Adult-Onset Spinal Muscular Atrophy due to Mutations in the VRK1 Gene

ObjectiveTo expand our knowledge of the range of clinical phenotypes associated with vaccinia-related kinase 1 (VRK1) gene mutations.MethodsWe present clinical and molecular data of 2 individuals with slowly progressive weakness and a clinical syndrome consistent with adult-onset spinal muscular atrophy without pontocerebellar atrophy.ResultsGenetic testing revealed likely pathogenic variants in the VRK1 gene in both subjects. One individual carried homozygous p.R321C (c.961 C>T), likely pathogenic variants. The other carried compound heterozygous p.V236M (c.706 G>A) and p.R321C (c.961 C>T), likely pathogenic variants. Notably, both patients were of Hispanic descent.ConclusionsWe report 2 cases with VRK1 mutations presenting as adult-onset spinal muscular atrophy without pontocerebellar hypoplasia and review the current literature of similar cases. Our report expands the clinical spectrum of neurologic disorders associated with VRK1 mutations.

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Intragenic variants in the SMN1 gene determine the clinical phenotype in 5q spinal muscular atrophy

Neurology Genetics ◽

10.1212/nxg.0000000000000505 ◽

2020 ◽

Vol 6 (5) ◽

pp. e505

Author(s):

Rodrigo de Holanda Mendonça ◽

Ciro Matsui ◽

Graziela Jorge Polido ◽

André Macedo Serafim Silva ◽

Leslie Kulikowski ◽

...

Keyword(s):

Spinal Muscular Atrophy ◽

Copy Number ◽

Clinical Phenotype ◽

Muscular Atrophy ◽

Large Population ◽

Survival Motor Neuron ◽

Compound Heterozygous ◽

Pathogenic Variants ◽

Exon 1 ◽

Compound Heterozygous Variants

ObjectiveThe aim of the study was to report the proportion of homozygous and compound heterozygous variants in the survival motor neuron 1 (SMN1) gene in a large population of patients with spinal muscular atrophy (SMA) and to correlate the severity of the disease with the presence of specific intragenic variants in SMN1 and with the SMN2 copy number.MethodsFour hundred fifty Brazilian patients with SMA were included in a retrospective study, and clinical data were analyzed compared with genetic data; the SMN2 copy number was obtained by multiplex ligation-dependent probe amplification and pathogenic variants in SMN1 by next-generation sequencing.ResultsFour hundred two patients (89.3%) presented homozygous exon 7-SMN1 deletion, and 48 (10.7%) were compound heterozygous for the common deletion in one allele and a point mutation in the other allele. Recurrent variants in exons 3 and 6 (c.460C>T, c.770_780dup and c.734_735insC) accounted for almost 80% of compound heterozygous patients. Another recurrent pathogenic variant was c.5C>G at exon 1. Patients with c.770_780dup and c.734_735insC had a clinical phenotype correlated with SMN2 copy number, whereas the variants c.460C>T and c.5C>G determined a milder phenotype independently of the SMN2 copies.ConclusionsPatients with specific pathogenic variants (c.460C>T and c.5C>G) presented a milder phenotype, and the SMN2 copy number did not correlate with disease severity in this group.

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Novel compound heterozygous pathogenic variants in ASCC1 in a Chinese patient with spinal muscular atrophy with congenital bone fractures 2 : Evidence supporting a "Definitive" gene‐disease relationship

Molecular Genetics & Genomic Medicine ◽

10.1002/mgg3.1212 ◽

2020 ◽

Vol 8 (5) ◽

Author(s):

Weiliang Lu ◽

Mingxing Liang ◽

Jiasun Su ◽

Jin Wang ◽

Lingxiao Li ◽

...

Keyword(s):

Spinal Muscular Atrophy ◽

Bone Fractures ◽

Muscular Atrophy ◽

Chinese Patient ◽

Compound Heterozygous ◽

Pathogenic Variants

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Novel compound heterozygous pathogenic variants in ASCC1 in a Chinese patient with spinal muscular atrophy with congenital bone fractures 2 : evidence supporting a "Definitive" gene-disease relationship

10.21203/rs.2.19730/v1 ◽

2019 ◽

Author(s):

Weiliang Lu ◽

Mingxing Liang ◽

Jiasun Su ◽

Jin Wang ◽

Lingxiao Li ◽

...

Keyword(s):

Spinal Muscular Atrophy ◽

Exome Sequencing ◽

Disease Gene ◽

Bone Fractures ◽

Muscular Atrophy ◽

Chinese Patient ◽

Chinese Family ◽

Compound Heterozygous ◽

Pathogenic Variants ◽

Limited Spectrum

Abstract Background: A very limited spectrum of ASCC1 pathogenic variants had been reported in five (mostly consanguineous) families with spinal muscular atrophy with congenital bone fractures 2 [OMIM #616867] since 2016. Methods:A proband from a non-consanguineous Chinese family presented with neonatal severe hypotonia, respiratory distress, muscle weakness and atrophy, as well as congenital bone fractures was examined by exome sequencing. Results: A compound heterozygosity of a nonsense (c.932C>G ,p.Ser311Ter) and an exon 5 deletion in ASCC1 segregating with phenotypes was detected, both variants are novel and pathogenic. Since ASCC1 is a relative new disease gene, we performed the gene curation following ClinGen SOP. The existing evidence is sufficient to support a "Definitive" level of disease-gene relationship. Conclusion: This case report expended the mutation spectrum of ASCC1 and support the notion that this novel disease also occur in outbreed populations and this is a rare disease but may still be underdiagnosed due to its perinatal lethal outcomes. Keywords: spinal muscular atrophy with congenital bone fractures 2; ASCC1 ; compound heterozygous; gene curation; exome sequencing

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Novel compound heterozygous EYS variants may be associated with arRP in a large Chinese pedigree

Bioscience Reports ◽

10.1042/bsr20193443 ◽

2020 ◽

Vol 40 (6) ◽

Cited By ~ 1

Author(s):

Chunli Wei ◽

Ting Xiao ◽

Jingliang Cheng ◽

Jiewen Fu ◽

Qi Zhou ◽

...

Keyword(s):

Novel Mutation ◽

Gene Mutations ◽

Chinese Family ◽

Compound Heterozygous ◽

Missense Mutations ◽

The Novel ◽

Pathogenic Variants ◽

Pathogenic Genes ◽

Compound Heterozygous Variants ◽

Normal Controls

Abstract As a genetically heterogeneous ocular dystrophy, gene mutations with autosomal recessive retinitis pigmentosa (arRP) in patients have not been well described. We aimed to detect the disease-causing genes and variants in a Chinese arRP family. In the present study, a large Chinese pedigree consisting of 31 members including a proband and another two patients was recruited; clinical examinations were conducted; next-generation sequencing using a gene panel was used for identifying pathogenic genes, and Sanger sequencing was performed for verification of mutations. Novel compound heterozygous variants c.G2504A (p.C835Y) and c.G6557A (p.G2186E) for the EYS gene were identified, which co-segregated with the clinical RP phenotypes. Sequencing of 100 ethnically matched normal controls didn’t found these mutations in EYS. Therefore, our study identified pathogenic variants in EYS that may cause arRP in this Chinese family. This is the first study to reveal the novel mutation in the EYS gene (c.G2504A, p.C835Y), extending its mutation spectrum. Thus, the EYS c.G2504A (p.C835Y) and c.G6557A (p.G2186E) variants may be the disease-causing missense mutations for RP in this large arRP family. These findings should be helpful for molecular diagnosis, genetic counseling and clinical management of arRP disease.

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Genomic analysis of a spinal muscular atrophy (SMA) discordant family identifies a novel mutation in TLL2, an activator of growth differentiation factor 8 (myostatin): a case report

BMC Medical Genetics ◽

10.1186/s12881-019-0935-3 ◽

2019 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Jianping Jiang ◽

Jinwei Huang ◽

Jianlei Gu ◽

Xiaoshu Cai ◽

Hongyu Zhao ◽

...

Keyword(s):

Spinal Muscular Atrophy ◽

De Novo ◽

Muscular Atrophy ◽

Novel Mutation ◽

Genomic Analysis ◽

Neuromuscular Disorder ◽

De Novo Mutation ◽

Compound Heterozygous ◽

Mice Model ◽

Compound Heterozygous Mutations

Abstract Background Spinal muscular atrophy (SMA) is a rare neuromuscular disorder threating hundreds of thousands of lives worldwide. And the severity of SMA differs among different clinical types, which has been demonstrated to be modified by factors like SMN2, SERF1, NAIP, GTF2H2 and PLS3. However, the severities of many SMA cases, especially the cases within a family, often failed to be explained by these modifiers. Therefore, other modifiers are still waiting to be explored. Case presentation In this study, we presented a rare case of SMA discordant family with a mild SMA male patient and a severe SMA female patient. The two SMA cases fulfilled the diagnostic criteria defined by the International SMA Consortium. With whole exome sequencing, we confirmed the heterozygous deletion of exon7 at SMN1 on the parents’ genomes and the homozygous deletions on the two patients’ genomes. The MLPA results confirmed the deletions and indicated that all the family members carry two copies of SMN2, SERF1, NAIP and GTF2H2. Further genomic analysis identified compound heterozygous mutations at TLL2 on the male patient’s genome, and compound heterozygous mutations at VPS13A and the de novo mutation at AGAP5 on female patient’s genome. TLL2 is an activator of myostatin, which negatively regulates the growth of skeletal muscle tissue. Mutation in TLL2 has been proved to increase muscular function in mice model. VPS13A encodes proteins that control the cycling of proteins through the trans-Golgi network to endosomes, lysosomes and the plasma membrane. And AGAP5 was reported to have GTPase activator activity. Conclusions We reported a case of SMA discordant family and identified mutations at TLL2, VPS13A and AGAP5 on the patients’ genomes. The mutations at TLL2 were predicted to be pathogenic and are likely to alleviate the severity of the male SMA patient. Our finding broadens the spectrum of genetic modifiers of SMA and will contribute to accurate counseling of SMA affected patients and families.

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