@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 {949, title = {A relatively common homozygous TRAPPC4 splicing variant is associated with an early-infantile neurodegenerative syndrome.}, journal = {Eur J Hum Genet}, volume = {29}, year = {2021}, month = {2021 Feb}, pages = {271-279}, abstract = {

Trafficking protein particle (TRAPP) complexes, which include the TRAPPC4 protein, regulate membrane trafficking between lipid organelles in a process termed vesicular tethering. TRAPPC4 was recently implicated in a recessive neurodevelopmental condition in four unrelated families due to a shared c.454+3A>G splice variant. Here, we report 23 patients from 17 independent families with an early-infantile-onset neurodegenerative presentation, where we also identified the homozygous variant hg38:11:119020256 A>G (NM_016146.5:c.454+3A>G) in TRAPPC4 through exome or genome sequencing. No other clinically relevant TRAPPC4 variants were identified among any of over 10,000 patients with neurodevelopmental conditions. We found the carrier frequency of TRAPPC4 c.454+3A>G was 2.4-5.4 per 10,000 healthy individuals. Affected individuals with the homozygous TRAPPC4 c.454+3A>G variant showed profound psychomotor delay, developmental regression, early-onset epilepsy, microcephaly and progressive spastic tetraplegia. Based upon RNA sequencing, the variant resulted in partial exon 3 skipping and generation of an aberrant transcript owing to use of a downstream cryptic splice donor site, predicting a premature stop codon and nonsense mediated decay. These data confirm the pathogenicity of the TRAPPC4 c.454+3A>G variant, and refine the clinical presentation of TRAPPC4-related encephalopathy.

}, issn = {1476-5438}, doi = {10.1038/s41431-020-00717-5}, author = {Ghosh, Shereen G and Scala, Marcello and Beetz, Christian and Helman, Guy and Stanley, Valentina and Yang, Xiaoxu and Breuss, Martin W and Mazaheri, Neda and Selim, Laila and Hadipour, Fatemeh and Pais, Lynn and Stutterd, Chloe A and Karageorgou, Vasiliki and Begtrup, Amber and Crunk, Amy and Juusola, Jane and Willaert, Rebecca and Flore, Leigh A and Kennelly, Kelly and Spencer, Christopher and Brown, Martha and Trapane, Pamela and Hurst, Anna C E and Lane Rutledge, S and Goodloe, Dana H and McDonald, Marie T and Shashi, Vandana and Schoch, Kelly and Tomoum, Hoda and Zaitoun, Raghda and Hadipour, Zahra and Galehdari, Hamid and Pagnamenta, Alistair T and Mojarrad, Majid and Sedaghat, Alireza and Dias, Patr{\'\i}cia and Quintas, Sofia and Eslahi, Atiyeh and Shariati, Gholamreza and Bauer, Peter and Simons, Cas and Houlden, Henry and Issa, Mahmoud Y and Zaki, MAH S and Maroofian, Reza and Gleeson, Joseph G} } @article {422, title = {Mutations in Fibronectin Cause a Subtype of Spondylometaphyseal Dysplasia with "Corner Fractures".}, journal = {Am J Hum Genet}, volume = {101}, year = {2017}, month = {2017 Nov 02}, pages = {815-823}, abstract = {

Fibronectin is a master organizer of extracellular matrices (ECMs) and promotes the assembly of collagens, fibrillin-1, and other proteins. It is also known to play roles in skeletal tissues through its secretion by osteoblasts, chondrocytes, and mesenchymal cells. Spondylometaphyseal dysplasias (SMDs) comprise a diverse group of skeletal dysplasias and often manifest as short stature, growth-plate irregularities, and vertebral anomalies, such as scoliosis. By comparing the exomes of individuals with SMD with the radiographic appearance of "corner fractures" at metaphyses, we identified three individuals with fibronectin (FN1) variants affecting highly conserved residues. Furthermore, using matching tools and the SkelDys emailing list, we identified other individuals with de novo~FN1 variants and a similar phenotype. The severe scoliosis in most individuals and rare developmental coxa vara distinguish individuals with FN1 mutations from those with classical Sutcliffe-type SMD. To study functional consequences of these FN1 mutations on the protein level, we introduced three disease-associated missense variants (p.Cys87Phe [c.260G>T], p.Tyr240Asp [c.718T>G], and p.Cys260Gly [c.778T>G]) into a recombinant secreted N-terminal 70~kDa fragment (rF70K) and the full-length fibronectin (rFN). The wild-type rF70K and rFN were secreted into the culture medium, whereas all mutant proteins were either not secreted or secreted at significantly lower amounts. Immunofluorescence analysis demonstrated increased intracellular retention of the mutant proteins. In summary, FN1 mutations that cause defective fibronectin secretion are found in SMD, and we thus provide additional evidence for a critical function of fibronectin in cartilage and bone.

}, keywords = {Adolescent, Adult, Bone and Bones, Bone Diseases, Developmental, Cartilage, Child, Child, Preschool, Exome, Female, Fibronectins, Fractures, Bone, Humans, Male, Mutation, Osteochondrodysplasias, Phenotype, Scoliosis}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2017.09.019}, author = {Lee, Chae Syng and Fu, He and Baratang, Nissan and Rousseau, Justine and Kumra, Heena and Sutton, V Reid and Niceta, Marcello and Ciolfi, Andrea and Yamamoto, Guilherme and Bertola, D{\'e}bora and Marcelis, Carlo L and Lugtenberg, Dorien and Bartuli, Andrea and Kim, Choel and Hoover-Fong, Julie and Sobreira, Nara and Pauli, Richard and Bacino, Carlos and Krakow, Deborah and Parboosingh, Jillian and Yap, Patrick and Kariminejad, Ariana and McDonald, Marie T and Aracena, Mariana I and Lausch, Ekkehart and Unger, Sheila and Superti-Furga, Andrea and Lu, James T and Cohn, Dan H and Tartaglia, Marco and Lee, Brendan H and Reinhardt, Dieter P and Campeau, Philippe M} }