Browsing by Author "Treat, Kayla"

Now showing 1 - 5 of 5
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    Assessing parental understanding of variant reclassification in pediatric neurology and developmental pediatrics clinics
    (Springer, 2021) Margolin, Amy; Helm, Benjamin M.; Treat, Kayla; Prucka, Sandra K.; Halverson, Colin M.E.; Medical and Molecular Genetics, School of Medicine
    Improvements in technology used for genetic testing have yielded an increased numbers of variants that are identified, each with a potential to return uninformative results. While some genetics providers may expect patients to be responsible for staying abreast of updates to their genetic testing results, it is unknown whether patients are even aware of the possibility of variant reclassification. Little research has assessed the comprehension and attitudes of parents of pediatric patients regarding reclassification of variants of uncertain significance (VUS). Semi-structured telephone interviews were conducted with parents (n = 15) whose children received a VUS from genetic testing in either the pediatric neurogenetics or developmental pediatrics clinics at Riley Hospital for Children in Indianapolis, Indiana. Most participants expressed understanding of the uncertainty surrounding their child's VUS test result. However, nearly half of participants shared that they had no prior knowledge of its potential reclassification. When asked whose responsibility it is to keep informed about changes to their child's VUS status, some participants stated that it belonged solely to healthcare providers - a distinctive finding of our study - whereas others felt that it was a joint responsibility between providers and the parents. We additionally found that some patients desire a support group for individuals with VUS. These results provide insight into the importance of pretest genetic counseling and the need for increased social and informational support for parents of children who receive inconclusive genetic testing results. We conclude that relying solely on the patient or guardian to manage uncertain results may be insufficient.
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    BICRA, a SWI/SNF Complex Member, Is Associated with BAF-Disorder Related Phenotypes in Humans and Model Organisms
    (Elsevier, 2020-12-03) Barish, Scott; Barakat, Tahsin Stefan; Michel, Brittany C.; Mashtalir, Nazar; Phillips, Jennifer B.; Valencia, Alfredo M.; Ugur, Berrak; Wegner, Jeremy; Scott, Tiana M.; Bostwick, Brett; Murdock, David R.; Dai, Hongzheng; Perenthaler, Elena; Nikoncuk, Anita; van Slegtenhorst, Marjon; Brooks, Alice S.; Keren, Boris; Nava, Caroline; Mignot, Cyril; Douglas, Jessica; Rodan, Lance; Nowak, Catherine; Ellard, Sian; Stals, Karen; Lynch, Sally Ann; Faoucher, Marie; Lesca, Gaetan; Edery, Patrick; Engleman, Kendra L.; Zhou, Dihong; Thiffault, Isabelle; Herriges, John; Gass, Jennifer; Louie, Raymond J.; Stolerman, Elliot; Washington, Camerun; Vetrini, Francesco; Otsubo, Aiko; Pratt, Victoria M.; Conboy, Erin; Treat, Kayla; Shannon, Nora; Camacho, Jose; Wakeling, Emma; Yuan, Bo; Chen, Chun-An; Rosenfeld, Jill A.; Westerfield, Monte; Wangler, Michael; Yamamoto, Shinya; Kadoch, Cigall; Scott, Daryl A.; Bellen, Hugo J.; Medical and Molecular Genetics, School of Medicine
    SWI/SNF-related intellectual disability disorders (SSRIDDs) are rare neurodevelopmental disorders characterized by developmental disability, coarse facial features, and fifth digit/nail hypoplasia that are caused by pathogenic variants in genes that encode for members of the SWI/SNF (or BAF) family of chromatin remodeling complexes. We have identified 12 individuals with rare variants (10 loss-of-function, 2 missense) in the BICRA (BRD4 interacting chromatin remodeling complex-associated protein) gene, also known as GLTSCR1, which encodes a subunit of the non-canonical BAF (ncBAF) complex. These individuals exhibited neurodevelopmental phenotypes that include developmental delay, intellectual disability, autism spectrum disorder, and behavioral abnormalities as well as dysmorphic features. Notably, the majority of individuals lack the fifth digit/nail hypoplasia phenotype, a hallmark of most SSRIDDs. To confirm the role of BICRA in the development of these phenotypes, we performed functional characterization of the zebrafish and Drosophila orthologs of BICRA. In zebrafish, a mutation of bicra that mimics one of the loss-of-function variants leads to craniofacial defects possibly akin to the dysmorphic facial features seen in individuals harboring putatively pathogenic BICRA variants. We further show that Bicra physically binds to other non-canonical ncBAF complex members, including the BRD9/7 ortholog, CG7154, and is the defining member of the ncBAF complex in flies. Like other SWI/SNF complex members, loss of Bicra function in flies acts as a dominant enhancer of position effect variegation but in a more context-specific manner. We conclude that haploinsufficiency of BICRA leads to a unique SSRIDD in humans whose phenotypes overlap with those previously reported.
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    Characterization of a novel deep-intronic variant in DYNC2H1 identified by whole-exome sequencing in a patient with a lethal form of a short-rib thoracic dysplasia type III
    (Cold Spring Harbor Laboratory, 2022-12-28) Buchh, Muqsit; Gillespie, Patrick J.; Treat, Kayla; Abreu, Marco A.; Schwantes-An, Tae-Hwi Linus; Helm, Benjamin M.; Fang, Fang; Xuei, Xiaoling; Mantcheva, Lili; Suhrie, Kristen R.; Graham, Brett H.; Conboy, Erin; Vetrini, Francesco; Medical and Molecular Genetics, School of Medicine
    Biallelic pathogenic variants in DYNC2H1 are the cause of short-rib thoracic dysplasia type III with or without polydactyly (OMIM #613091), a skeletal ciliopathy characterized by thoracic hypoplasia due to short ribs. In this report, we review the case of a patient who was admitted to the Neonatal Intensive Care Unit (NICU) of Indiana University Health (IUH) for respiratory support after experiencing respiratory distress secondary to a small, narrow chest causing restrictive lung disease. Additional phenotypic features include postaxial polydactyly, short proximal long bones, and ambiguous genitalia were noted. Exome sequencing (ES) revealed a maternally inherited likely pathogenic variant c.10322C > T p.(Leu3448Pro) in the DYNC2H1 gene. However, there was no variant found on the paternal allele. Microarray analysis to detect deletion or duplication in DYNC2H1 was normal. Therefore, there was insufficient evidence to establish a molecular diagnosis. To further explore the data and perform additional investigations, the patient was subsequently enrolled in the Undiagnosed Rare Disease Clinic (URDC) at Indiana University School of Medicine (IUSM). The investigators at the URDC performed a reanalysis of the ES raw data, which revealed a paternally inherited DYNC2H1 deep-intronic variant c.10606-14A > G predicted to create a strong cryptic acceptor splice site. Additionally, the RNA sequencing of fibroblasts demonstrated partial intron retention predicted to cause a premature stop codon and nonsense-mediated mRNA decay (NMD). Droplet digital RT-PCR (RT-ddPCR) showed a drastic reduction by 74% of DYNCH2H1 mRNA levels. As a result, the intronic variant was subsequently reclassified as likely pathogenic resulting in a definitive clinical and genetic diagnosis for this patient. Reanalysis of ES and fibroblast mRNA experiments confirmed the pathogenicity of the splicing variants to supplement critical information not revealed in original ES or CMA reports. The NICU and URDC collaboration ended the diagnostic odyssey for this family; furthermore, its importance is emphasized by the possibility of prenatally diagnosing the mother's current pregnancy.
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    Macrocephaly and developmental delay caused by missense variants in RAB5C
    (Oxford University Press, 2023) Koop, Klaas; Yuan, Weimin; Tessadori, Federico; Rodriguez-Polanco, Wilmer R.; Grubbs, Jeremy; Zhang, Bo; Osmond, Matt; Graham, Gail; Sawyer, Sarah; Conboy, Erin; Vetrini, Francesco; Treat, Kayla; Płoski, Rafal; Pienkowski, Victor Murcia; Kłosowska, Anna; Fieg, Elizabeth; Krier, Joel; Mallebranche, Coralie; Alban, Ziegler; Aldinger, Kimberly A.; Ritter, Deborah; Macnamara, Ellen; Sullivan, Bonnie; Herriges, John; Alaimo, Joseph T.; Helbig, Catherine; Ellis, Colin A.; van Eyk, Clare; Gecz, Jozef; Farrugia, Daniel; Osei-Owusu, Ikeoluwa; Adès, Lesley; van den Boogaard, Marie-Jose; Fuchs, Sabine; Bakker, Jeroen; Duran, Karen; Dawson, Zachary D.; Lindsey, Anika; Huang, Huiyan; Baldridge, Dustin; Silverman, Gary A.; Grant, Barth D.; Raizen, David; Undiagnosed Diseases Network; van Haaften, Gijs; Pak, Stephen C.; Rehmann, Holger; Schedl, Tim; van Hasselt, Peter; Medical and Molecular Genetics, School of Medicine
    Rab GTPases are important regulators of intracellular vesicular trafficking. RAB5C is a member of the Rab GTPase family that plays an important role in the endocytic pathway, membrane protein recycling and signaling. Here we report on 12 individuals with nine different heterozygous de novo variants in RAB5C. All but one patient with missense variants (n = 9) exhibited macrocephaly, combined with mild-to-moderate developmental delay. Patients with loss of function variants (n = 2) had an apparently more severe clinical phenotype with refractory epilepsy and intellectual disability but a normal head circumference. Four missense variants were investigated experimentally. In vitro biochemical studies revealed that all four variants were damaging, resulting in increased nucleotide exchange rate, attenuated responsivity to guanine exchange factors and heterogeneous effects on interactions with effector proteins. Studies in C. elegans confirmed that all four variants were damaging in vivo and showed defects in endocytic pathway function. The variant heterozygotes displayed phenotypes that were not observed in null heterozygotes, with two shown to be through a dominant negative mechanism. Expression of the human RAB5C variants in zebrafish embryos resulted in defective development, further underscoring the damaging effects of the RAB5C variants. Our combined bioinformatic, in vitro and in vivo experimental studies and clinical data support the association of RAB5C missense variants with a neurodevelopmental disorder characterized by macrocephaly and mild-to-moderate developmental delay through disruption of the endocytic pathway.
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    Reanalysis of a novel variant in the IGF1R gene in a family with variable prenatal and postnatal growth retardation and dysmorphic features: benefits and feasibility of IUSM-URDC (Undiagnosed Rare Disease Clinic) program
    (Cold Spring Harbor Laboratory Press, 2022-03-24) Jacobs, Annalise; Burns, Catherine; Patel, Purva; Treat, Kayla; Helm, Benjamin M.; Conboy, Erin; Vetrini, Francesco; Pediatrics, School of Medicine
    IGF1R-related disorders are associated with intrauterine growth restriction (IUGR), postnatal growth failure, short stature, microcephaly, developmental delay, and dysmorphic facial features. We report a patient who presented to medical genetics at 7 mo of age with a history of IUGR, poor feeding, mild developmental delays, microcephaly, and dysmorphic facial features. Whole-exome sequencing revealed a novel c.1464T > G p.(Cys488Trp) variant in the IGF1R gene, initially classified as a variation of uncertain significance (VUS). We enrolled the patient in the URDC (Undiagnosed Rare Disease Clinic) and performed additional studies including deep phenotyping and familial segregation analysis, which demonstrated that the patient's IGF1R VUS was present in phenotypically similar family members. Furthermore, biochemical testing revealed an elevated serum IGF-1 level consistent with abnormal IGF-1 receptor function. Workup resulted in the patient's variant being upgraded from a VUS to likely pathogenic. Our report expands the variant and phenotypic spectrum of IGF1R-related disorders and illustrates benefits and feasibility of reassessing a VUS beyond the initial molecular diagnosis by deep phenotyping, 3D modeling, additional biochemical testing, and familial segregation studies through the URDC, a multidisciplinary clinical program whose major goal is to end the diagnostic odyssey in patients with rare diseases.