scholarly journals Targeted Next-Generation Sequencing Reveals Mutations in Non-coding Regions and Potential Regulatory Sequences of Calpain-3 Gene in Polish Limb–Girdle Muscular Dystrophy Patients

2021 ◽  
Vol 15 ◽  
Author(s):  
Anna Macias ◽  
Jakub Piotr Fichna ◽  
Malgorzata Topolewska ◽  
Maria J. Rȩdowicz ◽  
Anna M. Kaminska ◽  
...  

Limb–girdle muscular dystrophy type R1 (LGMDR1) is caused by mutations in CAPN3 and is the most common type of recessive LGMD. Even with the use of whole-exome sequencing (WES), only one mutant allele of CAPN3 is found in a significant number of LGMDR patients. This points to a role of non-coding, intronic or regulatory, sequence variants in the disease pathogenesis. Targeted sequencing of the whole CAPN3 gene including not only intronic, 3′ and 5′ UTRs but also potential regulatory regions was performed in 27 patients suspected with LGMDR1. This group included 13 patients with only one mutated CAPN3 allele detected previously with exome sequencing. A second rare variant in the non-coding part of CAPN3 was found in 11 of 13 patients with previously identified single mutation. Intronic mutations were found in 10 cases, with c.1746-20C>G variant present in seven patients. In addition, a large deletion of exons 2–8 was found in one patient. In the patients with no causative mutation previously found, we detected rare CAPN3 variants in 5 out of 10 patients and in two of them in a compound heterozygous state. Rare variants within putative regulatory sequences distant from the CAPN3 gene were found in 15 patients, although in 11 of these cases, other variants are deemed causative. The results indicate that intronic mutations are common in Polish LGMDR patients, and testing for non-coding mutations in CAPN3 should be performed in apparently single heterozygous patients.

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Evelina Siavrienė ◽  
Gunda Petraitytė ◽  
Birutė Burnytė ◽  
Aušra Morkūnienė ◽  
Violeta Mikštienė ◽  
...  

Abstract Background Autosomal recessive limb–girdle muscular dystrophy-1 (LGMDR1), also known as calpainopathy, is a genetically heterogeneous disorder characterised by progression of muscle weakness. Homozygous or compound heterozygous variants in the CAPN3 gene are known genetic causes of this condition. The aim of this study was to confirm the molecular consequences of the CAPN3 variant NG_008660.1(NM_000070.3):c.1746-20C > G of an individual with suspected LGMDR1 by extensive complementary DNA (cDNA) analysis. Case presentation In the present study, we report on a male with proximal muscular weakness in his lower limbs. Compound heterozygous NM_000070.3:c.598_612del and NG_008660.1(NM_000070.3):c.1746-20C > G genotype was detected on the CAPN3 gene by targeted next-generation sequencing (NGS). To confirm the pathogenicity of the variant c.1746-20C > G, we conducted genetic analysis based on Sanger sequencing of the proband’s cDNA sample. The results revealed that this splicing variant disrupts the original 3′ splice site on intron 13, thus leading to the skipping of the DNA fragment involving exon 14 and possibly exon 15. However, the lack of exon 15 in the CAPN3 isoforms present in a blood sample was explained by cell-specific alternative splicing rather than an aberrant splicing mechanism. In silico the c.1746-20C > G splicing variant consequently resulted in frameshift and formation of a premature termination codon (NP_000061.1:p.(Glu582Aspfs*62)). Conclusions Based on the results of our study and the literature we reviewed, both c.598_612del and c.1746-20C > G variants are pathogenic and together cause LGMDR1. Therefore, extensive mRNA and/or cDNA analysis of splicing variants is critical to understand the pathogenesis of the disease.


2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Amjad Khan ◽  
Rongrong Wang ◽  
Shirui Han ◽  
Muhammad Umair ◽  
Safdar Abbas ◽  
...  

Abstract Background Limb-girdle muscular dystrophies (LGMDs) are large group of heterogeneous genetic diseases, having a hallmark feature of muscle weakness. Pathogenic mutations in the gene encoding the giant skeletal muscle protein titin (TTN) are associated with several muscle disorders, including cardiomyopathy, recessive congenital myopathies and limb-girdle muscular dystrophy (LGMD) type10. The phenotypic spectrum of titinopathies is expanding, as next generation sequencing (NGS) technology makes screening of this large gene possible. Aim This study aimed to identify the pathogenic variant in a consanguineous Pakistani family with autosomal recessive LGMD type 10. Methods DNA from peripheral blood samples were obtained, whole exome sequencing (WES) was performed and several molecular and bioinformatics analysis were conducted to identify the pathogenic variant. TTN coding and near coding regions were further amplified using PCR and sequenced via Sanger sequencing. Results Whole exome sequencing analysis revealed a novel homozygous missense variant (c.98807G > A; p.Arg32936His) in the TTN gene in the index patients. No heterozygous individuals in the family presented LGMD features. The variant p.Arg32936His leads to a substitution of the arginine amino acid at position 32,936 into histidine possibly causing LGMD type 10. Conclusion We identified a homozygous missense variant in TTN, which likely explains LGMD type 10 in this family in line with similar previously reported data. Our study concludes that WES is a successful molecular diagnostic tool to identify pathogenic variants in large genes such as TTN in highly inbred population.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Melissa L. Cox ◽  
Jacquelyn M. Evans ◽  
Alexander G. Davis ◽  
Ling T. Guo ◽  
Jennifer R. Levy ◽  
...  

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Hadis Malek ◽  
Khadijeh Shahrokhabadi ◽  
Saeid Ghavami ◽  
Mohsen Taheri ◽  
Ehsan Ghayoor Karimiani

Introduction: Muscular dystrophy is a hereditary degenerative muscle disease which progressively reduces the strength of the muscles that control movement. In this study, we tried to investigate genetic variants in muscular dystrophy using sequencing of whole exons. Case Presentation: A family with two affected patients with muscular dystrophy was referred for genetic counseling followed by exome sequencing testing on the proband. After filling out informed consent, blood samples were obtained from each available family member. Candidate genetic variant was confirmed using Sanger sequencing. Conclusions: Exome data analysis revealed a variant of c.2864 + 1G > A in the proband, which altered the exon-intron 26 splice site within the DYSF gene. Genetic changes in this gene are known to be associated with muscular disorders, such as limb-girdle muscular dystrophy and other dysferlinopathies. Assessment of this genetic variant in the patient's sister also showed homozygous variant. Since the patient's sister was married to her cousin, the same variant was tested in her husband, which was normal homozygous. NGS-based techniques, including whole-exome sequencing, can identify the molecular genetic basis of the disease in families with limb-girdle muscular dystrophy. The results can be helpful in identifying potential carriers in the family and in prenatal diagnosis to the families involved.


2015 ◽  
Vol 357 ◽  
pp. e339
Author(s):  
V. Mastorodemos ◽  
E. Vogiatzi ◽  
H. Latsoudis ◽  
P. Vorgia ◽  
G. Amoiridis ◽  
...  

2013 ◽  
Vol 58 (8) ◽  
pp. 564-565 ◽  
Author(s):  
Tohru Matsuura ◽  
Tatsuaki Kurosaki ◽  
Yoshio Omote ◽  
Narihiro Minami ◽  
Yukiko K Hayashi ◽  
...  

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 530
Author(s):  
Du Hwan Kim ◽  
Dae-Hyun Jang ◽  
Ja-Hyun Jang

Limb-girdle muscular dystrophy type R2 dysferin-related (LGMD R2 dysferin-related), a phenotype of dysferlinopathy, usually begins with pelvic girdle weakness. A 35-year-old male presented with right leg pain for 2 weeks without a previous history of limb weakness. Magnetic resonance imaging of the lumbar spine showed disc extrusion at L5–S1 and incidental severe fatty degeneration of the lumbar erector spinae. Physical examination demonstrated no definite limb weakness. Serum creatine kinase levels were elevated. Genetic testing using a targeted gene-sequencing panel identified compound heterozygous variants NM_003494.3(DYSF) c.[1284+2T>C]; [5303G>A]. Computed tomography revealed fatty degeneration of lower-limb muscles, which was mild in the adductor muscles and severe in the gluteus minimus. Immunohistochemistry staining of the vastus lateralis showed under-expression of dysferlin. This patient was diagnosed with LGMD R2 dysferin-related. Thus, unusual fatty degeneration of the lumbar paraspinalis can be a manifestation of dysferlinopathy.


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