@article {348, title = {An Organismal CNV Mutator Phenotype Restricted to Early Human Development.}, journal = {Cell}, volume = {168}, year = {2017}, month = {2017 02 23}, pages = {830-842.e7}, abstract = {

De novo copy number variants (dnCNVs) arising at~multiple loci in a personal genome have usually been considered to reflect cancer somatic genomic instabilities. We describe a multiple dnCNV (MdnCNV) phenomenon in which individuals with genomic disorders carry five to ten constitutional dnCNVs. These CNVs originate from independent formation incidences, are predominantly tandem duplications or complex gains, exhibit breakpoint junction features reminiscent of replicative repair, and show increased de novo point mutations flanking the rearrangement junctions. The active CNV mutation shower appears to be restricted to a transient perizygotic period. We~propose that a defect in the CNV formation process is responsible for the "CNV-mutator state," and this state is dampened after early embryogenesis. The constitutional MdnCNV phenomenon resembles chromosomal instability in various cancers. Investigations of this phenomenon may provide unique access to understanding genomic disorders, structural variant mutagenesis, human evolution, and cancer biology.

}, keywords = {Chromosome Aberrations, Chromosome Breakpoints, Chromosome Duplication, DNA Copy Number Variations, DNA Replication, Embryonic Development, Female, Gametogenesis, Genetic Diseases, Inborn, Genomic Instability, Humans, Male, Mutation}, issn = {1097-4172}, doi = {10.1016/j.cell.2017.01.037}, author = {Liu, Pengfei and Yuan, Bo and Carvalho, Claudia M B and Wuster, Arthur and Walter, Klaudia and Zhang, Ling and Gambin, Tomasz and Chong, Zechen and Campbell, Ian M and Coban Akdemir, Zeynep and Gelowani, Violet and Writzl, Karin and Bacino, Carlos A and Lindsay, Sarah J and Withers, Marjorie and Gonzaga-Jauregui, Claudia and Wiszniewska, Joanna and Scull, Jennifer and Stankiewicz, Pawe{\l} and Jhangiani, Shalini N and Muzny, Donna M and Zhang, Feng and Chen, Ken and Gibbs, Richard A and Rautenstrauss, Bernd and Cheung, Sau Wai and Smith, Janice and Breman, Amy and Shaw, Chad A and Patel, Ankita and Hurles, Matthew E and Lupski, James R} } @article {169, title = {Somatic mosaicism: implications for disease and transmission genetics.}, journal = {Trends Genet}, volume = {31}, year = {2015}, month = {2015 Jul}, pages = {382-92}, abstract = {

Nearly all of the genetic material among cells within an organism is identical. However, single-nucleotide variants (SNVs), small insertions/deletions (indels), copy-number variants (CNVs), and other structural variants (SVs) continually accumulate as cells divide during development. This process results in an organism composed of countless cells, each with its own unique personal genome. Thus, every human is undoubtedly mosaic. Mosaic mutations can go unnoticed, underlie genetic disease or normal human variation, and may be transmitted to the next generation as constitutional variants. We review the influence of the developmental timing of mutations, the mechanisms by which they arise, methods for detecting mosaic variants, and the risk of passing these mutations on to the next generation.

}, keywords = {Animals, Genetic Diseases, Inborn, Genome, Human, Humans, Mosaicism, Mutagenesis, Insertional, Mutation, Polymorphism, Single Nucleotide, Risk, Trinucleotide Repeat Expansion}, issn = {0168-9525}, doi = {10.1016/j.tig.2015.03.013}, author = {Campbell, Ian M and Shaw, Chad A and Stankiewicz, Pawel and Lupski, James R} } @article {229, title = {Parental somatic mosaicism is underrecognized and influences recurrence risk of genomic disorders.}, journal = {Am J Hum Genet}, volume = {95}, year = {2014}, month = {2014 Aug 07}, pages = {173-82}, abstract = {

New human mutations are thought to originate in germ cells, thus making a recurrence of the same mutation in a sibling exceedingly rare. However, increasing sensitivity of genomic technologies has anecdotally revealed mosaicism for mutations in somatic tissues of apparently healthy parents. Such somatically mosaic parents might also have germline mosaicism that can potentially cause unexpected intergenerational recurrences. Here, we show that somatic mosaicism for transmitted mutations among parents of children with simplex genetic disease is more common than currently appreciated. Using the sensitivity of individual-specific breakpoint PCR, we prospectively screened 100 families with children affected by genomic disorders due to rare deletion copy-number variants (CNVs) determined to be de novo by clinical analysis of parental DNA. Surprisingly, we identified four cases of low-level somatic mosaicism for the transmitted CNV in DNA isolated from parental blood. Integrated probabilistic modeling of gametogenesis developed in response to our observations predicts that mutations in parental blood increase recurrence risk substantially more than parental mutations confined to the germline. Moreover, despite the fact that maternally transmitted mutations are the minority of alleles, our model suggests that sexual dimorphisms in gametogenesis result in a greater proportion of somatically mosaic transmitting mothers who are thus at increased risk of recurrence. Therefore, somatic mosaicism together with sexual differences in gametogenesis might explain a considerable fraction of unexpected recurrences of X-linked recessive disease. Overall, our results underscore an important role for somatic mosaicism and mitotic replicative mutational mechanisms in transmission genetics.

}, keywords = {Cell Division, DNA Copy Number Variations, Female, Gametogenesis, Genetic Diseases, Inborn, Genomics, Germ Cells, Germ-Line Mutation, Humans, Male, Models, Genetic, Mosaicism, Mutation, Pedigree, Prospective Studies, Recurrence, Risk, Sex Characteristics, Smith-Magenis Syndrome}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.07.003}, author = {Campbell, Ian M and Yuan, Bo and Robberecht, Caroline and Pfundt, Rolph and Szafranski, Przemyslaw and McEntagart, Meriel E and Nagamani, Sandesh C S and Erez, Ayelet and Bartnik, Magdalena and Wi{\'s}niowiecka-Kowalnik, Barbara and Plunkett, Katie S and Pursley, Amber N and Kang, Sung-Hae L and Bi, Weimin and Lalani, Seema R and Bacino, Carlos A and Vast, Mala and Marks, Karen and Patton, Michael and Olofsson, Peter and Patel, Ankita and Veltman, Joris A and Cheung, Sau Wai and Shaw, Chad A and Vissers, Lisenka E L M and Vermeesch, Joris R and Lupski, James R and Stankiewicz, Pawe{\l}} } @article {287, title = {Mutations in VRK1 associated with complex motor and sensory axonal neuropathy plus microcephaly.}, journal = {JAMA Neurol}, volume = {70}, year = {2013}, month = {2013 Dec}, pages = {1491-8}, abstract = {

IMPORTANCE: Patients with rare diseases and complex clinical presentations represent a challenge for clinical diagnostics. Genomic approaches are allowing the identification of novel variants in genes for very rare disorders, enabling a molecular diagnosis. Genomics is also revealing a phenotypic expansion whereby the full spectrum of clinical expression conveyed by mutant alleles at a locus can be better appreciated.

OBJECTIVE: To elucidate the molecular cause of a complex neuropathy phenotype in 3 patients by applying genomic sequencing strategies.

DESIGN, SETTING, AND PARTICIPANTS: Three affected individuals from 2 unrelated families presented with a complex neuropathy phenotype characterized by axonal sensorimotor neuropathy and microcephaly. They were recruited into the Centers for Mendelian Genomics research program to identify the molecular cause of their phenotype. Whole-genome, targeted whole-exome sequencing, and high-resolution single-nucleotide polymorphism arrays were performed in genetics clinics of tertiary care pediatric hospitals and biomedical research institutions.

MAIN OUTCOMES AND MEASURES: Whole-genome and whole-exome sequencing identified the variants responsible for the patients{\textquoteright} clinical phenotype.

RESULTS: We identified compound heterozygous alleles in 2 affected siblings from 1 family and a homozygous nonsense variant in the third unrelated patient in the vaccinia-related kinase 1 gene (VRK1). In the latter subject, we found a common haplotype on which the nonsense mutation occurred and that segregates in the Ashkenazi Jewish population.

CONCLUSIONS AND RELEVANCE: We report the identification of disease-causing alleles in 3 children from 2 unrelated families with a previously uncharacterized complex axonal motor and sensory neuropathy accompanied by severe nonprogressive microcephaly and cerebral dysgenesis. Our data raise the question of whether VRK1 mutations disturb cell cycle progression and may result in apoptosis of cells in the nervous system. The application of unbiased genomic approaches allows the identification of potentially pathogenic mutations in unsuspected genes in highly genetically heterogeneous and uncharacterized neurological diseases.

}, keywords = {Child, Child, Preschool, DNA Mutational Analysis, Female, Genotype, Hereditary Sensory and Motor Neuropathy, Humans, Infant, Intracellular Signaling Peptides and Proteins, Magnetic Resonance Imaging, Male, Microcephaly, Mutation, Neural Conduction, Polymorphism, Single Nucleotide, Protein-Serine-Threonine Kinases}, issn = {2168-6157}, doi = {10.1001/jamaneurol.2013.4598}, author = {Gonzaga-Jauregui, Claudia and Lotze, Timothy and Jamal, Leila and Penney, Samantha and Campbell, Ian M and Pehlivan, Davut and Hunter, Jill V and Woodbury, Suzanne L and Raymond, Gerald and Adesina, Adekunle M and Jhangiani, Shalini N and Reid, Jeffrey G and Muzny, Donna M and Boerwinkle, Eric and Lupski, James R and Gibbs, Richard A and Wiszniewski, Wojciech} }