BACKGROUND

Spinocerebellar Ataxia (SCA) represents a rare and heterogeneous group of neurodegenerative disorders, typically characterized by the progressive loss of coordination of movement, resulting primarily from cerebellar dysfunction. This case report discusses the history, clinical presentation, and diagnostic findings of a patient who exhibited symptoms suggestive of SCA. Given the notable familial pattern, further evaluation was undertaken using genetic testing. The objective of this paper is to present the clinical, genetic findings, and inheritance pattern of a patient and her family with SCA.

Our case is a 36-year-old Filipino female with progressive cerebellar dysfunction for over a decade. Cranial Magnetic Resonance Imaging (MRI) revealed bilateral cerebellar atrophy. Genetic testing identified a Variant of Uncertain Significance (VUS) in the inositol 1,4,5- triphosphate receptor type 1 (ITPR1) gene, a finding consistent with Spinocerebellar Ataxia type 15 (SCA 15). This represents the first reported case of SCA 15 in the Philippines and in Asia.

A detailed pedigree assessment revealed that 18 immediate and extended family members had similar symptoms suggestive of hereditary ataxia. Ten relatives had already passed away, and four could not be contacted for further evaluation. Three available family members were examined and likewise demonstrated comparable cerebellar findings, supporting a familial pattern of the disease.

The findings from this case series suggest that SCA 15 may be present in Filipino families, with an autosomal dominant (AD) inheritance pattern. While no data on the prevalence or incidence of SCA15 in the Philippines currently exists, this report calls attention to the need for further research and genetic studies within the Filipino population.

Dentatorubral-pallidoluysian atrophy（DRPLA） is a rare autosomal dominant neurodegenerative disease caused by CAG triplet expansion in the atrophin 1 （ATN1） gene. Up to now， the pathogenesis of DRPLA remains unclear. The main clinical features of DRPLA include myoclonus， epilepsy， ataxia， choreoathetosis， and cognitive impairment. DRPLA has great clinical heterogeneity， and the number of CAG repeats is negatively correlated with age of onset and disease severity. Some patients with late-onset DRPLA may have atypical manifestations without typical imaging changes， which brings challenges to the diagnosis of the disease. This article reviews the pathogenesis， pathological features， clinical and imaging manifestations， diagnosis， and potential treatment of DRPLA， in order to deepen the understanding of this disease.
Ataxia ; Myoclonus

Familial hemophagocytic lymphohistiocytosis （FHL） with central nervous system involvement as the initial clinical manifestation is very rare and has atypical clinical manifestations， which often leads to difficulties in early diagnosis and misdiagnosis. This article reports two cases of FHL confirmed by genetic testing in Department of Neurology， Women and Children’s Hospital of Qingdao University. One patient was a boy with 1‒3 years of age， while the other patient was a girl of pre-school age； both patients had the main clinical manifestations of unstable walking and dysarthria. Brain MRI findings of the boy suggested multiple abnormal signals in the bilateral hemispheres and the cerebellum， and brain MRI findings of the girl suggested multiple symmetrical hyperintensities in the bilateral frontal lobes， the periventricular region， and the basal ganglia. Both children were found to have PRF1 gene mutations. This article reviews relevant literature to improve the understanding of this disease among clinicians， and the possibility of this disease should be considered in case of unexplained central nervous system involvement. For suspected cases， it is recommended to conduct comprehensive examinations and genetic testing， so as to achieve early diagnosis， start treatment in a timely manner， and improve prognosis.
Ataxia

Objective To investigate the role of specific imaging parameters in the clinical diagnosis and differential diagnosis of multiple system atrophy with predominant cerebellar ataxia （MSA-C）. Methods Imaging data including pontine volume were measured for 34 patients with MSA-C who were admitted to Department of Neurology， Shaanxi Provincial People’s Hospital， from January 2021 to October 2024， and these patients were compared with 9 patients with progressive supranuclear palsy （PSP）， 8 patients with spinocerebellar ataxia （SCA）， and 32 normal controls. Results There was a significant difference in pontine volume between the MSA-C group and the PSP group， as well as between the MSA-C group and the normal control group （P<0.008 3）， while there was no significant difference between the MSA-C group and the SCA group （P>0.008 3）. There was no significant difference in pontine volume between the PSP group and the SCA group and between the PSP group and the normal control group （P>0.008 3）， and there was a significant difference in pontine volume between the SCA group and the normal control group （P<0.008 3）. The receiver operating characteristic （ROC） curve analysis showed that pontine volume had a cut-off value of 8.66 cm3 in the diagnosis of MSA-C， with an area under the ROC curve （AUC） of 0.972， a sensitivity of 94.12%， and a specificity of 100%； pontine volume had a cut-off value of 8.66 cm3 in the differential diagnosis of MSA-C from PSP， with an AUC of 0.961， a sensitivity of 94.1%， and a specificity of 100%； pontine volume had a cut-off value of 6.79 cm3 in the differential diagnosis of MSA-C from SCA， with an AUC of 0.783， a sensitivity of 52.94%， and a specificity of 100%. Conclusion As the most objective indicator for evaluating pontine atrophy， pontine volume has a great significance in the diagnosis and differential diagnosis of MSA-C.
Ataxia

OBJECTIVE: To explore the clinical manifestations and genetic characteristics of a child with Leukoencephalopathy with ataxia (LKPAT) caused by a CLCN2 gene variant. METHODS: A retrospective analysis was conducted on the clinical data of a child admitted to Hunan Children's Hospital in June 2024 due to "intermittent convulsions for 13 days". Peripheral blood samples were collected from the child and his parents for whole exome sequencing, followed by Sanger sequencing validation and pathogenicity analysis of candidate variants. Literature searches were performed using the keywords "CLCN2 gene" "chloride channel-2" "leukoencephalopathy with ataxia/LKPAT" "leukoencephalopathy" in both Chinese and English on CNKI, Wanfang, and PubMed databases. The search time was set from the establishment of the databases to July 31, 2024. Childhood-onset LKPAT literature was screened and analyzed. This study was approved by the Medical Ethics Committee of Hunan Children's Hospital (Ethics No. HCHLL-2024-351). RESULTS: The child was a 7-month-and-26-day-old male infant born to consanguineous parents, presenting with epileptic seizures and borderline development. Cranial MRI revealed symmetrical long T₂ signal shadows in the posterior limb of the internal capsule, cerebral peduncle, pons, and middle peduncle of the cerebellum. Video electroencephalogram (EEG) showed an abnormal childhood EEG with one focal seizure. Whole exome sequencing revealed a homozygous c.2201dup (p.Glu735Ter) variant in the CLCN2 gene of the child. Sanger sequencing confirmed that the variant was inherited from both parents. According to the guidelines of the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP), this variant was classified as pathogenic (PVS1+PM3_Supporting+PM2_Supporting). A total of 8 relevant literature were retrieved, together with the present case, 16 childhood-onset LKPAT patients were cumulatively reported, which consisted of 9 males and 7 females. Twelve CLCN2 gene variants were involved, including 2 nonsense variants, 3 missense variants, 7 frameshifting variants, 2 c.61dup variants, and 5 c.1709G>A variants. The initial symptoms of the 16 patients included headache, ataxia, epileptic seizures, spasticity, developmental delay, lower back pain, hearing impairment, and intention tremor. Three patients had onset of the disease before the age of one, of which 2 had epileptic seizures as the initial symptom. CONCLUSION The homozygous variant CLCN2: c.2201dup (p.Glu735Ter) is considered the pathogenic cause of LKPAT in this child, marking the first childhood-onset case reported in China. Genetic testing has facilitated the diagnosis of childhood-onset LKPAT and expanded the spectrum of CLCN2 gene mutations.
Humans ; Chloride Channels/genetics* ; Male ; CLC-2 Chloride Channels ; Leukoencephalopathies/genetics* ; Infant ; Ataxia/genetics* ; Homozygote ; Mutation ; Retrospective Studies ; Exome Sequencing ; Genetic Testing ; Female

OBJECTIVE: To analyze the clinical characteristics and genetic etiology of a child with Christianson syndrome (CS). METHODS: A 1-year-and-5-month-old boy with CS diagnosed at the First Affiliated Hospital of Zhengzhou University in April 2021 was selected as the study subject. Clinical data were retrospectively analyzed. Peripheral blood samples were obtained from the child and his parents, followed by genomic DNA extraction and whole exome sequencing (WES). Candidate variant was validated by Sanger sequencing. This study has been approved by the Medical Ethics Committee of the Hospital of Zhengzhou University (Ethics No. 2024-KY-1103-001). RESULTS: The child has manifested with seizures, microcephaly, and global developmental delay. WES revealed that he has harbored a novel de novo hemizygous nonsense variant of the SLC9A6 gene, namely c.1014G>A (p.W338*). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic. CONCLUSION The hemizygous c.1014G>A nonsense variant of the SLC9A6 gene probably underlay the pathogenesis in this child. Above discovery has expanded mutational spectrum of the SLC9A6 gene and enabled definite diagnosis of the child.
Humans ; Male ; Infant ; Microcephaly/genetics* ; Spasms, Infantile/genetics* ; Sodium-Hydrogen Exchangers/genetics* ; Exome Sequencing ; Intellectual Disability/genetics* ; Genetic Diseases, X-Linked/genetics* ; Mutation ; Seizures/genetics* ; Ataxia ; Epilepsy ; Ocular Motility Disorders

OBJECTIVE: To explore the clinical characteristics and genetic cause of a child with gastrointestinal hemorrhage and Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) and to review the literature. METHODS: Clinical data of a child with gastrointestinal hemorrhage with CRMCC admitted to the Hepatology Department of Hunan Children's Hospital in September 2019 were collected, and peripheral blood DNA of the child and his parents were analyzed by whole exome sequencing. Candidate variants were validated by Sanger sequencing, followed by bioinformatics analysis, American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants pathogenicity classification, and protein structure prediction. A literature search with "Coats Plus syndrome" or "Cerebroretinal microangiopathy with calcifications and cysts" as keywords was conducted at PubMed, China National Knowledge Infrastructure and Wanfang databases to include recently published studies (up to December 2023). This study has been approved by the Ethics Committee of Hunan Children's Hospital (Ethics No. KY2020-07). Informed consent for clinical research was obtained from the guardian of the child. RESULTS: The proband was a 10-year-10-month-old boy. The clinical manifestations were intrauterine and postnatal growth retardation, gastrointestinal hemorrhage, liver fibrosis, panhemopenia, bilateral exudative retinopathy, intracranial lesions and facial pigmentation. WES and Sanger sequencing revealed two novel heterozygous variants in the CTC1 gene: c.787G>A (p.Val263Met) in exon 5 and c.2930C>G (p.Ser977Cys) in exon 17, which were inherited from his mother and father, respectively. According to ACMG pathogenicity classification, both missense variants were classified as variants of uncertain significance (VUS). Protein structure prediction showed the absence of LIG_SH3_3 motif and LIG_SH3_3 motif, and the p.Ser977Cys mutation may affect the binding between CST (CTC1-STN1-TEN) complex and DNA strand. The child had continued to experience recurrent gastrointestinal bleeding episodes despite propranolol treatment, but the condition was controlled after liver transplantation. According to the predefined literature search strategy of this study, a total of 10 relevant articles on pediatric CRMCC patients were retrieved, involving 11 children with gastrointestinal bleeding. Pharmacological and endoscopic therapies play a certain role in the management of CRMCC children complicated with gastrointestinal bleeding. CONCLUSION The CTC1 gene c.787G>A and c.2930C>G variants probably underlay CRMCC in this child. This study has broadened the variation spectrum of CTC1-related diseases and provided a basis for genetic counseling. Liver transplantation may be an important treatment for gastrointestinal hemorrhage in children who do not respond well to medication and endoscopic therapy.
Humans ; Male ; Gastrointestinal Hemorrhage/genetics* ; Child ; Calcinosis/genetics* ; Cysts/genetics* ; Central Nervous System Cysts/genetics* ; Mutation ; Exome Sequencing ; Leukoencephalopathies ; Retinal Diseases ; Seizures ; Muscle Spasticity ; Brain Neoplasms ; Ataxia

CAPOS syndrome is an autosomal dominant neurological disorder caused by mutations in the ATP1A3 gene. Initial symptoms, often fever-induced, include recurrent acute ataxic encephalopathy in childhood, featuring cerebellar ataxia, optic atrophy, areflflexia, sensorineural hearing loss, and in some cases, pes cavus. This report details a case of CAPOS syndrome resulting from a maternal ATP1A3 gene mutation. Both the child and her mother exhibited symptoms post-febrile induction,including severe sensorineural hearing loss in both ears, ataxia, areflexia, and decreased vision. Additionally, the patient's mother presented with pes cavus. Genetic testing revealed a c. 2452G>A（Glu818Lys） heterozygous mutation in theATP1A3 gene in the patient . This article aims to enhance clinicians' understanding of CAPOS syndrome, emphasizing the case's clinical characteristics, diagnostic process, treatment, and its correlation with genotypeic findings.
Humans ; Child ; Female ; Cerebellar Ataxia/diagnosis* ; Talipes Cavus ; Hearing Loss, Sensorineural/diagnosis* ; Optic Atrophy/diagnosis* ; Mutation ; Phenotype ; Sodium-Potassium-Exchanging ATPase/genetics* ; Foot Deformities, Congenital ; Reflex, Abnormal

OBJECTIVE: To explore the clinical and genetic characteristics of a child with spinocerebellar ataxia type 29 (SCA29) due to novel variant of the inositol 1,4,5-trisphosphate receptor type 1 (ITPR1) gene. METHODS: The child was subjected high-throughput sequencing, and candidate variant was verified by Sanger sequencing of his family members. RESULTS: The child was found to harbor a c.800C>T (p.T267M) variant of the ITPR1 gene, which was not found in his parents and their fetus. The variant has occurred in a hotspot of the ITPR1 gene variants and was unreported before in China. Based on his clinical and genetic characteristics, the child was diagnosed with SCA29. CONCLUSION The novel heterozygous c.800C>T (p.T267M) of the ITPR1 gene probably underlay the SCA29 in this child.
Child ; Humans ; Family ; Inositol 1,4,5-Trisphosphate Receptors/genetics* ; Mutation ; Spinocerebellar Ataxias/genetics* ; Spinocerebellar Degenerations

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare and early-onset neurodegenerative disease caused by variants of the SACS gene which maps to chromosome 13q11 and encodes sacsin protein. Sacsin is highly expressed in large motor neurons, in particular cerebellar Purkinje cells. This article has provided a review for the structure and function of sacsin protein and the mechanisms underlying abnormalities of sacsin in ARSACS disease.
Humans ; Spinocerebellar Ataxias/pathology* ; Ataxia/genetics* ; Muscle Spasticity/genetics*