Ataxia and oculomotor apraxia caused by a large-scale deletion in the senataxin gene.

Senataxin, an RNA/DNA helicase, is a key protein providing genome stability and one of the best characterized R-loop-binding factors playing an important role in transcription and DNA repair processes. Pathogenic SETX gene variants cause autosomal recessive spinocerebellar ataxia with axonal neuropathy (AOA2, MIM #606002) and autosomal dominant juvenile amyotrophic lateral sclerosis (ALS4, MIM #602433), rare neurodegenerative disorders characterized by juvenile onset of progressive cerebellar ataxia, axonal sensorimotor peripheral neuropathy, combined upper and lower motor neuron symptoms, and increased serum alpha-fetoprotein (AFP; specific for AOA2). We report two cases of adult patients presenting with cerebellar syndrome, scanned speech, and exercise intolerance which started in the second/third decade of life and were followed by muscle weakness and impaired gait coordination.

Highly Variable Expressivity of a CNV Deletion Involving TBX4 in Three Deceased Siblings With Lung Developmental Disorder and Their Mildly Affected Mother and Grandfather.

Single nucleotide variants (SNVs) and copy-number variant (CNV) deletions involving TBX4 have been associated with pulmonary arterial hypertension, ischiocoxopodopatellar syndrome, and lethal lung developmental disorders (LLDDs). Thus far, all large CNV deletions encompassing entire TBX4 have been found to have arisen de novo. Here, we present a three-generation family with three neonate siblings who died within 35-66 days due to histopathologically diagnosed LLDD.

Molecular analysis of inherited disorders of cornification in polish patients show novel variants and functional data and provokes questions on the significance of secondary findings.

Background: The Mendelian Disorders of Cornification (MeDOC) comprise a large number of disorders that present with either localised (palmoplantar keratoderma, PPK) or generalised (ichthyoses) signs. The MeDOC are highly heterogenic in terms of genetics and phenotype. Consequently, diagnostic process is challenging and before implementation of the next generation sequencing, was mostly symptomatic, not causal, which limited research on those diseases.

HMZDupFinder: a robust computational approach for detecting intragenic homozygous duplications from exome sequencing data.

Homozygous duplications contribute to genetic disease by altering gene dosage or disrupting gene regulation and can be more deleterious to organismal biology than heterozygous duplications. Intragenic exonic duplications can result in loss-of-function (LoF) or gain-of-function (GoF) alleles that when homozygosed, i.e.

Diminished 100 Expression in a Newborn With Acinar Dysplasia and a Novel Variant: A Case Report.

Acinar dysplasia (AcDys) of the lung is a rare lethal developmental disorder in neonates characterized by severe respiratory failure and pulmonary arterial hypertension refractory to treatment. Recently, abnormalities of TBX4-FGF10-FGFR2-TMEM100 signaling regulating lung development have been reported in patients with AcDys due to heterozygous single-nucleotide variants or copy-number variant deletions involving , , or . Here, we describe a female neonate who died at 4 hours of life due to severe respiratory distress related to AcDys diagnosed by postmortem histopathologic evaluation.

SNV/indel hypermutator phenotype in biallelic RAD51C variant: Fanconi anemia.

We previously reported a fetus with Fanconi anemia (FA), complementation group O due to compound heterozygous variants involving RAD51C. Interestingly, the trio exome sequencing analysis also detected eight apparent de novo mosaic variants with variant allele fraction (VAF) ranging between 11.5 and 37%.

Coexisting Conditions Modifying Phenotypes of Patients with 22q11.2 Deletion Syndrome.

22q11.2 deletion syndrome (22q11.2DS) is the most common genomic disorder with an extremely broad phenotypic spectrum.

SNV/indel hypermutator phenotype in biallelic RAD51C variant - Fanconi anemia.

We previously reported a fetus with Fanconi anemia (FA), complementation group O due to compound heterozygous variants involving . Interestingly, the trio exome sequencing analysis also detected eight apparent de novo mosaic variants with variant allele fraction (VAF) ranging between 11.5%-37%.

Cloud-native distributed genomic pileup operations.

Motivation: Pileup analysis is a building block of many bioinformatics pipelines, including variant calling and genotyping. This step tends to become a bottleneck of the entire assay since the straightforward pileup implementations involve processing of all base calls from all alignments sequentially. On the other hand, a distributed version of the algorithm faces the intrinsic challenge of splitting reads-oriented file formats into self-contained partitions to avoid costly data exchange between computational nodes.

High-level gonosomal mosaicism for a pathogenic non-coding CNV deletion of the lung-specific FOXF1 enhancer in an unaffected mother of an infant with ACDMPV.

Background: Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) results from haploinsufficiency of the mesenchymal transcription factor FOXF1 gene. To date, only one case of an ACDMPV-causative CNV deletion inherited from a very-low level somatic mosaic mother has been reported.

Methods: Clinical, histopathological, and molecular studies, including whole genome sequencing, chromosomal microarray analysis, qPCR, and Sanger sequencing, followed by in vitro fertilization (IVF) with preimplantation genetic testing (PGT) were used to study a family with a deceased neonate with ACDMPV.

Variable expressivity in a four-generation ACDMPV family with a non-coding hypermorphic SNV in trans to the frameshifting FOXF1 variant.

Heterozygous single nucleotide variants (SNVs) or copy-number variant deletions involving FOXF1 or its distant lung-specific enhancer on chromosome 16q24.1 have been identified in 80-90% of patients with Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV), a lethal neonatal lung developmental disorder. We describe a four-generation family with a deceased ACDMPV neonate, her sibling from the electively terminated pregnancy, healthy mother with a history of pulmonary arterial hypertension (PAH), an unaffected aunt, an aunt deceased due to findings consistent with ACDMPV, and a reportedly unaffected grandmother, all with the frameshifting variant c.

Loss-of-function variant in chymotrypsin like elastase 3B (CELA3B) is associated with non-alcoholic chronic pancreatitis.

Background: Genetic alterations in digestive enzymes have been associated with chronic pancreatitis (CP). Recently, chymotrypsin like elastase 3B (CELA3B) emerged as a novel risk gene. Thus, we evaluated CELA3B in two European cohorts with CP.

Postzygotic mutations and where to find them - Recent advances and future implications in the field of non-neoplastic somatic mosaicism.

The technological progress of massively parallel sequencing (MPS) has triggered a remarkable development in the research on postzygotic mutations. Although the overwhelming majority of studies in the field focus on oncogenesis, non-neoplastic diseases are attracting more and more attention. The aim of this review was to summarize some of the most recent findings in the field of somatic mosaicism in diseases other than neoplastic events.

The Thousand Polish Genomes-A Database of Polish Variant Allele Frequencies.

Although Slavic populations account for over 4.5% of world inhabitants, no centralised, open-source reference database of genetic variation of any Slavic population exists to date. Such data are crucial for clinical genetics, biomedical research, as well as archeological and historical studies.

Do paternal deletions involving the FOXF1 locus on chromosome 16q24.1 manifest with more severe non-lung anomalies?

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a rare lethal lung developmental disorder in neonates due to heterozygous loss-of-function of the mesenchymal transcription factor gene, FOXF1. Interestingly, unlike ACDMPV-causing point mutations in FOXF1 that can be inherited from the mother or father, causative copy-number variant (CNV) deletions arise de novo and almost exclusively on chromosome 16 inherited from the mother (n = 50 vs. n = 3).

Exacerbation of mild lung disorders to lethal pulmonary hypoplasia by a noncoding hypomorphic SNV in a lung-specific enhancer in trans to the frameshifting TBX4 variant.

Variants involving TBX4 are associated with a wide variety of disorders, including pulmonary arterial hypertension, ischiocoxopodopatellar syndrome (ICPPS)/small patella syndrome (SPS), lethal lung developmental disorders (LLDDs) in neonates, heart defects, and prenatally lethal posterior amelia with pelvic and pulmonary hypoplasia syndrome. The objective of our study was to elucidate the wide variable phenotypic expressivity and incomplete penetrance in a three-generation family with a truncating variant in TBX4. In addition to exome and genome sequencing analyses, a candidate noncoding regulatory single nucleotide variant (SNV) within the lung-specific TBX4 enhancer was functionally tested using an in vitro luciferase reporter assay.

Exome Sequencing Reveals Novel Variants and Expands the Genetic Landscape for Congenital Microcephaly.

Congenital microcephaly causes smaller than average head circumference relative to age, sex and ethnicity and is most usually associated with a variety of neurodevelopmental disorders. The underlying etiology is highly heterogeneous and can be either environmental or genetic. Disruption of any one of multiple biological processes, such as those underlying neurogenesis, cell cycle and division, DNA repair or transcription regulation, can result in microcephaly.

Detection of low-level parental somatic mosaicism for clinically relevant SNVs and indels identified in a large exome sequencing dataset.

Background: Due to the limitations of the current routine diagnostic methods, low-level somatic mosaicism with variant allele fraction (VAF) < 10% is often undetected in clinical settings. To date, only a few studies have attempted to analyze tissue distribution of low-level parental mosaicism in a large clinical exome sequencing (ES) cohort.

Methods: Using a customized bioinformatics pipeline, we analyzed apparent de novo single-nucleotide variants or indels identified in the affected probands in ES trio data at Baylor Genetics clinical laboratories.

Wide Fontanels, Delayed Speech Development and Hoarse Voice as Useful Signs in the Diagnosis of KBG Syndrome: A Clinical Description of 23 Cases with Pathogenic Variants Involving the Gene or Submicroscopic Chromosomal Rearrangements of 16q24.3.

KBG syndrome is a neurodevelopmental autosomal dominant disorder characterized by short stature, macrodontia, developmental delay, behavioral problems, speech delay and delayed closing of fontanels. Most patients with KBG syndrome are found to have a mutation in the gene or a chromosomal rearrangement involving this gene. We hereby present clinical evaluations of 23 patients aged 4 months to 26 years manifesting clinical features of KBG syndrome.