Somatic mosaicism of a heterogeneous mutation of ACTA 1 in nemaline myopathy

2019 ◽  
Vol 61 (11) ◽  
pp. 1169-1171
Author(s):  
Takayuki Yokoi ◽  
Kenshi Sei ◽  
Yumi Enomoto ◽  
Takuya Naruto ◽  
Kenji Kurosawa
Keyword(s):  
Somatic Mosaicism ◽  
Nemaline Myopathy

Deep sequencing detects very-low-grade somatic mosaicism in the unaffected mother of siblings with nemaline myopathy

2014 ◽  
Vol 24 (7) ◽  
pp. 642-647 ◽  
Author(s):  
Satoko Miyatake ◽  
Eriko Koshimizu ◽  
Yukiko K. Hayashi ◽  
Kazushi Miya ◽  
Masaaki Shiina ◽  
...  
Keyword(s):  
Deep Sequencing ◽  
Somatic Mosaicism ◽  
Nemaline Myopathy ◽  
Low Grade

scholarly journals Phenocopy of a heterozygous carrier of X-linked retinitis pigmentosa due to mosaicism for a RHO variant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ine Strubbe ◽  
Caroline Van Cauwenbergh ◽  
Julie De Zaeytijd ◽  
Sarah De Jaegere ◽  
Marieke De Bruyne ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Somatic Mosaicism ◽  
Retinal Disease ◽  
Hair Follicles ◽  
Disease Genes ◽  
Female Carrier ◽  
Autofluorescence Imaging ◽  
Targeted Next Generation Sequencing ◽  
Whole Exome ◽  
Next Generation Sequencing Ngs

AbstractWe describe both phenotype and pathogenesis in two male siblings with typical retinitis pigmentosa (RP) and the potentially X-linked RP (XLRP) carrier phenotype in their mother. Two affected sons, two unaffected daughters, and their mother underwent detailed ophthalmological assessments including Goldmann perimetry, color vision testing, multimodal imaging and ISCEV-standard electroretinography. Genetic testing consisted of targeted next-generation sequencing (NGS) of known XLRP genes and whole exome sequencing (WES) of known inherited retinal disease genes (RetNet-WES). Variant validation and segregation analysis were performed by Sanger sequencing. The mutational load of the RHO variant in the mother was assessed in DNA from leucocytes, buccal cells and hair follicles using targeted NGS. Both affected sons showed signs of classical RP, while the mother displayed patches of hyperautofluorescence on blue light autofluorescence imaging and regional, intraretinal, spicular pigmentation, reminiscent of a carrier phenotype of XLRP. XLRP testing was negative. RetNet-WES testing revealed RHO variant c.404G > C p.(Arg135Pro) in a mosaic state (21% of the reads) in the mother and in a heterozygous state in both sons. Targeted NGQSS of the RHO variant in different maternal tissues showed a mutation load between 25.06% and 41.72%. We report for the first time that somatic mosaicism of RHO variant c.404G > C p.(Arg135Pro) mimics the phenotype of a female carrier of XLRP, in combination with heterozygosity for the variant in the two affected sons.

scholarly journals De novo TRPV4 Leu619Pro variant causes a new channelopathy characterised by giant cell lesions of the jaws and skull, skeletal abnormalities and polyneuropathy

2021 ◽  
pp. jmedgenet-2020-107427
Author(s):  
Aviel Ragamin ◽  
Carolina C Gomes ◽  
Karen Bindels-de Heus ◽  
Renata Sandoval ◽  
Angelia V Bassenden ◽  
...  
Keyword(s):  
Giant Cell ◽  
De Novo ◽  
Neuromuscular Disorders ◽  
Somatic Mosaicism ◽  
Ion Leakage ◽  
Gain Of Function ◽  
Therapeutic Modalities ◽  
Organ Systems ◽  
Heterozygous Variant ◽  
Systemic Disorder

BackgroundPathogenic germline variants in Transient Receptor Potential Vanilloid 4 Cation Channel (TRPV4) lead to channelopathies, which are phenotypically diverse and heterogeneous disorders grossly divided in neuromuscular disorders and skeletal dysplasia. We recently reported in sporadic giant cell lesions of the jaws (GCLJs) novel, somatic, heterozygous, gain-of-function mutations in TRPV4, at Met713.MethodsHere we report two unrelated women with a de novo germline p.Leu619Pro TRPV4 variant and an overlapping systemic disorder affecting all organs individually described in TRPV4 channelopathies.ResultsFrom an early age, both patients had several lesions of the nervous system including progressive polyneuropathy, and multiple aggressive giant cell-rich lesions of the jaws and craniofacial/skull bones, and other skeletal lesions. One patient had a relatively milder disease phenotype possibly due to postzygotic somatic mosaicism. Indeed, the TRPV4 p.Leu619Pro variant was present at a lower frequency (variant allele frequency (VAF)=21.6%) than expected for a heterozygous variant as seen in the other proband, and showed variable regional frequency in the GCLJ (VAF ranging from 42% to 10%). In silico structural analysis suggests that the gain-of-function p.Leu619Pro alters the ion channel activity leading to constitutive ion leakage.ConclusionOur findings define a novel polysystemic syndrome due to germline TRPV4 p.Leu619Pro and further extend the spectrum of TRPV4 channelopathies. They further highlight the convergence of TRPV4 mutations on different organ systems leading to complex phenotypes which are further mitigated by possible post-zygotic mosaicism. Treatment of this disorder is challenging, and surgical intervention of the GCLJ worsens the lesions, suggesting the future use of MEK inhibitors and TRPV4 antagonists as therapeutic modalities for unmet clinical needs.

scholarly journals Unsuspected somatic mosaicism for FBN1 gene contributes to Marfan syndrome

2021 ◽  
Author(s):  
Pauline Arnaud ◽  
Hélène Morel ◽  
Olivier Milleron ◽  
Laurent Gouya ◽  
Christine Francannet ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Somatic Mosaicism ◽  
Variant Calling ◽  
Copy Number Variations ◽  
Pathogenic Variant ◽  
Single Nucleotide Variants ◽  
Bioinformatics Analyses ◽  
Single Nucleotide ◽  
Fbn1 Gene ◽  
Pathogenic Variants

Abstract Purpose Individuals with mosaic pathogenic variants in the FBN1 gene are mainly described in the course of familial screening. In the literature, almost all these mosaic individuals are asymptomatic. In this study, we report the experience of our team on more than 5,000 Marfan syndrome (MFS) probands. Methods Next-generation sequencing (NGS) capture technology allowed us to identify five cases of MFS probands who harbored a mosaic pathogenic variant in the FBN1 gene. Results These five sporadic mosaic probands displayed classical features usually seen in Marfan syndrome. Combined with the results of the literature, these rare findings concerned both single-nucleotide variants and copy-number variations. Conclusion This underestimated finding should not be overlooked in the molecular diagnosis of MFS patients and warrants an adaptation of the parameters used in bioinformatics analyses. The five present cases of symptomatic MFS probands harboring a mosaic FBN1 pathogenic variant reinforce the fact that apparently asymptomatic mosaic parents should have a complete clinical examination and a regular cardiovascular follow-up. We advise that individuals with a typical MFS for whom no single-nucleotide pathogenic variant or exon deletion/duplication was identified should be tested by NGS capture panel with an adapted variant calling analysis.

scholarly journals The Maize Unstable factor for orange1 Is a Dominant Epigenetic Modifier of a Tissue Specifically Silent Allele of pericarp color1

Genetics ◽  
2003 ◽  
Vol 163 (3) ◽  
pp. 1135-1146 ◽  
Author(s):  
Surinder Chopra ◽  
Suzy M Cocciolone ◽  
Shaun Bushman ◽  
Vineet Sangar ◽  
Michael D McMullen ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Somatic Mosaicism ◽  
Methylation State ◽  
Vegetative Tissues ◽  
Epigenetic Modifier ◽  
Gene Copies ◽  
Allele Specific ◽  
Silent Allele ◽  
Methylation Patterns ◽  
Variable Penetrance

Abstract We have characterized Unstable factor for orange1 (Ufo1), a dominant, allele-specific modifier of expression of the maize pericarp color1 (p1) gene. The p1 gene encodes an Myb-homologous transcriptional activator of genes required for biosynthesis of red phlobaphene pigments. The P1-wr allele specifies colorless kernel pericarp and red cobs, whereas Ufo1 modifies P1-wr expression to confer pigmentation in kernel pericarp, as well as vegetative tissues, which normally do not accumulate significant amounts of phlobaphene pigments. In the presence of Ufo1, P1-wr transcript levels and transcription rate are increased in kernel pericarp. The P1-wr allele contains approximately six p1 gene copies present in a hypermethylated and multicopy tandem array. In P1-wr Ufo1 plants, methylation of P1-wr DNA sequences is reduced, whereas the methylation state of other repetitive genomic sequences was not detectably affected. The phenotypes produced by the interaction of P1-wr and Ufo1 are unstable, exhibiting somatic mosaicism and variable penetrance. Moreover, the changes in P1-wr expression and methylation are not heritable: meiotic segregants that lack Ufo1 revert to the normal P1-wr expression and methylation patterns. These results demonstrate the existence of a class of modifiers of gene expression whose effects are associated with transient changes in DNA methylation of specific loci.

scholarly journals Cerebrospinal fluid liquid biopsy for detecting somatic mosaicism in brain

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Zimeng Ye ◽  
Zac Chatterton ◽  
Jahnvi Pflueger ◽  
John A Damiano ◽  
Lara McQuillan ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Liquid Biopsy ◽  
Somatic Mutations ◽  
Somatic Mosaicism ◽  
Autism Spectrum ◽  
Brain Diseases ◽  
Cell Free Dna ◽  
Free Dna ◽  
Subcortical Band Heterotopia ◽  
Fluid Cell

Abstract Brain somatic mutations are an increasingly recognized cause of epilepsy, brain malformations and autism spectrum disorders and may be a hidden cause of other neurodevelopmental and neurodegenerative disorders. At present, brain mosaicism can be detected only in the rare situations of autopsy or brain biopsy. Liquid biopsy using cell-free DNA derived from cerebrospinal fluid has detected somatic mutations in malignant brain tumours. Here, we asked if cerebrospinal fluid liquid biopsy can be used to detect somatic mosaicism in non-malignant brain diseases. First, we reliably quantified cerebrospinal fluid cell-free DNA in 28 patients with focal epilepsy and 28 controls using droplet digital PCR. Then, in three patients we identified somatic mutations in cerebrospinal fluid: in one patient with subcortical band heterotopia the LIS1 p. Lys64* variant at 9.4% frequency; in a second patient with focal cortical dysplasia the TSC1 p. Phe581His*6 variant at 7.8% frequency; and in a third patient with ganglioglioma the BRAF p. Val600Glu variant at 3.2% frequency. To determine if cerebrospinal fluid cell-free DNA was brain-derived, whole-genome bisulphite sequencing was performed and brain-specific DNA methylation patterns were found to be significantly enriched (P = 0.03). Our proof of principle study shows that cerebrospinal fluid liquid biopsy is valuable in investigating mosaic neurological disorders where brain tissue is unavailable.

α-Actinin and myosin light chains in congenital nemaline myopathy

1990 ◽  
Vol 6 (3) ◽  
pp. 171-174 ◽  
Author(s):  
Carina Wallgren-Pettersson ◽  
Pirkko Arjomaa ◽  
Christer Holmberg
Keyword(s):  
Nemaline Myopathy ◽  
Light Chains ◽  
Myosin Light Chains

Detection of somatic mosaicism and classification of Fanconi anemia patients by analysis of the FA/BRCA pathway

Blood ◽  
2005 ◽  
Vol 105 (3) ◽  
pp. 1329-1336 ◽  
Author(s):  
Jean Soulier ◽  
Thierry Leblanc ◽  
Jérôme Larghero ◽  
Hélène Dastot ◽  
Akiko Shimamura ◽  
...  
Keyword(s):  
Fanconi Anemia ◽  
Cancer Susceptibility ◽  
Bone Marrow Failure ◽  
Somatic Mosaicism ◽  
Chromosome Breakage ◽  
Peripheral Blood Lymphocytes ◽  
Specific Analysis ◽  
Number Of Patients ◽  
Chromosome Fragility

AbstractFanconi anemia (FA) is characterized by congenital abnormalities, bone marrow failure, chromosome fragility, and cancer susceptibility. Eight FA-associated genes have been identified so far, the products of which function in the FA/BRCA pathway. A key event in the pathway is the monoubiquitination of the FANCD2 protein, which depends on a multiprotein FA core complex. In a number of patients, spontaneous genetic reversion can correct FA mutations, leading to somatic mosaicism. We analyzed the FA/BRCA pathway in 53 FA patients by FANCD2 immunoblots and chromosome breakage tests. Strikingly, FANCD2 monoubiquitination was detected in peripheral blood lymphocytes (PBLs) in 8 (15%) patients. FA reversion was further shown in these patients by comparison of primary fibro-blasts and PBLs. Reversion was associated with higher blood counts and clinical stability or improvement. Once constitutional FANCD2 patterns were determined, patients could be classified based on the level of FA/BRCA pathway disruption, as “FA core” (upstream inactivation; n = 47, 89%), FA-D2 (n = 4, 8%), and an unidentified downstream group (n = 2, 4%). FA-D2 and unidentified group patients were therefore relatively common, and they had more severe congenital phenotypes. These results show that specific analysis of the FA/BRCA pathway, combined with clinical and chromosome breakage data, allows a comprehensive characterization of FA patients.

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