scholarly journals 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

2020 ◽  
Vol 8 (5) ◽  
Author(s):  
Weiliang Lu ◽  
Mingxing Liang ◽  
Jiasun Su ◽  
Jin Wang ◽  
Lingxiao Li ◽  
...  
2019 ◽  
Author(s):  
Weiliang Lu ◽  
Mingxing Liang ◽  
Jiasun Su ◽  
Jin Wang ◽  
Lingxiao Li ◽  
...  

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


2020 ◽  
Vol 6 (5) ◽  
pp. e505
Author(s):  
Rodrigo de Holanda Mendonça ◽  
Ciro Matsui ◽  
Graziela Jorge Polido ◽  
André Macedo Serafim Silva ◽  
Leslie Kulikowski ◽  
...  

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.


2021 ◽  
Vol 7 (4) ◽  
pp. e599
Author(s):  
Angela Sung ◽  
Paolo Moretti ◽  
Aziz Shaibani

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.


2016 ◽  
Vol 98 (3) ◽  
pp. 473-489 ◽  
Author(s):  
Ellen Knierim ◽  
Hiromi Hirata ◽  
Nicole I. Wolf ◽  
Susanne Morales-Gonzalez ◽  
Gudrun Schottmann ◽  
...  

2022 ◽  
pp. 097321792110688
Author(s):  
Francisco Ribeiro-Mourão ◽  
Ana Vilan ◽  
Sara Passos-Silva ◽  
Fernando Silveira ◽  
Miguel Leão ◽  
...  

Arthrogryposis multiplex congenita (AMC) is a heterogeneous condition comprising congenital multiple joint contractures, and it is secondary to decreased fetal mobility following environmental/genetic abnormalities. BICD2 pathogenic variants have been associated with autosomal dominant spinal muscular atrophy with lower extremity predominance (SMALED2). We report the case of a newborn with decreased fetal movements and ventriculomegaly diagnosed in utero, born with severe AMC, multiple bone fractures, congenital hip dislocation, and respiratory insufficiency that led to neonatal death. His mother had AMC diagnosis without established etiology. Her phenotype characterization was key to guide the genetic investigation. A BICD 2 heterozygous variant (NM_001003800.1; c.2080C > T; p. [Arg694Cys]) was detected both in the mother and the newborn. This variant had previously been reported in 3 cases, all having de novo severe SMALED-type 2B (MIM#618291) phenotype. This is the first report of this variant (p. [Arg694Cys]) presenting with an inherited, severe, and lethal phenotype associated to intrafamilial variability, suggesting a more complex phenotype-genotype correlation than previously stated.


2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Jianping Jiang ◽  
Jinwei Huang ◽  
Jianlei Gu ◽  
Xiaoshu Cai ◽  
Hongyu Zhao ◽  
...  

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.


2004 ◽  
Vol 107 (5) ◽  
pp. 475-478 ◽  
Author(s):  
M. A. Garc�a-Cabezas ◽  
A. Garc�a-Alix ◽  
Y. Mart�n ◽  
M. Guti�rrez ◽  
C. Hern�ndez ◽  
...  

2018 ◽  
Vol 5 ◽  
pp. 2329048X1876981 ◽  
Author(s):  
Annie Ting Gee Chiu ◽  
Sophelia Hoi Shan Chan ◽  
Shun Ping Wu ◽  
Shun Hin Ting ◽  
Brian Hon Yin Chung ◽  
...  

The authors report a child with spinal muscular atrophy with respiratory distress type 1 (SMARD1). She presented atypically with hypothyroidism and heart failure due to septal defects that required early heart surgery and microcephaly in association with cerebral atrophy and thin corpus collosum. The subsequent asymmetrical onset of diaphragmatic paralysis, persistent hypotonia, and generalized muscle weakness led to the suspicion of spinal muscular atrophy with respiratory distress type 1. Sanger sequencing confirmed a compound heterozygous mutation in the Immunoglobulin Mu Binding Protein 2 (IGHMBP2) gene, with a known mutation c.2362C > T (p.Arg788*) and a novel frameshift mutation c.2048delG (p.Gly683A1afs*50). Serial nerve conduction study and electromyography confirmed progressive sensorimotor polyneuropathy and neuronopathy. In summary, this case report describes a child with spinal muscular atrophy with respiratory distress type 1 also with congenital cardiac disease and endocrine dysfunction, expanding the phenotypic spectrum of this condition. A high index of suspicion is needed in diagnosing this rare condition to guide the management and genetic counseling.


2019 ◽  
Author(s):  
Jianbo Shu ◽  
Jingrui Wang ◽  
Yulian Fang ◽  
Zanmei Xu ◽  
Xiaowei Wang ◽  
...  

Abstract Background Some spinal muscular atrophy (SMA) cases are caused by either compound heterozygosity with a point mutation in one allele and a deletion in the other or compound heterozygous point mutations in SMN1 or other genes. Methods To explore more genes and mutations in the onset of SMA, 83 whole blood samples were collected from 28 core families of clinically suspected SMA, and multiplex ligation probe amplification (MLPA) was firstly performed with a SALSA MLPA Kit P021 for preliminary diagnosis. Afterwards, the complete gene sequence of SMN1 gene was detected with the high-throughput sequencing platform of Illumina HiSeq-2500 to find more mutations in the 28 core families. Furthermore, 20 SMA patients were selected from the 28 prodands, and 5 non SMA children as controls. The Life Technologies SOLiD™ technology with mate-pair chemistry was utilized to conduct the whole exome high-throughput sequencing. Results MLPA results showed that 22 probands were SMA patients, 3 probands carriers, and 3 probands normal individuals. Moreover, 2 parents from 2 SMA families were with 3 SMN1 exon7 copies. 6 SMN1 single nucleotide variants (SNVs) were identified in the 83 samples, and c.[84C>T], c.[271C>T], c.[-39A>G] and g.[70240639G>C] were novel. Compared with control group, 9102 mutation were selected out in SMA patients. SPTA1 mutation c.[-41_-40insCTCT], FUT5 SNV c.[1001A>G], and MCCC2 SNV c.[-117A>G] were the 3 most frequent mutations in SMA group (95%, 85% and 75%, respectively). Conclusions We identified some mutations in both SMN1 and other genes, and c.[271C>T], c.[-41_-40insCTCT], c.[1001A>G] and c.[-117A>G] might be associated with the onset of SMA.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Cong Zhou ◽  
Yuanyuan Xiao ◽  
Hanbing Xie ◽  
Shanling Liu ◽  
Jing Wang

Abstract Background Usher syndrome (USH) is the most common cause of inherited deaf-blindness. The current study aimed to identify pathogenic variants in a Chinese patient with hearing loss and to report the identification of a novel p.(Phe1583Leufs*10) variant in USH2A, which met the needs of prenatal diagnosis of the patient's mother. Case presentation Genomic DNA obtained from a five-year-old girl with hearing loss was analyzed via the hearing loss-targeted gene panels. We identified the compound heterozygous variants c.8559-2A>G and c.4749delT in Usher syndrome type 2A (USH2A) gene as the underlying cause of the patient; the former variation has been reported in the literature, but not the latter. The parents of the girl were heterozygous carriers. The two variants were classified as pathogenic. Based on these findings, amniotic fluid samples were used for prenatal diagnosis of the couple's fetus, which was found to carry c.4749delT but not c.8559-2A>G variation. During the follow-up period of more than 9 months after the birth of the fetus, it was confirmed that the infant was healthy. Conclusions The results of the present study identified two compound heterozygous USH2A variants in a patient with hearing loss and reported a novel USH2A variant which expands the spectrum of USH2A variants in USH.


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