@article {918, title = {De novo variants in SNAP25 cause an early-onset developmental and epileptic encephalopathy.}, journal = {Genet Med}, volume = {23}, year = {2021}, month = {2021 04}, pages = {653-660}, abstract = {

PURPOSE: This study aims to provide a comprehensive description of the phenotypic and genotypic spectrum of SNAP25 developmental and epileptic encephalopathy (SNAP25-DEE) by reviewing newly identified and previously reported individuals.

METHODS: Individuals harboring heterozygous missense or loss-of-function variants in SNAP25 were assembled through collaboration with international colleagues, matchmaking platforms, and literature review. For each individual, detailed phenotyping, classification, and structural modeling of the identified variant were performed.

RESULTS: The cohort comprises 23 individuals with pathogenic or likely pathogenic de novo variants in SNAP25. Intellectual disability and early-onset epilepsy were identified as the core symptoms of SNAP25-DEE, with recurrent findings of movement disorders, cerebral visual impairment, and brain atrophy. Structural modeling for all variants predicted possible functional defects concerning SNAP25 or impaired interaction with other components of the SNARE complex.

CONCLUSION: We provide a comprehensive description of SNAP25-DEE with intellectual disability and early-onset epilepsy mostly occurring before the age of two years. These core symptoms and additional recurrent phenotypes show an overlap to genes encoding other components or associated proteins of the SNARE complex such as STX1B, STXBP1, or VAMP2. Thus, these findings advance the concept of a group of neurodevelopmental disorders that may be termed "SNAREopathies."

}, keywords = {Brain Diseases, Child, Preschool, Epilepsy, Humans, Intellectual Disability, Neurodevelopmental Disorders, Phenotype, Synaptosomal-Associated Protein 25}, issn = {1530-0366}, doi = {10.1038/s41436-020-01020-w}, author = {Kl{\"o}ckner, Chiara and Sticht, Heinrich and Zacher, Pia and Popp, Bernt and Babcock, Holly E and Bakker, Dewi P and Barwick, Katy and Bonfert, Michaela V and B{\"o}nnemann, Carsten G and Brilstra, Eva H and Chung, Wendy K and Clarke, Angus J and Devine, Patrick and Donkervoort, Sandra and Fraser, Jamie L and Friedman, Jennifer and Gates, Alyssa and Ghoumid, Jamal and Hobson, Emma and Horvath, Gabriella and Keller-Ramey, Jennifer and Keren, Boris and Kurian, Manju A and Lee, Virgina and Leppig, Kathleen A and Lundgren, Johan and McDonald, Marie T and McLaughlin, Heather M and McTague, Amy and Mefford, Heather C and Mignot, Cyril and Mikati, Mohamad A and Nava, Caroline and Raymond, F Lucy and Sampson, Julian R and Sanchis-Juan, Alba and Shashi, Vandana and Shieh, Joseph T C and Shinawi, Marwan and Slavotinek, Anne and St{\"o}dberg, Tommy and Stong, Nicholas and Sullivan, Jennifer A and Taylor, Ashley C and Toler, Tomi L and van den Boogaard, Marie-Jos{\'e} and van der Crabben, Saskia N and van Gassen, Koen L I and van Jaarsveld, Richard H and Van Ziffle, Jessica and Wadley, Alexandrea F and Wagner, Matias and Wigby, Kristen and Wortmann, Saskia B and Zarate, Yuri A and M{\o}ller, Rikke S and Lemke, Johannes R and Platzer, Konrad} } @article {1010, title = {De novo variants in TCF7L2 are associated with a syndromic neurodevelopmental disorder.}, journal = {Am J Med Genet A}, year = {2021}, month = {2021 May 18}, abstract = {

TCF7L2 encodes transcription factor 7-like 2 (OMIM 602228), a key mediator of the evolutionary conserved canonical Wnt signaling pathway. Although several large-scale sequencing studies have implicated TCF7L2 in intellectual disability and autism, both the genetic mechanism and clinical phenotype have remained incompletely characterized. We present here a comprehensive genetic and phenotypic description of 11 individuals who have been identified to carry de novo variants in TCF7L2, both truncating and missense. Missense variation is clustered in or near a high mobility group box domain, involving this region in these variants{\textquoteright} pathogenicity. All affected individuals present with developmental delays in childhood, but most ultimately achieved normal intelligence or had only mild intellectual disability. Myopia was present in approximately half of the individuals, and some individuals also possessed dysmorphic craniofacial features, orthopedic abnormalities, or neuropsychiatric comorbidities including autism and attention-deficit/hyperactivity disorder (ADHD). We thus present an initial clinical and genotypic spectrum associated with variation in TCF7L2, which will be important in informing both medical management and future research.

}, issn = {1552-4833}, doi = {10.1002/ajmg.a.62254}, author = {Dias, Caroline and Pfundt, Rolph and Kleefstra, Tjitske and Shuurs-Hoeijmakers, Janneke and Boon, Elles M J and van Hagen, Johanna M and Zwijnenburg, Petra and Weiss, Marjan M and Keren, Boris and Mignot, Cyril and Isapof, Arnaud and Weiss, Karin and Hershkovitz, Tova and Iascone, Maria and Maitz, Silvia and Feichtinger, Ren{\'e} G and Kotzot, Dieter and Mayr, Johannes A and Ben-Omran, Tawfeg and Mahmoud, Laila and Pais, Lynn S and Walsh, Christopher A and Shashi, Vandana and Sullivan, Jennifer A and Stong, Nicholas and Lecoquierre, Francois and Guerrot, Anne-Marie and Charollais, Aude and Rodan, Lance H} } @article {810, title = {Missed diagnoses: Clinically relevant lessons learned through medical mysteries solved by the Undiagnosed Diseases Network.}, journal = {Mol Genet Genomic Med}, volume = {8}, year = {2020}, month = {2020 10}, pages = {e1397}, abstract = {

BACKGROUND: Resources within the Undiagnosed Diseases Network (UDN), such as genome sequencing (GS) and model organisms aid in diagnosis and identification of new disease genes, but are currently difficult to access by clinical providers. While these resources do contribute to diagnoses in many cases, they are not always necessary to reach diagnostic resolution. The UDN experience has been that participants can also receive diagnoses through the thoughtful and customized application of approaches and resources that are readily available in clinical settings.

METHODS: The UDN Genetic Counseling and Testing Working Group collected case vignettes that illustrated how clinically available methods resulted in diagnoses. The case vignettes were classified into three themes; phenotypic considerations, selection of genetic testing, and evaluating exome/GS variants and data.

RESULTS: We present 12 participants that illustrate how clinical practices such as phenotype-driven genomic investigations, consideration of variable expressivity, selecting the relevant tissue of interest for testing, utilizing updated testing platforms, and recognition of alternate transcript nomenclature resulted in diagnoses.

CONCLUSION: These examples demonstrate that when a diagnosis is elusive, an iterative patient-specific approach utilizing assessment options available to clinical providers may solve a portion of cases. However, this does require increased provider time commitment, a particular challenge in the current practice of genomics.

}, keywords = {Adolescent, Child, Child, Preschool, Databases, Factual, Diagnosis, Computer-Assisted, Female, Genetic Diseases, Inborn, Genetic Testing, Humans, Information Dissemination, Male, Middle Aged, Missed Diagnosis, National Institutes of Health (U.S.), Phenotype, Precision Medicine, Undiagnosed Diseases, United States, Young Adult}, issn = {2324-9269}, doi = {10.1002/mgg3.1397}, author = {Cope, Heidi and Spillmann, Rebecca and Rosenfeld, Jill A and Brokamp, Elly and Signer, Rebecca and Schoch, Kelly and Kelley, Emily G and Sullivan, Jennifer A and Macnamara, Ellen and Lincoln, Sharyn and Golden-Grant, Katie and Orengo, James P and Clark, Gary and Burrage, Lindsay C and Posey, Jennifer E and Punetha, Jaya and Robertson, Amy and Cogan, Joy and Phillips, John A and Martinez-Agosto, Julian and Shashi, Vandana} }