OBJECTIVE: To explore the clinical and genetic features of a child with Pontocerebellar hypoplasia type 2B (PCH2B) due to compound heterozygous variants of the TSEN2 gene. METHODS: A PCH2B patient presented at Department of Pediatric Neurology, Xiangya Hospital of Central South University in June 2023 was selected as the study subject. Clinical data of the patient were retrospectively analyzed. The patient and her parents were subjected to whole exome sequencing and bioinformatic analysis. Pathogenicity of the candidate variants were classified based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). A literature review was also conducted by searching the China National Knowledge Infrastructure (CNKI), Wanfang Data, and PubMed databases from their establishment to May 2025 using keywords "TSEN2 gene" "PCH2B" and "Pontocerebellar Hypoplasia 2B" to summarize the clinical and genotypic features of patients with PCH2B due to variants of the TSEN2 gene. This study was approved by the Medical Ethics Committee of the Hospital (No.: #202310892). RESULTS: The patient, a 6-year-5-month-old girl, had exhibited severe global developmental delay, developmental regression, autism spectrum disorder, myoclonus of eyelids, feeding difficulty, irritability, progressive microcephaly, esotropia, and hypotonia. MRI showed reduced volume of bilateral cerebellar hemispheres and vermis. Genetic testing revealed that she has harbored compound heterozygous variants of the TSEN2 gene (NM_025265.4), namely c.1054A>T (p.Lys352*) and c.899G>T (p.Ser300Ile), which were inherited from her father and mother, respectively. Both variants were classified as likely pathogenic based on the ACMG guidelines and were previously unreported. Literature review has identified six PCH2B patients with missense, nonsense, frameshift, and splice site variants of the TSEN2 gene. Their main clinical manifestations included global developmental delay, progressive microcephaly, feeding difficulties, irritability, and vermis hypoplasia. Cranial MRI and genetic testing are crucial for definite diagnosis. CONCLUSION The c.1054A>T (p.Lys352*) and c.899G>T (p.Ser300Ile) compound heterozygous variants of the TSEN2 gene probably underlay the pathogenesis in this patient. Above findings has expanded the genotypic and phenotypic spectra of TSEN2-related PCH2B, and offered guidance for genetic counseling for this family.
Child ; Female ; Humans ; Cerebellar Diseases/genetics* ; Exome Sequencing ; Heterozygote ; Mutation

OBJECTIVE: To explore the genetic etiology of Pontocerebellar Hypoplasia Type 2D (PCH2D) due to compound heterozygous variants of the SEPSECS gene and to conduct a literature review. METHODS: A child with PCH2D diagnosed at the Children's Hospital of Nanjing Medical University due to "motor and cognitive retardation" in June 2022 was selected as the study subject. Clinical and imaging data were collected. Genomic DNA was extracted from the peripheral blood samples of the child and her parents. Whole-exome sequencing (WES) was conducted using capture-based high-throughput sequencing technology. Candidate variants were confirmed by Sanger sequencing and bioinformatics analysis. The pathogenicity of variant was rated according to the Standards and Guidelines for the Interpretation of Sequence Variants released by American College of Medical Genetics and Genomics (ACMG). Additionally, relevant literature on PCH2D caused by SEPSECS gene variants was reviewed to assess the genotype-phenotype correlation. This study was approved by the Medical Ethics Committee of the hospital (Ethical No.: 202402022-1). RESULTS: The child, a 1-year-and-3-month-old girl, had presented with global developmental delay, progressive microcephaly, hypotonia, elevated blood lactic acid, feeding difficulties, and absent tendon reflexes. Cranial MRI indicated thinning of the splenium of the corpus callosum. Electromyography suggested peripheral neurogenic changes primarily affecting sensory nerves. WES revealed the she has harbored compound heterozygous variants of the SEPSECS gene, namely c.194A>G (p.N65S) and c.896_c.897insA (p.N299fs*2) (NM_016955), which were inherited from her father and mother, respectively. Neither of her parents had related clinical manifestations. According to the ACMG guidelines, the c.194A>G (p.N65S) variant was classified as pathogenic (PM1+PM2_Supporting+PM3+PP3), and the c.896_c.897insA (p.N299fs*2) variant was as likely pathogenic (PVS1+PM2_Supporting). A total of 18 relevant literature were retrieved, which have involved 32 patients (including this case). The p.N65S variant has been reported previously, while the p.N299fs*2 variant is novel. CONCLUSION Compound heterozygous variants in the SEPSECS gene probably underlay the pathogenesis of PCH2D in this child. Above finding has expanded the mutational and phenotypic spectrum of the SEPSECS gene.
Humans ; Female ; Infant ; Heterozygote ; Cerebellar Diseases/genetics* ; Membrane Proteins/genetics* ; Exome Sequencing ; Mutation

OBJECTIVE: To analyze the clinical characteristics and genotypic changes of six children with RARS2 gene variants. METHODS: The clinical data of 6 children with RARS2 gene variants diagnosed at the Third Affiliated Hospital of Zhengzhou University from January 2017 to August 2024 were collected. Genetic variants were detected using trio-whole exome sequencing. Genomic DNA was extracted from samples and subjected to high-throughput sequencing. Variants were detected and analyzed using relevant databases and software. Pathogenic variants were validated by Sanger sequencing. The protein structure encoded by a previously unreported variant was predicted using a SWISS-MODEL online server. This study was approved by the Medical Ethics Committee of the Third Affiliated Hospital of Zhengzhou University (Ethics No.: 2024-373-01). RESULTS: Among the six children, four were males and two were females, with the most recent follow-up age ranging from 1-year-and-1-month to 7 years old. The age of onset was under 1 year in all cases. All six children exhibited seizures, including infantile spasms in three, spasms and tonic spasms in one, and focal seizures in two. One child became seizure-free for 4 ~ 5 years following Valproic acid combined with topiramate and adrenocorticotropic hormone (ACTH) pulse therapy, but subsequently experienced a relapse. Another child has remained seizure-free for nearly one year with oral sodium valproate, levetiracetam, and a "cocktail" therapy. Seizures were not controlled in the remaining four children. Pontocerebellar hypoplasia was observed on neuroimaging in two children. All six patients exhibited severe psychomotor retardation. A total of 10 RARS2 gene variants were identified, three of which were previously unreported. CONCLUSION The predominant clinical features of Pontocerebellar hypoplasia associated with RARS2 gene variants include infantile onset, severe psychomotor retardation or regression, drug-resistant epilepsy, and feeding difficulties. The characteristic neuroimaging finding is pontocerebellar hypoplasia. However, its appearance may vary widely with time. The majority of affected children have a poor prognosis.
Humans ; Male ; Female ; Child, Preschool ; Infant ; Child ; Olivopontocerebellar Atrophies/genetics* ; Arginine-tRNA Ligase/genetics* ; Mutation ; Cerebellar Diseases

OBJECTIVETo confirm the genetic diagnosis for providing services for genetic counseling and prenatal diagnosis, we analyzed the clinical and genetic data of a pedigree which is clinically diagnosed as Joubert syndrome.

METHODA Joubert syndrome pedigree was enrolled as subject of this study from our hospital's outpatients in 2013. Following the medical history collection of the proband and the suffering fetus, target sequence capture and the next-generation sequencing technology were used for the proband and the suffering fetus to find the causative genes and sanger sequencing for the members of the pedigree to check and verify if the inherited mutations are in accordance with the Mendelian inheritance. Combining the clinical symptoms and signs with the total testing results, we analyzed the Joubert syndrome pedigree clinically and genetically.

RESULTThe proband showed abnormal respiratory patterns (neonatal tachypnea) and hypertonia without abnormal eye movements, and reflected the molar tooth sign on the magnetic resonance imaging. And afterwards the patient developed hypotonia, ataxia, growth and intellectual disability accompanied by congenital blepharoptosis. There were no any symptoms and signs of liver, kidney and eyesight abnormalities so far. The affected fetus showed hydrocephalus by the auxiliary examination during the second trimesters of pregnancy without any appearance deformities. Both the proband and the affected fetus carried a missense mutation of CC2D2A gene c.2999A > T (p.Glu1000Val) from their father and carried the deletion of exon 20-21 on the same gene. Both variations were confirmed to be the Mendelian genetic compound heterozygous pattern. Whereas, the missense mutations c.2999A > T (p.Glu1000Val) on the CC2D2A gene have been proved to be inherited from the proband's father and the proband as well as the affected fetus. However, the proband's mother was normal at this locus of CC2D2A gene. The missense mutations c.2999A >T (p.Glu1000Val) have been confirmed to accord with Mendelian inheritance.

CONCLUSIONThe Joubert syndrome patient may show hypertonia in the early postnatal days as a result of hydrocephalus during the second and third trimesters of pregnancy besides manifesting hypotonia, ataxia, growth and intellectual disability markedly with age accompanied by the congenital blepharoptosis and revealing the molar tooth sign on the magnetic resonance imaging, considering the medical history and the whole testing results, the compound heterozygous mutations of c.2999A > T (p.Glu1000Val) and deletion of exon 20-21 of CC2D2A gene in the pedigree may be the causal gene mutations.

Abnormalities, Multiple ; genetics ; Cerebellar Diseases ; Cerebellum ; abnormalities ; Exons ; Eye Abnormalities ; genetics ; Female ; Genetic Testing ; Heterozygote ; Humans ; Hydrocephalus ; Kidney Diseases, Cystic ; genetics ; Male ; Mutation ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Proteins ; genetics ; Retina ; abnormalities

X-linked adrenoleukodystrophy (X-ALD) shows a wide range of phenotypic expression, but clinical presentation as an isolated lesion of the cerebellar white matter and dentate nuclei has not been reported. We report an unusual presentation of X-ALD only with an isolated lesion of the cerebellar white matter and dentate nuclei. The proband, a 37-year-old man presented with bladder incontinence, slurred speech, dysmetria in all limbs, difficulties in balancing, and gait ataxia. Brain magnetic resonance imaging showed an isolated signal change of white matter around the dentate nucleus in cerebellum. With high level of very long chain fatty acid, gene study showed a de novo mutation in exon 1 at nucleotide position c.277_296dup20 (p.Ala100Cysfs*10) of the adenosine triphosphate-binding cassette D1 gene. It is advised to consider X-ALD as a differential diagnosis in patients with isolated cerebellar degeneration symptoms.
ATP-Binding Cassette Transporters/*genetics ; Adrenoleukodystrophy/blood/*genetics ; Adult ; Cerebellar Diseases/blood/*genetics ; Fatty Acids/blood ; Humans ; Male ; Mutation

One of the most widespread cellular organelles in nature is cilium, which is found in many unicellular and multicellular organisms. Formerly thought to be a mostly vestigial organelle, the cilium has been discovered in the past several decades to play critical motile and sensory roles involved in normal organogenesis during development. The role of cilia has also been implicated in an ever increasing array of seemingly unrelated human diseases, including blindness, kidney cysts, neural tube defects and obesity. In this article we review some of the recent developments in research on cilia, and how defects in ciliogenesis and function can give rise to developmental disorders and disease.
Abnormalities, Multiple ; pathology ; Animals ; Cerebellar Diseases ; genetics ; pathology ; Cilia ; physiology ; ultrastructure ; Flagella ; physiology ; Hedgehog Proteins ; metabolism ; Humans ; Models, Animal ; Polycystic Kidney Diseases ; pathology ; Protein Transport ; Signal Transduction ; Wnt Proteins ; metabolism