Browsing by Author "Iwata-Otsubo, Aiko"

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    A 9.8 Mb deletion at 7q31.2q31.31 downstream of FOXP2 in an individual with speech and language impairment suggests a possible positional effect
    (Wiley, 2022-11-19) Iwata-Otsubo, Aiko; Klee, Victoria H.; Ahmad, Aaliya A.; Walsh, Laurence E.; Breman, Amy M.; Medical and Molecular Genetics, School of Medicine
    Haploinsufficiency of FOXP2 causes FOXP2-related speech and language disorder. We report a 9.8 Mb deletion downstream of FOXP2 in a girl with speech and language impairment, developmental delay, and other features. We propose involvement of FOXP2 in pathogenesis of these phenotypes, likely due to positional effects on the gene.
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    A 9.8 Mb deletion at 7q31.2q31.31 downstream of FOXP2 in an individual with speech and language impairment suggests a possible positional effect
    (Wiley, 2022-11-19) Iwata-Otsubo, Aiko; Klee, Victoria H.; Ahmad, Aaliya A.; Walsh, Laurence E.; Breman, Amy M.; Medical and Molecular Genetics, School of Medicine
    Haploinsufficiency of FOXP2 causes FOXP2-related speech and language disorder. We report a 9.8 Mb deletion downstream of FOXP2 in a girl with speech and language impairment, developmental delay, and other features. We propose involvement of FOXP2 in pathogenesis of these phenotypes, likely due to positional effects on the gene.
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    A brother and sister with the same karyotype: Case report of two siblings with partial 3p duplication and partial 9p deletion and sex reversal
    (Wiley, 2021-05-06) Selby, Susan Cordes; Iwata-Otsubo, Aiko; Delk, Paula; Nebesio, Todd D.; Gohil, Anisha; Matlock, Peggy; Torres-Martinez, Wilfredo; Vance, Gail H.; Medical and Molecular Genetics, School of Medicine
    Two siblings with the same male unbalanced karyotype demonstrate sex reversal. The older sib appeared phenotypically female and the younger sib demonstrated a male gender. The female had gonadal dysgenesis with bilateral ovatestes. The male had bilateral testes. The report discusses the phenotypical differences and genes associated with sex reversal.
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    Characterization of Reference Materials for Spinal Muscular Atrophy Genetic Testing: A Genetic Testing Reference Materials Coordination Program Collaborative Project
    (Elsevier, 2021) Prior, Thomas W.; Bayrak-Toydemir, Pinar; Lynnes, Ty C.; Mao, Rong; Metcalf, James D.; Muralidharan, Kasinathan; Iwata-Otsubo, Aiko; Pham, Ha T.; Pratt, Victoria M.; Qureshi, Shumaila; Requesens, Deborah; Shen, Junqing; Vetrini, Francesco; Kalman, Lisa; Medicine, School of Medicine
    Spinal muscular atrophy (SMA) is an autosomal recessive disorder predominately caused by bi-allelic loss of the SMN1 gene. Increased copies of SMN2, a low functioning nearly identical paralog, are associated with a less severe phenotype. SMA was recently recommended for inclusion in newborn screening. Clinical laboratories must accurately measure SMN1 and SMN2 copy number to identify SMA patients and carriers, and to identify individuals likely to benefit from therapeutic interventions. Having publicly available and appropriately characterized reference materials with various combinations of SMN1 and SMN2 copy number variants is critical to assure accurate SMA clinical testing. To address this need, the CDC-based Genetic Testing Reference Materials Coordination Program, in collaboration with members of the genetic testing community and the Coriell Institute for Medical Research, has characterized 15 SMA reference materials derived from publicly available cell lines. DNA samples were distributed to four volunteer testing laboratories for genotyping using three different methods. The characterized samples had zero to four copies of SMN1 and zero to five copies SMN2. The samples also contained clinically important allele combinations (eg, zero copies SMN1, three copies SMN2), and several had markers indicative of an SMA carrier. These and other reference materials characterized by the Genetic Testing Reference Materials Coordination Program are available from the Coriell Institute and are proposed to support the quality of clinical laboratory testing.
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    Epigenetic, genetic, and maternal effects enable stable centromere inheritance
    (Springer, 2022-05-09) Das, Arunika; Iwata-Otsubo, Aiko; Destouni, Aspasia; Dawicki-McKenna, Jennine M.; Boese, Katelyn G.; Black, Ben E.; Lampson, Michael A.; Medical and Molecular Genetics, School of Medicine
    Centromeres are defined epigenetically by the histone H3 variant, CENP-A. The propagation cycle by which preexisting CENP-A nucleosomes serve as templates for nascent assembly predicts epigenetic memory of weakened centromeres. Using a mouse model with reduced levels of CENP-A nucleosomes, we find that an embryonic plastic phase precedes epigenetic memory through development. During this phase, nascent CENP-A nucleosome assembly depends on the maternal Cenpa genotype rather than the preexisting template. Weakened centromeres are thus limited to a single generation, and parental epigenetic differences are eliminated by equal assembly on maternal and paternal centromeres. These differences persist, however, when the underlying DNA of parental centromeres differs in repeat abundance, as assembly during the plastic phase also depends on sufficient repetitive centromere DNA. With contributions of centromere DNA and Cenpa maternal effect, we propose that centromere inheritance naturally minimizes fitness costs associated with weakened centromeres or epigenetic differences between parents.
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    Heterozygous loss-of-function SMC3 variants are associated with variable and incompletely penetrant growth and developmental features
    (medRxiv, 2023-09-28) Ansari, Morad; Faour, Kamli N. W.; Shimamura, Akiko; Grimes, Graeme; Kao, Emeline M.; Denhoff, Erica R.; Blatnik, Ana; Ben-Isvy, Daniel; Wang, Lily; Helm, Benjamin M.; Firth, Helen; Breman, Amy M.; Bijlsma, Emilia K.; Iwata-Otsubo, Aiko; de Ravel, Thomy J. L.; Fusaro, Vincent; Fryer, Alan; Nykamp, Keith; Stühn, Lara G.; Haack, Tobias B.; Korenke, G. Christoph; Constantinou, Panayiotis; Bujakowska, Kinga M.; Low, Karen J.; Place, Emily; Humberson, Jennifer; Napier, Melanie P.; Hoffman, Jessica; Juusola, Jane; Deardorff, Matthew A.; Shao, Wanqing; Rockowitz, Shira; Krantz, Ian; Kaur, Maninder; Raible, Sarah; Kliesch, Sabine; Singer-Berk, Moriel; Groopman, Emily; DiTroia, Stephanie; Ballal, Sonia; Srivastava, Siddharth; Rothfelder, Kathrin; Biskup, Saskia; Rzasa, Jessica; Kerkhof, Jennifer; McConkey, Haley; O'Donnell-Luria, Anne; Sadikovic, Bekim; Hilton, Sarah; Banka, Siddharth; Tüttelmann, Frank; Conrad, Donald; Talkowski, Michael E.; FitzPatrick, David R.; Boone, Philip M.; Medical and Molecular Genetics, School of Medicine
    Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 13 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated a milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, some instead having intriguing symptomatologies with rational biological links to SMC3 including bone marrow failure, acute myeloid leukemia, and Coats retinal vasculopathy. Analyses of transcriptomic and epigenetic data suggest that SMC3 pLoF variants reduce SMC3 expression but do not result in a blood DNA methylation signature clustering with that of CdLS, and that the global transcriptional signature of SMC3 loss is model-dependent. Our finding of substantial population-scale LoF intolerance in concert with variable penetrance in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multi-layered genomic data paired with careful phenotyping.
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    Heterozygous loss-of-function SMC3 variants are associated with variable growth and developmental features
    (Elsevier, 2024) Ansari, Morad; Faour, Kamli N. W.; Shimamura, Akiko; Grimes, Graeme; Kao, Emeline M.; Denhoff, Erica R.; Blatnik, Ana; Ben-Isvy, Daniel; Wang, Lily; Helm, Benjamin M.; Firth, Helen; Breman, Amy M.; Bijlsma, Emilia K.; Iwata-Otsubo, Aiko; de Ravel, Thomy J. L.; Fusaro, Vincent; Fryer, Alan; Nykamp, Keith; Stühn, Lara G.; Haack, Tobias B.; Korenke, G. Christoph; Constantinou, Panayiotis; Bujakowska, Kinga M.; Low, Karen J.; Place, Emily; Humberson, Jennifer; Napier, Melanie P.; Hoffman, Jessica; Juusola, Jane; Deardorff, Matthew A.; Shao, Wanqing; Rockowitz, Shira; Krantz, Ian; Kaur, Maninder; Raible, Sarah; Dortenzio, Victoria; Kliesch, Sabine; Singer-Berk, Moriel; Groopman, Emily; DiTroia, Stephanie; Ballal, Sonia; Srivastava, Siddharth; Rothfelder, Kathrin; Biskup, Saskia; Rzasa, Jessica; Kerkhof, Jennifer; McConkey, Haley; Sadikovic, Bekim; Hilton, Sarah; Banka, Siddharth; Tüttelmann, Frank; Conrad, Donald F.; O'Donnell-Luria, Anne; Talkowski, Michael E.; FitzPatrick, David R.; Boone, Philip M.; Medical and Molecular Genetics, School of Medicine
    Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 14 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism, reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated an overall milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, and some had alternative symptomatologies with rational biological links to SMC3. Analyses of tumor and model system transcriptomic data and epigenetic data in a subset of cases suggest that SMC3 pLoF variants reduce SMC3 expression but do not strongly support clustering with functional genomic signatures of typical CdLS. Our finding of substantial population-scale LoF intolerance in concert with variable growth and developmental features in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multilayered genomic data paired with careful phenotyping.
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    Tracheal Aspirate as an Alternative Biologic Sample for Pharmacogenomics Testing in Mechanically Ventilated Pediatric Patients
    (Wiley, 2021-03) Hargreaves, Katherine A.; Pratt, Victoria M.; Medeiros, Elizabeth B.; Lynnes, Ty C.; Granfield, Caitlin A.; Skaar, Todd C.; Iwata-Otsubo, Aiko; Tillman, Emma M.; Medical and Molecular Genetics, School of Medicine
    Patients in the pediatric intensive care unit are exposed to multiple medications and are at high risk for adverse drug reactions. Pharmacogenomic (PGx) testing could help decrease their risk of adverse reactions. Although whole blood is preferred for PGx testing, blood volume in this population is often limited. However, for patients on mechanical ventilation, tracheal secretions are abundant, frequently suctioned, and discarded. Thus, the aim of this pilot study was to determine if tracheal aspirates could be used as a source of human genomic DNA for PGx testing. We successfully extracted DNA from tracheal secretions of all 23 patients in the study. The samples were successfully genotyped for 10 clinically actionable single nucleotide variants across 3 cytochrome P450 genes (CYP2D6, CYP2C19, and CYP3A5). Using DNA from whole blood samples in 11 of the patients, we confirmed the accuracy of the genotyping with 100% concordance. Therefore, our results support the use of tracheal aspirates from mechanically ventilated children as an adequate biospecimen for clinical genetic testing.