scholarly journals 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

2019 ◽  
Vol 20 (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.

scholarly journals A Novel De Novo Variant in DYNC1H1 Causes Spinal Muscular Atrophy Lower Extremity Predominant in Identical Twins: A Case Report

2021 ◽  
Vol 8 ◽  
pp. 2329048X2110274
Author(s):  
Alexa Derksen ◽  
Amytice Mirchi ◽  
Luan T. Tran ◽  
Lei Cao-Lei ◽  
Maryam Oskoui ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Motor Neurons ◽  
De Novo ◽  
Muscular Atrophy ◽  
Monozygotic Twins ◽  
Neuromuscular Disorder ◽  
Predominant Type ◽  
De Novo Variant

Mutations in DYNC1H1 have been shown to cause spinal muscular atrophy lower extremity predominant type 1 (SMALED1), an autosomal dominant genetic neuromuscular disorder characterized by degeneration of spinal cord motor neurons resulting in muscle weakness. Here, we describe monozygotic twins, one with a more severe upper motor neuron phenotype as a result of a suspected perinatal hypoxic-ischemic event and the other presenting a typical lower motor neuron phenotype. Using exome sequencing, we identified the novel de novo variant c.752G>T; p.Arg251Leu in DYNC1H1. We thereby add this variant to the growing list of mutations in DYNC1H1 that cause SMALED1.

scholarly journals P.068 Abnormal fatty acid metabolism is a feature of spinal muscular atrophy

2019 ◽  
Vol 46 (s1) ◽  
pp. S32
Author(s):  
M Deguise ◽  
A Beauvais ◽  
G Baranello ◽  
C Pileggi ◽  
C Mastella ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
High Resolution ◽  
Mouse Model ◽  
Spinal Muscular Atrophy ◽  
Muscular Atrophy ◽  
Liver Steatosis ◽  
Neuromuscular Disorder ◽  
Glycogen Depletion ◽  
Preclinical Animal Models

Background: Spinal muscular atrophy (SMA) is a children’s neuromuscular disorder. Although motor neuron loss is a major feature of the disease, we have identified fatty acid abnormalities in SMA patients and in preclinical animal models, suggesting metabolic perturbation is also an important component of SMA. Methods: Biochemical, histological, proteomic, and high resolution respirometry were used. Results: SMA patients are more susceptible to dyslipidemia than the average population as determined by a standard lipid profile in a cohort of 72 pediatric patients. As well, we observed a non-alcoholic liver disease phenotype in apreclinical mouse model. Denervation alone was not sufficient to induce liver steatosis, as a mouse model of ALS, did not develop fatty liver. Hyperglucagonemia in Smn2B/-mice could explain the hepatic steatosis by increasing plasma substrate availability via glycogen depletion and peripheral lipolysis. Proteomic analysis identified mitochondrion and lipid metabolism as major clusters. Alterations in mitochondrial function were revealed by high-resolution respirometry. Finally, low-fat diets led to increased survival in Smn2B/-mice. Conclusions: These results provide strong evidence for lipid metabolism defects in SMA. Further investigation will be required to establish the primary mechanism of these alterations and understand how they lead to additional co-morbidities in SMA patients.

scholarly journals De novo variant in KIF26B is associated with pontocerebellar hypoplasia with infantile spinal muscular atrophy

2018 ◽  
Vol 176 (12) ◽  
pp. 2623-2629 ◽  
Author(s):  
Monica H. Wojcik ◽  
Kyoko Okada ◽  
Sanjay P. Prabhu ◽  
Dan W. Nowakowski ◽  
Keri Ramsey ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
De Novo ◽  
Muscular Atrophy ◽  
Pontocerebellar Hypoplasia ◽  
De Novo Variant

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

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.

scholarly journals RESTORE: A Prospective Multinational Registry of Patients with Genetically Confirmed Spinal Muscular Atrophy - Rationale and Study Design

2020 ◽  
Vol 7 (2) ◽  
pp. 145-152 ◽  
Author(s):  
Richard S. Finkel ◽  
John W. Day ◽  
Darryl C. De Vivo ◽  
Janbernd Kirschner ◽  
Eugenio Mercuri ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
De Novo ◽  
Muscular Atrophy ◽  
Work Productivity ◽  
Healthcare Resource Utilization ◽  
Real World Data ◽  
Activity Impairment ◽  
Survival Status ◽  
Usual Clinical Practice

Background: Dramatic improvements in spinal muscular atrophy (SMA) treatment have changed the prognosis for patients with this disease, leading to important new questions. Gathering representative, real-world data about the long-term efficacy and safety of emerging SMA interventions is essential to document their impact on patients and caregivers. Objectives: This registry will assess outcomes in patients with genetically confirmed SMA and provide information on the effectiveness and long-term safety of approved and emerging treatments. Design and Methods: RESTORE is a prospective, multicenter, multinational observational registry. Patients will be managed according to usual clinical practice. Both newly recruitedSMAtreatment centers and sites involved in existing SMA registries, including iSMAC, Treat-NMD, French SMA Assistance Publique- Hôpitaux de Paris (AP-HP), Cure-SMA, SMArtCARE, will be eligible to participate; de novo; sites already participating in another registry may be included via consortium agreements. Data from patients enrolled in partnering registries will be shared with the RESTORE Registry and data for newly diagnosed patients will be added upon enrollment. Patients will be enrolled over a 5-year period and followed for 15 years or until death. Assessments will include SMA history and treatment, pulmonary, nutritional, and motor milestones, healthcare resource utilization, work productivity, activity impairment, adverse events, quality of life, caregiver burden, and survival. Status: Recruitment started in September 2018. As of January 3, 2020, 64 patients were enrolled at 25 participating sites. Conclusions: The RESTORE Registry has begun recruiting recently diagnosed patients with genetically confirmed SMA, enabling assessment of both short- and long-term patient outcomes.

scholarly journals Spinal Muscular Atrophy Type 3: A Case Report

2020 ◽  
Vol 43 (3) ◽  
pp. 183-187
Author(s):  
Maria Kibtiar ◽  
Roksana Parvin ◽  
Manik Kumar Talukder ◽  
Choudhury Ali Kawser
Keyword(s):  
Spinal Muscular Atrophy ◽  
Motor Neurons ◽  
Muscular Atrophy ◽  
Neuromuscular Disorder ◽  
Proximal Muscle Weakness ◽  
Proximal Muscle ◽  
Spinal Muscular Atrophy Type ◽  
Genetically Determined ◽  
Type 3 ◽  
Tendon Reflexes

Spinal muscular atrophy (SMA) type 3 is a relatively stable genetically determined chronic neuromuscular disorder caused by degeneration of motor neurons of spinal cord. Patients with type 3 SMA may gradually experience decline in muscle strength and motor function. However functional progression is difficult to document and mechanisms remain poorly understood. A five years old boy presented with proximal muscle weakness, generalized hypotonia, absent deep tendon reflexes and features of neuropathy and labeled as SMA type 3. Bangladesh J Child Health 2019; VOL 43 (3) :183-187

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