; Whole Exome Sequencing

OBJECTIVETo study the expression of P-glycoprotein, multi-drug resistance associated protein and major vault protein in pathologic brain specimens, and to investigate their roles in the pathogenesis of refractory epilepsy.

METHODSImmunohistochemical study was performed in pathology specimens from 18 cases of refractory epilepsy (including 5 cases of focal cortical dysplasia, 3 cases of tuberous sclerosis, 5 cases of ganglioglioma and 5 cases of dysembryoplastic neuroepithelial tumor).

RESULTSBoth the P-glycoprotein and major vault protein were localized in microvascular endothelium of the lesions. Major vault protein was also seen in balloon cells and some neuronal cells. On the other hand, multi-drug resistance associated protein was mainly localized in the neuronal component of the lesions. In general, the expression of P-glycoprotein and major vault protein in tumoral tissue was higher than that in non-tumoral tissue. The expression of multi-drug resistance associated protein and major vault protein was also different in the neoplastic glial cells of ganglioglioma and dysembryoplastic neuroepithelial tumor.

CONCLUSIONSP-glycoprotein, multi-drug resistance associated protein and major vault protein contribute to the pathogenesis of refractory epilepsy. They may however have different roles, with different cellular localization.

ATP-Binding Cassette, Sub-Family B, Member 1 ; analysis ; Adolescent ; Adult ; Brain ; metabolism ; Brain Neoplasms ; chemistry ; Child ; Drug Resistance, Multiple ; Epilepsy ; drug therapy ; genetics ; metabolism ; Female ; Ganglioglioma ; genetics ; metabolism ; Humans ; Male ; Malformations of Cortical Development ; genetics ; metabolism ; Multidrug Resistance-Associated Proteins ; genetics ; metabolism ; pharmacology ; Tuberous Sclerosis ; metabolism ; Young Adult

OBJECTIVETo evaluate the alteration of subunits composition in NMDA receptor and the alterations of the expression and distribution of NMDA receptors and parvalbumin (PV)-positive neurons in focal cortical dysplasia (FCD) cortices.

METHODSTwenty cases of FCD samples (including all four subtypes of FCD) obtained during epilepsy surgery and 4 controls were analysed by immunohistochemical staining for NR1, NR2A/B and PV.

RESULTSIncreased expression of NR1 was detected in the giant neurons and dysmorphic neurons in FCD; while pronounced expression of NR2A/B was detected in immature neurons, giant neurons and dysmorphic neurons of FCD, especially in somata and processes of the immature neurons. Compared with the controls, FCD cortices showed prominent scattered arrangement of PV positive neurons and fibers, dramatically decreased number of PV positive interneurons and PV background staining, especially in foci of FCD II subtype.

CONCLUSIONThere are increased expressions of NR1 and NR2A/B subunits in FCD abnormal neurons, as well as scattered and reduced expressions of PV positive neurons and fibers in FCD cortices.

Adolescent ; Biomarkers, Tumor ; metabolism ; Cerebral Cortex ; metabolism ; pathology ; Child ; Child, Preschool ; Epilepsies, Partial ; pathology ; Female ; Gene Expression Regulation ; Humans ; Infant ; Interneurons ; metabolism ; Male ; Malformations of Cortical Development ; pathology ; Neurons ; metabolism ; Parvalbumins ; analysis ; isolation & purification ; Receptors, N-Methyl-D-Aspartate ; genetics ; metabolism