A VPS13B mutation in Cohen syndrome presented with petechiae: An unusual presentation.
Ontology highlight
ABSTRACT:
SUBMITTER: Razavi A
PROVIDER: S-EPMC8301562 | biostudies-literature | 2021 Jul
REPOSITORIES: biostudies-literature
Publications
A VPS13B mutation in Cohen syndrome presented with petechiae: An unusual presentation.
Razavi Alireza A Jafarpour Hamed H Khosravi Mohammad Reza MR Abbasi Ghazal G Dabbaghzadeh Abbas A
Clinical case reports 20210723 7
Cohen syndrome (CS) is a rare autosomal recessive disorder. CS includes a range of clinical symptoms including retinal dystrophy and myopia. The new VPS13B mutation could cause CS-induced neutropenia and petechiae in patients with CS. ...[more]
Similar Datasets
Project description:BackgroundCohen syndrome, an autosomal recessive syndrome, is a rare syndrome with diverse clinical manifestations including failure to thrive, hypotonia, hypermobile joints, microcephaly, intellectual disabilities, craniofacial and limb anomalies, neutropenia and a friendly character. It is associated with mutations of the vacuolar protein sorting 13 homolog B (VPS13B) gene, which is involved in the development of the ocular, hematological and central nervous systems. This gene encodes a transmembrane protein playing a crucial role in preserving the integrity of the Golgi complex. To date, more than 150 mutations of VPS13B have been reported in over 200 Cohen syndrome patients. Missense or nonsense mutations are the most common mutations.Case presentationA 4-year-old girl, born to consanguineous parents, was referred to the pediatric clinical immunology outpatient clinic for investigation of recurrent neutropenia with a history of recurrent infections in the past year. On physical examination, she had the characteristic facial features of Cohen syndrome, developmental delay and speech disorder. She had a cheerful disposition, and her mother gave a history of feeding difficulties in her first months of life. She did not present any ophthalmologic or cardiac abnormalities. Her lab results revealed moderate neutropenia. Serum IgG, IgM, IgA and IgE levels were normal. She fulfilled the clinical diagnostic criteria for Cohen syndrome. WES revealed a novel homozygous frameshift variant in VPS13B (LRG_351t1: c.7095del; p.Ser2366AlafsTer49). Currently, she is not experiencing any severe problem, and she undergoes irregular medical treatment once her neutrophil count decreases under the normal limit. Her verbal and motor abilities have improved as a result of speech and occupational therapies.ConclusionWe reported a novel homozygous frameshift variant in VPS13B (LRG_351t1: c.7095del; p.Ser2366AlafsTer49) in a 4-year-old girl with Cohen syndrome. Cohen syndrome should be considered in differential diagnosis of any child with intellectual disability and neutropenia.
| S-EPMC7325105 | biostudies-literature
Project description:We have earlier described a syndrome characterized by microcephaly, cutis verticis gyrata, retinitis pigmentosa, cataracts, hearing loss and mental retardation (Mendelian inheritance in man (MIM) no: 605685) in two brothers from a non-consanguineous Lebanese family. In view of the rarity of the disorder and the high rate of inbreeding in the Lebanese population, we assumed an autosomal recessive trait inherited from a common ancestor. A genomewide scan was performed. The single locus on the long arm of chromosome 8 that showed homozygosity by descent comprised the gene responsible for Cohen syndrome (CS), VPS13B. We then sequenced VPS13B in the patients and found a homozygous splice site mutation. Several possible explanations for the overlap between CS and the clinical features observed in our patients are discussed. Our data highlight the potential of high-resolution homozygosity mapping in small populations with a high rate of inbreeding.
| S-EPMC2986550 | biostudies-literature
Project description:Pathogenic variants in vacuolar protein sorting 13 homolog B (VPS13B) cause Cohen syndrome (CS), a clinically diverse neurodevelopmental disorder. We used whole exome and Sanger sequencing to identify disease-causing variants in a Pakistani family with intellectual disability, microcephaly, facial dysmorphism, neutropenia, truncal obesity, speech delay, motor delay, and insomnia. We identified a novel homozygous nonsense variant c.8841G > A: p.(W2947∗) in VPS13B (NM_017890.5) which segregated with the disease. Sleep disturbances are commonly seen in neurodevelopmental disorders and can exacerbate medical issues if left untreated. We demonstrate that individuals with Cohen syndrome may also be affected by sleep disturbances. In conclusion, we expand the genetic and phenotypic features of Cohen syndrome in the Pakistani population.
| S-EPMC10115529 | biostudies-literature
Project description:Autosomal recessive Cohen syndrome is a neurodevelopmental disorder characterized by postnatal microcephaly, intellectual disability, and a typical facial gestalt. Genetic variants in VPS13B have been found to cause Cohen syndrome, but have also been linked to autism, retinal disease, primary immunodeficiency, and short stature. While it is well established that loss-of-function mutations of VPS13B cause Cohen syndrome, the relevance of missense variants for the pathomechanism remains unexplained. Here, we investigate their pathogenic effect through a systematic re-evaluation of clinical patient information, comprehensive in silico predictions, and in vitro testing of previously published missense variants. In vitro analysis of 10 subcloned VPS13B missense variants resulted in full-length proteins after transient overexpression. 6/10 VPS13B missense variants show reduced accumulation at the Golgi complex in the steady state. The overexpression of these 6/10 VPS13B missense variants did not rescue the Golgi fragmentation after the RNAi-mediated depletion of endogenous VPS13B. These results thus validate 6/10 missense variants as likely pathogenic according to the classification of the American College of Medical Genetics through the integration of clinical, genetic, in silico, and experimental data. In summary, we state that exact variant classification should be the first step towards elucidating the pathomechanisms of genetically inherited neuronal diseases.
| S-EPMC9188546 | biostudies-literature
Project description:BackgroundCohen syndrome (OMIM No. # 216550) is a rare autosomal recessive disorder caused by homozygous mutation in the vacuolar protein sorting 13 homolog B (VPS13B) gene on chromosome 8q22.2. Clinical manifestations include hypermobile joints, microcephaly, intellectual disabilities, craniofacial and limb anomalies, and neutropenia. To date, more than 200 mutations of VPS13B have been reported in over 1,000 Cohen syndrome patients. This article reviews the clinical data of two cases of Cohen syndrome diagnosed by whole exome sequencing.ResultsBoth children visited for psychomotor retardation. Gene detection showed a mutation in 8q22.2, NM_017890.4 Intron38 c.6940+1G > T and heterozygotic deletion of exon 3-19 of the VPS13B gene (Case 1), and a mutation in 8q22.2, NM_017890.4 Intron38 c.6940+1G > T and 8q22, NM_017890.4 Exon56 c10334_10335del in the VPS13B gene (Case 2). The variation was predicted to be pathogenic by related software, and they have not been reported.ConclusionCohen syndrome should be considered in the differential diagnosis of any child with developmental retardation and neutropenia. The present study increases the mutation spectrum of the VPS13B gene and could be helpful in genetic diagnosis and genetic counseling in Cohen syndrome patients.
| S-EPMC10487392 | biostudies-literature
Project description:BackgroundCohen syndrome is a rare autosomal recessive developmental disorder that comprises variable clinical features counting developmental delay, pigmentary retinopathy, myopia, acquired microcephaly, truncal obesity, joint hypermobility, friendly disposition and intermittent neutropenia. VPS13B (vacuolar protein sorting 13, yeast, homologue of B) gene is the only gene responsible for Cohen Syndrome, causative mutations include nonsense, missense, indel and splice-site variants. The integrity of the Golgi apparatus requires the presence of the peripheral membrane protein VPS13B that have an essential function in intracellular protein transport and vesicle-mediated sorting.Case presentationIn this study, we performed whole exome sequencing (WES) in a Tunisian family with two young cases having developmental delay, hypotonia, autism spectrum disorder, ptosis and thick hair and eyebrows. The proposita presented also pigmentory retinopathy. Compound heterozygous mutation in VPS13B gene was detected by WES. This mutation inherited from healthy heterozygous parents, supports an unpredictable clinical diagnosis of Cohen Syndrome. The proband's phenotype is explained by the presence of compound heterozygous mutations in the VPS13B gene. This finding refined the understanding of genotype-phenotype correlation.ConclusionsThis is the first report of a Tunisian family with Cohen syndrome mutated in the VPS13B gene.
| S-EPMC5693559 | biostudies-literature
Project description:Background: Cohen syndrome (CS) is a clinically heterogeneous disorder characterized by extensive phenotypic variation with autosomal recessive inheritance. VPS13B was identified to be the disease-causing gene for CS. The objectives of the present study were to screen likely pathogenic mutations of the patient with developmental delay and mental retardation, and to determinate the effect of this splice-site mutation by reverse transcription analysis. Methods: Whole exome sequencing (WES) in combination with Sanger sequencing were performed to identify the causative mutations of this CS family. Subsequently, the impact of the intronic variant on splicing was analyzed by reverse transcription and the construction of expression vector. Results: A novel homozygous splice-site mutation (c.6940+1G>T) in the VPS13B gene was identified in this proband. Sanger sequencing analysis of the cDNA demonstrated that the c.6940+1G>T variant could cause the skipping of entire exon 38, resulting in the loss of 208 nucleotides and further give rise to the generation of a premature in-frame stop codon at code 2,247. Conclusions: The homozygous VPS13B splicing variant c.6940+1G>T was co-segregated with the CS phenotypes in this family and was identified to be the cause of CS after comprehensive consideration of the clinical manifestations, genetic analysis and cDNA sequencing result.
| S-EPMC8093766 | biostudies-literature
Project description:BACKGROUND:Cohen syndrome (CS) is an uncommon developmental disease with evident clinical heterogeneity. VPS13B is the only gene responsible for CS. Only few sporadic cases of CS have been reported in China. CASE PRESENTATION:A Chinese family with two offspring-patients affected by developmental delay and intellectual disability was investigated in this study. Exome sequencing was performed, and compound heterozygous mutations in VPS13B were segregated for family members with autosomal recessive disorder. Splicing mutation c.3666 + 1G > T (exon 24) and nonsense mutation c. 9844 A > T:p.K3282X (exon 54) were novel. We revisited the family and learned that both patients are affected by microcephaly, developmental delay, neutropenia, and myopia and have a friendly disposition, all of which are consistent with CS phenotypes. We also found that both patients have hyperlinear palms, which their parents do not have. VPS13B mutations reported among the Chinese population were reviewed accordingly. CONCLUSIONS:This study presents two novel VPS13B mutations in CS. The identification of hyperlinear palms in a family affected by CS expands the phenotype spectrum of CS.
| S-EPMC6873578 | biostudies-literature
Project description:Significant clinical symptoms of Cohen syndrome (CS), a rare autosomal recessive disorder, include intellectual disability, facial dysmorphism, postnatal microcephaly, retinal dystrophy, and intermittent neutropenia. CS has been associated with mutations in the VPS13B (vacuolar protein sorting 13 homolog B) gene, which regulates vesicle-mediated protein sorting and transport; however, the cellular mechanism underlying CS pathogenesis in patient-derived neurons remains uncertain. This report states that autophagic vacuoles accumulate in CS fibroblasts and the axonal terminals of CS patient-specific induced pluripotent stem cells (CS iPSC)-derived neurons; additionally, autophagic flux was significantly increased in CS-derived neurons compared to control neurons. VPS13B knockout HeLa cell lines generated using the CRISPR/Cas9 genome editing system showed significant upregulation of autophagic flux, indicating that VSP13B may be associated with autophagy in CS. Transcriptomic analysis focusing on the autophagy pathway revealed that genes associated with autophagosome organization were dysregulated in CS-derived neurons. ATG4C is a mammalian ATG4 paralog and a crucial regulatory component of the autophagosome biogenesis/recycling pathway. ATG4C was significantly upregulated in CS-derived neurons, indicating that autophagy is upregulated in CS neurons. The autophagy pathway in CS neurons may be associated with the pathophysiology exhibited in the neural network of CS patients.
| S-EPMC7203861 | biostudies-literature
Project description:Cohen syndrome (CS) is a rare multisystem autosomal recessive disorder associated with mutations in VPS13B (vacuolar protein sorting homolog 13B). The NAPB-related neurodevelopmental disorder is characterized mainly by early-onset epileptic encephalopathy (EOEE) and is associated with mutations in NAPB that encodes for SNAP-beta (soluble NSF attachment protein beta). Here we describe male triplets, clinically presenting with the phenotype of subtle but distinctive facial features, intellectual disability, increased body weight, neonatal EOEE, and prominently variable abnormal behaviors of autism and sexual arousal. The EEG showed multifocal epilepsy, while the brain MRI showed no abnormalities. Diagnostic exome sequencing (ES), the applied next-generation sequencing approach, revealed the interesting finding of two novel homozygous variants in two genes: VPS13B missense variant (c.8516G > A) and NAPB splice-site loss (c.354 + 2 T > G). Sanger sequencing verified the segregation of the two recessive gene variants with the phenotype in family members. The prediction algorithms support the pathogenicity of these variants. Homozygosity mapping of ES data of this consanguineous family revealed multiple chromosomal regions of homozygosity stretches with the residing of VPS13B (chr8: 100830758G > A) and NAPB (Chr20: 23,375,774 A > C) variants within the largest homozygous blocks further supporting the disease-genes causal role. Interestingly, the functions of the two proteins; VPS13B, a transmembrane protein involved in intracellular protein transport, and SNAP-beta involved in neurotransmitters release at the neuronal synaptic complexes, have been associated with Golgi-mediated vesicular trafficking. Our ES findings provide new insights into the pathologic mechanism underlying the expansion of the neurodevelopmental spectrum in CS and further highlight the importance of Golgi and Golgi-membrane-related proteins in the development of neurodevelopmental syndromes associated with early-onset non-channelopathy epilepsy. To our knowledge, this is the first report documenting multifocal EOEE in CS patients with the association of a pathogenic NAPB variant.
| S-EPMC10063482 | biostudies-literature