Targeted Next-generation Sequencing Reveals Novel and Rare Variants in Patients With Primary Varicose Veins

AbstractPaediatric cardiomyopathy is a progressive and often lethal disorder and the most common cause of heart failure in children. Despite their severe outcomes, their genetic etiology is still poorly characterised. The current study aimed at uncovering the genetic background of idiopathic primary hypertrophic cardiomyopathy in a cohort of Egyptian children using targeted next-generation sequencing. The study included 24 patients (15 males and 9 females) presented to the cardiomyopathy clinic of Cairo University Children’s Hospital with a median age of 2.75 (0.5–14) years. Consanguinity was positive in 62.5% of patients. A family history of hypertrophic cardiomyopathy was present in 20.8% of patients. Ten rare variants were detected in eight patients; two pathogenic variants (8.3%) in MBPC3 and MYH7, and eight variants of uncertain significance in MYBPC3, TTN, VCL, MYL2, CSRP3, and RBM20.Here, we report on the first national study in Egypt that analysed sarcomeric and non-sarcomeric variants in a cohort of idiopathic paediatric hypertrophic cardiomyopathy patients using next-generation sequencing. The current pilot study suggests that paediatric hypertrophic cardiomyopathy in Egypt might have a particular genetic background, especially with the high burden of consanguinity. Including the genetic testing in the routine diagnostic service is important for a better understanding of the pathophysiology of the disease, proper patient management, and at-risk detection. Genome-wide tests (whole exome/genome sequencing) might be better than the targeted sequencing approach to test primary hypertrophic cardiomyopathy patients in addition to its ability for the identification of novel genetic causes.

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Next-generation Sequencing of RYR1 and CACNA1S in Malignant Hyperthermia and Exertional Heat Illness

Anesthesiology ◽

10.1097/aln.0000000000000610 ◽

2015 ◽

Vol 122 (5) ◽

pp. 1033-1046 ◽

Cited By ~ 39

Author(s):

Dorota Fiszer ◽

Marie-Anne Shaw ◽

Nickla A. Fisher ◽

Ian M. Carr ◽

Pawan K. Gupta ◽

...

Keyword(s):

Next Generation Sequencing ◽

Malignant Hyperthermia ◽

Rare Variants ◽

Heat Illness ◽

General Anesthetics ◽

Next Generation ◽

Targeted Next Generation Sequencing ◽

Variants Of Unknown Significance ◽

Exertional Heat Illness ◽

Generation Sequencing

Abstract Background: Variants in RYR1 are associated with the majority of cases of malignant hyperthermia (MH), a form of heat illness pharmacogenetically triggered by general anesthetics, and they have also been associated with exertional heat illness (EHI). CACNA1S has also been implicated in MH. The authors applied a targeted next-generation sequencing approach to identify variants in RYR1 and CACNA1S in a cohort of unrelated patients diagnosed with MH susceptibility. They also provide the first comprehensive report of sequencing of these two genes in a cohort of survivors of EHI. Methods: DNA extracted from blood was genotyped using a “long” polymerase chain reaction technique, with sequencing on the Illumina GAII® or MiSeq® platforms (Illumina Inc., USA). Variants were assessed for pathogenicity using bioinformatic approaches. For further follow-up, DNA from additional family members and up to 211 MH normal and 556 MH-susceptible unrelated individuals was tested. Results: In 29 MH patients, the authors identified three pathogenic and four novel RYR1 variants, with a further five RYR1 variants previously reported in association with MH. Three novel RYR1 variants were found in the EHI cohort (n = 28) along with two more previously reported in association with MH. Two other variants were reported previously associated with centronuclear myopathy. The authors found one and three rare variants of unknown significance in CACNA1S in the MH and EHI cohorts, respectively. Conclusions: Targeted next-generation sequencing proved efficient at identifying diagnostically useful and potentially implicated variants in RYR1 and CACNA1S in MH and EHI.

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GERMLINE GCM2 MUTATION SCREENING IN CHINESE PRIMARY HYPERPARATHYROIDISM PATIENTS

Endocrine Practice ◽

10.4158/ep-2020-0132 ◽

2020 ◽

Vol 26 (10) ◽

pp. 1093-1104

Author(s):

An Song ◽

Yi Yang ◽

Yabing Wang ◽

Shuzhong Liu ◽

Min Nie ◽

...

Keyword(s):

Next Generation Sequencing ◽

Primary Hyperparathyroidism ◽

Glial Cell ◽

Rare Variants ◽

Mutation Screening ◽

Next Generation ◽

College Hospital ◽

Targeted Next Generation Sequencing ◽

Asian Populations ◽

Generation Sequencing

Objective: Glial cell missing 2 (GCM2), the critical regulator in the development of parathyroid glands, has been associated with the pathogenesis of primary hyperparathyroidism (PHPT). Relevant data in Chinese and other Asian populations are still lacking. This study aimed to screen the germline mutations of GCM2 in Chinese PHPT patients. Methods: A total of 232 patients diagnosed with PHPT at the Peking Union Medical College Hospital from July, 2016, to February, 2019, were screened using targeted next-generation sequencing to identify rare variants of 8 candidate genes associated with PHPT, including GCM2. Luciferase assays were performed to determine the functional impact of the GCM2 variants. Results: Four male patients were found to carry 3 rare missense variants of the GCM2 gene, including c.1162A>G (p.K388E), c.1144G>A (p.V382M), and c.1247A>G (p.Y416C). Two variants (p.K388E and p.V382M) located within a highly conserved region were associated with GCM2 transactivation function. The 2 cases carrying the p.K388E mutation had a pathology of carcinoma, and the case with the p.V382M mutation had atypical adenoma. Conclusion: This study determined an overall GCM2 gain-of-function mutation frequency of 1.3% in a relatively large-sample-sized Chinese PHPT cohort and supported a higher malignant tendency in cases carrying activating GCM2 mutations. Hence, preoperative screening for these GCM2 mutations might be beneficial to treatment decisions, and longer follow-up for such patients is recommended. Abbreviations: aa = amino acid; CASR = calcium-sensing receptor; CCID = C-terminal conserved inhibitory domain; CDC73 = cell division cycle 73; DBD = DNA-binding domain; DNA = deoxyribonucleic acid; FIHP = familial isolated hyperparathyroidism; GCM2 = glial cell missing 2; GBS = GCM-binding site; MEN1 = multiple endocrine neoplasia type 1; NGS = next-generation sequencing; PA = parathyroid adenoma; PCR = polymerase chain reaction; PHPT = primary hyperparathyroidism; PTH = parathyroid hormone; SNV = single nucleotide variant; VUS = variants of uncertain clinical significance

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Yield of Rare Variants Detected by Targeted Next-Generation Sequencing in a Cohort of Romanian Index Patients with Hypertrophic Cardiomyopathy

Diagnostics ◽

10.3390/diagnostics10121061 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1061

Author(s):

Miruna Mihaela Micheu ◽

Nicoleta-Monica Popa-Fotea ◽

Nicoleta Oprescu ◽

Stefan Bogdan ◽

Monica Dan ◽

...

Keyword(s):

Next Generation Sequencing ◽

Hypertrophic Cardiomyopathy ◽

Rare Variants ◽

Causal Variant ◽

Next Generation ◽

Targeted Next Generation Sequencing ◽

Novel Variants ◽

Next Generation Sequencing Ngs ◽

First Time ◽

Generation Sequencing

Background: The aim of this study was to explore the rare variants in a cohort of Romanian index cases with hypertrophic cardiomyopathy (HCM). Methods: Forty-five unrelated probands with HCM were screened by targeted next generation sequencing (NGS) of 47 core and emerging genes connected with HCM. Results: We identified 95 variants with allele frequency < 0.1% in population databases. MYBPC3 and TTN had the largest number of rare variants (17 variants each). A definite genetic etiology was found in 6 probands (13.3%), while inconclusive results due to either known or novel variants were established in 31 cases (68.9%). All disease-causing variants were detected in sarcomeric genes (MYBPC3 and MYH7 with two cases each, and one case in TNNI3 and TPM1 respectively). Multiple variants were detected in 27 subjects (60%), but no proband carried more than one causal variant. Of note, almost half of the rare variants were novel. Conclusions: Herein we reported for the first time the rare variants identified in core and putative genes associated with HCM in a cohort of Romanian unrelated adult patients. The clinical significance of most detected variants is yet to be established, additional studies based on segregation analysis being required for definite classification.

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