scholarly journals Parental Somatic Mosaicism Uncovers Inheritance of an Apparently De Novo GFAP Mutation

2021 ◽  
Vol 12 ◽  
Author(s):  
Alice Grossi ◽  
Federico Morelli ◽  
Marco Di Duca ◽  
Francesco Caroli ◽  
Isabella Moroni ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Mutant Allele ◽  
De Novo ◽  
Somatic Mosaicism ◽  
Alexander Disease ◽  
Germline Mosaicism ◽  
Affected Sibling ◽  
Next Generation Sequencing Ngs ◽  
Germinal Mosaicism ◽  
Generation Sequencing

Alexander disease is a leukodystrophy caused by heterozygous mutations of GFAP gene. Recurrence in siblings from healthy parents provides a confirmation to the transmission of variants through germinal mosaicism. With the use of DNA isolated from peripheral blood, next-generation sequencing (NGS) of GFAP locus was performed with deep coverage (≥500×) in 11 probands and their parents (trios) with probands heterozygous for apparently de novo GFAP mutations. Indeed, one parent had somatic mosaicism, estimated in the range of 8.9%–16%, for the mutant allele transmitted to the affected sibling. Parental germline mosaicism deserves attention, as it is critical in assessing the risk of recurrence in families with Alexander disease.

Zellfreie fetale DNA im mütterlichen Blut: neue Möglichkeiten in der pränatalen Diagnostik/Cell free fetal DNA in maternal blood: new possibilities in prenatal diagnosis

2012 ◽  
Vol 36 (5) ◽  
Author(s):  
Markus Stumm ◽  
Rolf-Dieter Wegner ◽  
Wera Hofmann
Keyword(s):  
Prenatal Diagnosis ◽  
Next Generation Sequencing ◽  
De Novo ◽  
Maternal Blood ◽  
Fetal Dna ◽  
Cell Free Fetal Dna ◽  
Next Generation Sequencing Ngs ◽  
Fetale Dna ◽  
Generation Sequencing ◽  
Zellfreie Fetale Dna

ZusammenfassungDie zellfreie fetale DNA (cff-DNA) im mütterlichen Blut bietet viele neue Möglichkeiten der pränatalen genetischen Diagnostik. Im Gegensatz zu den etablierten invasiven Techniken der Chorionzottenbiopsie (CVS) und der Amniozentese (AC), die beide mit einem spezifischen Risiko (0,5–1%) einer eingriffsbedingten Fehlgeburt einhergehen, ist die Grundlage für die Gewinnung der cff-DNA eine einfache venöse Blutentnahme der Mutter, die keinerlei Risiko für den Embryo oder Feten darstellt. Damit bietet die cff-DNA die Möglichkeit einer risikofreien genetischen Diagnostik von bestehenden Schwangerschaften. Molekulargenetische Techniken werden schon seit längerer Zeit zum qualitativen Nachweis von spezifischen fetalen Sequenzen, wie paternal vererbten oder neu entstandenen (de novo) Mutationen, eingesetzt. Durch den Einsatz digitaler PCR und Next-Generation-Sequencing (NGS) Technologien gelingt mittlerweile aber auch der sichere quantitative Nachweis von mutierten Allelen sowie von klinisch relevanten Aneuploidien (Trisomie 13, 18 und 21) aus fetaler DNA im mütterlichen Blut.

scholarly journals De Novo Assembly-Based Analysis of RPGR Exon ORF15 in an Indigenous African Cohort Overcomes Limitations of a Standard Next-Generation Sequencing (NGS) Data Analysis Pipeline

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 800
Author(s):  
Jordi Maggi ◽  
Lisa Roberts ◽  
Samuel Koller ◽  
George Rebello ◽  
Wolfgang Berger ◽  
...  
Keyword(s):  
Data Analysis ◽  
Next Generation Sequencing ◽  
De Novo Assembly ◽  
De Novo ◽  
African Ancestry ◽  
Secondary Analysis ◽  
Next Generation ◽  
Analysis Pipeline ◽  
Next Generation Sequencing Ngs ◽  
Generation Sequencing

RPGR exon ORF15 variants are one of the most frequent causes for inherited retinal disorders (IRDs), in particular retinitis pigmentosa. The low sequence complexity of this mutation hotspot makes it prone to indels and challenging for sequence data analysis. Whole-exome sequencing generally fails to provide adequate coverage in this region. Therefore, complementary methods are needed to avoid false positives as well as negative results. In this study, next-generation sequencing (NGS) was used to sequence long-range PCR amplicons for an IRD cohort of African ancestry. By developing a novel secondary analysis pipeline based on de novo assembly, we were able to avoid the miscalling of variants generated by standard NGS analysis tools. We identified pathogenic variants in 11 patients (13% of the cohort), two of which have not been reported previously. We provide a novel and alternative end-to-end secondary analysis pipeline for targeted NGS of ORF15 that is less prone to false positive and negative variant calls.

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