@article {1001, title = {Loss of function mutations in GEMIN5 cause a neurodevelopmental disorder.}, journal = {Nat Commun}, volume = {12}, year = {2021}, month = {2021 05 07}, pages = {2558}, abstract = {

GEMIN5, an RNA-binding protein is essential for assembly of the survival motor neuron (SMN) protein complex and facilitates the formation of small nuclear ribonucleoproteins (snRNPs), the building blocks of spliceosomes. Here, we have identified 30 affected individuals from 22 unrelated families presenting with developmental delay, hypotonia, and cerebellar ataxia harboring biallelic variants in the GEMIN5 gene. Mutations in GEMIN5 perturb the subcellular distribution, stability, and expression of GEMIN5 protein and its interacting partners in patient iPSC-derived neurons, suggesting a potential loss-of-function mechanism. GEMIN5 mutations result in disruption of snRNP complex assembly formation in patient iPSC neurons. Furthermore, knock down of rigor mortis, the fly homolog of human GEMIN5, leads to developmental defects, motor dysfunction, and a reduced lifespan. Interestingly, we observed that GEMIN5 variants disrupt a distinct set of transcripts and pathways as compared to SMA patient neurons, suggesting different molecular pathomechanisms. These findings collectively provide evidence that pathogenic variants in GEMIN5 perturb physiological functions and result in a neurodevelopmental delay and ataxia syndrome.

}, keywords = {Alleles, Amino Acid Sequence, Animals, Child, Preschool, Developmental Disabilities, Drosophila, Female, Gene Expression Regulation, Developmental, Gene Knockdown Techniques, Gene Ontology, HEK293 Cells, Humans, Induced Pluripotent Stem Cells, Loss of Function Mutation, Male, Muscle Hypotonia, Myoclonic Cerebellar Dyssynergia, Neurodevelopmental Disorders, Neurons, Pedigree, Polymorphism, Single Nucleotide, Ribonucleoproteins, Small Nuclear, Rigor Mortis, RNA-Seq, SMN Complex Proteins}, issn = {2041-1723}, doi = {10.1038/s41467-021-22627-w}, author = {Kour, Sukhleen and Rajan, Deepa S and Fortuna, Tyler R and Anderson, Eric N and Ward, Caroline and Lee, Youngha and Lee, Sangmoon and Shin, Yong Beom and Chae, Jong-Hee and Choi, Murim and Siquier, Karine and Cantagrel, Vincent and Amiel, Jeanne and Stolerman, Elliot S and Barnett, Sarah S and Cousin, Margot A and Castro, Diana and McDonald, Kimberly and Kirmse, Brian and Nemeth, Andrea H and Rajasundaram, Dhivyaa and Innes, A Micheil and Lynch, Danielle and Frosk, Patrick and Collins, Abigail and Gibbons, Melissa and Yang, Michele and Desguerre, Isabelle and Boddaert, Nathalie and Gitiaux, Cyril and Rydning, Siri Lynne and Selmer, Kaja K and Urreizti, Roser and Garcia-Oguiza, Alberto and Osorio, Andr{\'e}s Nascimento and Verdura, Edgard and Pujol, Aurora and McCurry, Hannah R and Landers, John E and Agnihotri, Sameer and Andriescu, E Corina and Moody, Shade B and Phornphutkul, Chanika and Sacoto, Maria J Guillen and Begtrup, Amber and Houlden, Henry and Kirschner, Janbernd and Schorling, David and Rudnik-Sch{\"o}neborn, Sabine and Strom, Tim M and Leiz, Steffen and Juliette, Kali and Richardson, Randal and Yang, Ying and Zhang, Yuehua and Wang, Minghui and Wang, Jia and Wang, Xiaodong and Platzer, Konrad and Donkervoort, Sandra and B{\"o}nnemann, Carsten G and Wagner, Matias and Issa, Mahmoud Y and Elbendary, Hasnaa M and Stanley, Valentina and Maroofian, Reza and Gleeson, Joseph G and Zaki, MAH S and Senderek, Jan and Pandey, Udai Bhan} } @article {585, title = {Loss of the sphingolipid desaturase DEGS1 causes hypomyelinating leukodystrophy.}, journal = {J Clin Invest}, volume = {129}, year = {2019}, month = {2019 Mar 01}, pages = {1240-1256}, abstract = {

Sphingolipid imbalance is the culprit in a variety of neurological diseases, some affecting the myelin sheath. We have used whole-exome sequencing in patients with undetermined leukoencephalopathies to uncover the endoplasmic reticulum lipid desaturase DEGS1 as the causative gene in 19 patients from 13 unrelated families. Shared features among the cases include severe motor arrest, early nystagmus, dystonia, spasticity, and profound failure to thrive. MRI showed hypomyelination, thinning of the corpus callosum, and progressive thalamic and cerebellar atrophy, suggesting a critical role of DEGS1 in myelin development and maintenance. This enzyme converts dihydroceramide (DhCer) into ceramide (Cer) in the final step of the de novo biosynthesis pathway. We detected a marked increase of the substrate DhCer and DhCer/Cer ratios in patients{\textquoteright} fibroblasts and muscle. Further, we used a knockdown approach for disease modeling in Danio rerio, followed by a preclinical test with the first-line treatment for multiple sclerosis, fingolimod (FTY720, Gilenya). The enzymatic inhibition of Cer synthase by fingolimod, 1 step prior to DEGS1 in the pathway, reduced the critical DhCer/Cer imbalance and the severe locomotor disability, increasing the number of myelinating oligodendrocytes in a zebrafish model. These proof-of-concept results pave the way to clinical translation.

}, issn = {1558-8238}, doi = {10.1172/JCI123959}, author = {Pant, Devesh C and Dorboz, Imen and Schluter, Agatha and Fourcade, St{\'e}phane and Launay, Nathalie and Joya, Javier and Aguilera-Albesa, Sergio and Yoldi, Maria Eugenia and Casasnovas, Carlos and Willis, Mary J and Ruiz, Montserrat and Ville, Doroth{\'e}e and Lesca, Gaetan and Siquier-Pernet, Karine and Desguerre, Isabelle and Yan, Huifang and Wang, Jingmin and Burmeister, Margit and Brady, Lauren and Tarnopolsky, Mark and Cornet, Carles and Rubbini, Davide and Terriente, Javier and James, Kiely N and Musaev, Damir and Zaki, Maha S and Patterson, Marc C and Lanpher, Brendan C and Klee, Eric W and Pinto E Vairo, Filippo and Wohler, Elizabeth and Sobreira, Nara Lygia de M and Cohen, Julie S and Maroofian, Reza and Galehdari, Hamid and Mazaheri, Neda and Shariati, Gholamreza and Colleaux, Laurence and Rodriguez, Diana and Gleeson, Joseph G and Pujades, Cristina and Fatemi, Ali and Boespflug-Tanguy, Odile and Pujol, Aurora} } @article {179, title = {Biallelic mutations in SNX14 cause a syndromic form of cerebellar atrophy and lysosome-autophagosome dysfunction.}, journal = {Nat Genet}, volume = {47}, year = {2015}, month = {2015 May}, pages = {528-34}, abstract = {

Pediatric-onset ataxias often present clinically as developmental delay and intellectual disability, with prominent cerebellar atrophy as a key neuroradiographic finding. Here we describe a new clinically distinguishable recessive syndrome in 12 families with cerebellar atrophy together with ataxia, coarsened facial features and intellectual disability, due to truncating mutations in the sorting nexin gene SNX14, encoding a ubiquitously expressed modular PX domain-containing sorting factor. We found SNX14 localized to lysosomes and associated with phosphatidylinositol (3,5)-bisphosphate, a key component of late endosomes/lysosomes. Patient-derived cells showed engorged lysosomes and a slower autophagosome clearance rate upon autophagy induction by starvation. Zebrafish morphants for snx14 showed dramatic loss of cerebellar parenchyma, accumulation of autophagosomes and activation of apoptosis. Our results characterize a unique ataxia syndrome due to biallelic SNX14 mutations leading to lysosome-autophagosome dysfunction.

}, keywords = {Animals, Atrophy, Autophagy, Cerebellar Diseases, Cerebellum, Child, Preschool, Female, Gene Frequency, Humans, Infant, Lod Score, Lysosomal Storage Diseases, Lysosomes, Male, Mutation, Phagosomes, Sorting Nexins, Spinocerebellar Ataxias, Syndrome, Zebrafish}, issn = {1546-1718}, doi = {10.1038/ng.3256}, author = {Akizu, Naiara and Cantagrel, Vincent and Zaki, Maha S and Al-Gazali, Lihadh and Wang, Xin and Rosti, Rasim Ozgur and Dikoglu, Esra and Gelot, Antoinette Bernabe and Rosti, Basak and Vaux, Keith K and Scott, Eric M and Silhavy, Jennifer L and Schroth, Jana and Copeland, Brett and Schaffer, Ashleigh E and Gordts, Philip L S M and Esko, Jeffrey D and Buschman, Matthew D and Field, Seth J and Napolitano, Gennaro and Abdel-Salam, Ghada M and Ozgul, R Koksal and Sag{\i}roglu, Mahmut Samil and Azam, Matloob and Ismail, Samira and Aglan, Mona and Selim, Laila and Mahmoud, Iman G and Abdel-Hadi, Sawsan and Badawy, Amera El and Sadek, Abdelrahim A and Mojahedi, Faezeh and Kayserili, H{\"u}lya and Masri, Amira and Bastaki, Laila and Temtamy, Samia and M{\"u}ller, Ulrich and Desguerre, Isabelle and Casanova, Jean-Laurent and Dursun, Ali and G{\"u}nel, Murat and Gabriel, Stacey B and de Lonlay, Pascale and Gleeson, Joseph G} }