scholarly journals Out-of-Frame Mutations in ACTN2 Last Exon Cause a Dominant Distal Myopathy With Facial Weakness

2021 ◽  
Vol 7 (5) ◽  
pp. e619
Author(s):  
Marco Savarese ◽  
Anna Vihola ◽  
Manu E. Jokela ◽  
Sanna Pauliina Huovinen ◽  
Simonetta Gerevini ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Molecular Genetic ◽  
Genetic Diagnosis ◽  
Shoulder Girdle ◽  
Distal Myopathy ◽  
Facial Weakness ◽  
Muscle Mri ◽  
Muscle Involvement ◽  
Molecular Genetic Diagnosis ◽  
Shoulder Girdle Muscles

Background and ObjectivesTo clinically, genetically, and histopathologically characterize patients presenting with an unusual combination of distal myopathy and facial weakness, without involvement of upper limb or shoulder girdle muscles.MethodsTwo families with a novel form of actininopathy were identified. Patients had been followed up over 10 years. Their molecular genetic diagnosis was not clear after extensive investigations, including analysis of candidate genes and FSHD1-related D4Z4 repeats.ResultsPatients shared a similar clinical phenotype and a common pattern of muscle involvement. They presented with a very slowly progressive myopathy involving anterior lower leg and facial muscles. Muscle MRI finding showed complete fat replacement of anterolateral compartment muscles of the lower legs with variable involvement of soleus and gastrocnemius but sparing thigh muscles. Muscle biopsy showed internalized nuclei, myofibrillar disorganization, and rimmed vacuoles. High-throughput sequencing identified in each proband a heterozygous single nucleotide deletion (c.2558del and c.2567del) in the last exon of the ACTN2 gene. The deletions are predicted to lead to a novel but unstructured slightly extended C-terminal amino acid sequence.DiscussionOur findings indicate an unusual form of actininopathy with specific molecular and clinical features. Actininopathy should be considered in the differential diagnosis of distal myopathy combined with facial weakness.

scholarly journals Missense mutations in small muscle protein X-linked (SMPX) cause distal myopathy with protein inclusions

2021 ◽  
Author(s):  
Mridul Johari ◽  
Jaakko Sarparanta ◽  
Anna Vihola ◽  
Per Harald Jonson ◽  
Marco Savarese ◽  
...  
Keyword(s):  
Cell Culture ◽  
High Throughput Sequencing ◽  
Muscle Protein ◽  
Distal Myopathy ◽  
Missense Mutations ◽  
Limb Muscle ◽  
Muscle Involvement ◽  
Culture Studies ◽  
Protein X ◽  
Small Muscle

AbstractUsing deep phenotyping and high-throughput sequencing, we have identified a novel type of distal myopathy caused by mutations in the Small muscle protein X-linked (SMPX) gene. Four different missense mutations were identified in ten patients from nine families in five different countries, suggesting that this disease could be prevalent in other populations as well. Haplotype analysis of patients with similar ancestry revealed two different founder mutations in Southern Europe and France, indicating that the prevalence in these populations may be higher. In our study all patients presented with highly similar clinical features: adult-onset, usually distal more than proximal limb muscle weakness, slowly progressing over decades with preserved walking. Lower limb muscle imaging showed a characteristic pattern of muscle involvement and fatty degeneration. Histopathological and electron microscopic analysis of patient muscle biopsies revealed myopathic findings with rimmed vacuoles and the presence of sarcoplasmic inclusions, some with amyloid-like characteristics. In silico predictions and subsequent cell culture studies showed that the missense mutations increase aggregation propensity of the SMPX protein. In cell culture studies, overexpressed SMPX localized to stress granules and slowed down their clearance.

Clinical and genetic investigation of 136 Japanese patients with congenital hypothyroidism

2020 ◽  
Vol 33 (6) ◽  
pp. 691-701 ◽  
Author(s):  
Tatsushi Tanaka ◽  
Kohei Aoyama ◽  
Atsushi Suzuki ◽  
Shinji Saitoh ◽  
Haruo Mizuno
Keyword(s):  
Congenital Hypothyroidism ◽  
Molecular Genetic ◽  
Genetic Diagnosis ◽  
Japanese Patients ◽  
Thyroid Stimulating Hormone ◽  
Allelic Variant ◽  
Genetic Investigation ◽  
Pathogenic Variants ◽  
Recessive Genes ◽  
Molecular Genetic Diagnosis

AbstractObjectivesCongenital hypothyroidism (CH) is the most common congenital endocrine disorder. Recent advances in genetic testing have revealed its causative mutations in some CH patients. However, the underlying etiology remains unknown in most patients. This study aimed to perform clinical and genetic investigation in Japanese CH patients to uncover genotype-phenotype correlations.MethodsWe enrolled 136 Japanese patients with transient or permanent CH between April 2015 and March 2017, and performed next-generation sequencing of 19 genes implicated in CH.ResultsWe identified potentially pathogenic bi-allelic variants in DUOX2, TSHR, and TPO in 19, 5, and 1 patient, respectively (autosomal recessive), and a potentially pathogenic mono-allelic variant in NKX2-1 (autosomal dominant) in 1 patient. Molecular genetic diagnosis was highly suggested in 26 patients (19%) from 23 families. We also detected a potentially pathogenic mono-allelic variant in five recessive genes (DUOX2, TSHR, TG, DUOXA2, and TPO) in 31 unrelated patients (23%), although the pathogenicity of these variants remains inconclusive. Patients with bi-allelic DUOX2 variants showed a more severe clinical presentation in infancy than those with bi-allelic TSHR variants. However, this trend reversed beyond infancy. There were no statistical differences in initial thyroid stimulating hormone, free thyroxine, thyroglobulin, and levothyroxine dose as of March 2017 between patients with bi-allelic and mono-allelic DUOX2 variants.ConclusionsThe prevalence of potentially-pathogenic variants in Japanese CH patients was similar to that found by previous reports. Our study demonstrates a genotype-phenotype correlation in Japanese CH patients.

Mitochondrial encephalopathies: molecular genetic diagnosis from blood samples

The Lancet ◽  
1991 ◽  
Vol 337 (8753) ◽  
pp. 1311-1313 ◽  
Author(s):  
S.R. Hammans ◽  
M.G. Sweeney ◽  
M. Brockington ◽  
J.A. Morgan-Hughes ◽  
A.E. Harding
Keyword(s):  
Molecular Genetic ◽  
Genetic Diagnosis ◽  
Blood Samples ◽  
Molecular Genetic Diagnosis

scholarly journals Clinician's modern approaches to molecular genetic diagnosis of glioblastomas

2021 ◽  
Vol 67 (1) ◽  
pp. 13-19
Author(s):  
Turna Ashkhatcava ◽  
Marina Tatarinova ◽  
Lali Kogoniya ◽  
David Naskhletashvili ◽  
Vadim Zhukov
Keyword(s):  
Braf Mutation ◽  
Molecular Mechanisms ◽  
Molecular Genetic ◽  
Genetic Diagnosis ◽  
Braf V600e ◽  
Poor Prognostic Factor ◽  
Molecular Genetic Diagnosis ◽  
The Brain ◽  
Tert Mutation ◽  
Primary Glioblastomas

The article is devoted to the issue of molecular genetic diagnosis of cerebral glioblastomas. Despite significant advances in neurooncology, little progress has been made in prolonging the life of patients with cerebral glioblastoma, and a significant part of the effectiveness of treatment depends on the recognition of two prognostic biomarkers: mutations of the isocitrate dehydrogenase (IDH) promoter and  the methylation of the O6-methylguanine methyl transferase (MGMT) promoter. The article summarizes the data of world and domestic clinical studies, allowing to supplement the histological characteristics of primary glioblastomas with genetic markers: the presence of the TERT mutation, EFGR amplification, loss of PTEN function, LOH 10q, and the presence of the BRAF mutation. It should be noted that the amplification of EGFR, causing resistance to apoptotic stimuli and alkylating chemotherapy with Temozolomide, attracts much attention as a therapeutic target. The frequency of occurrence of the TERT mutation is 90% of all tumors of various genesis, most often the TERT mutation is found in oligodendroglioma or primary glioblastoma. Loss of heterozygosity in the region of localization of the PTEN gene is observed in many types of sporadic tumors, including more than 40% of glioblastomas. Mutations in this gene are found in tumors of the brain, endometrium, prostate, kidney, and mammary gland. The presence of a PTEN mutation is a poor prognostic factor. LOH 22q is much more common in secondary glioblastomas (82%) than in primary glioblastomas (41%). Among brain tumors, the BRAF mutation is most common with pleomorphic xanastrocytoma (60-70%).The BRAF V600E mutation was found in epithelioid glioblastoma, which is a rare and aggressive type of glioblastoma, characterized by an unfavorable prognosis (about 6 months) and frequent leptomeningeal spread. Thus, knowledge of the molecular mechanisms of carcinogenesis will enable a personalized approach to treatment with glioblastomas of the brain.

scholarly journals Molecular Genetic Diagnosis of von Hippel-Lindau Disease: Analysis of Five Japanese Families

1996 ◽  
Vol 87 (5) ◽  
pp. 423-428 ◽  
Author(s):  
Hiroshi Kanno ◽  
Taro Shuin ◽  
Keiichi Kondo ◽  
Susumu Ito ◽  
Masahiko Hosaka ◽  
...  
Keyword(s):  
Molecular Genetic ◽  
Genetic Diagnosis ◽  
Von Hippel Lindau ◽  
Von Hippel Lindau Disease ◽  
Molecular Genetic Diagnosis ◽  
Disease Analysis
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