@article {205, title = {Biallelic truncating mutations in FMN2, encoding the actin-regulatory protein Formin 2, cause nonsyndromic autosomal-recessive intellectual disability.}, journal = {Am J Hum Genet}, volume = {95}, year = {2014}, month = {2014 Dec 04}, pages = {721-8}, abstract = {

Dendritic spines represent the major site of neuronal activity in the brain; they serve as the receiving point for neurotransmitters and undergo rapid activity-dependent morphological changes that correlate with learning and memory. Using a combination of homozygosity mapping and next-generation sequencing in two consanguineous families affected by nonsyndromic autosomal-recessive intellectual disability, we identified truncating mutations in formin 2 (FMN2), encoding a protein that belongs to the formin family of actin cytoskeleton nucleation factors and is highly expressed in the maturing brain. We found that FMN2 localizes to punctae along dendrites and that germline inactivation of mouse Fmn2 resulted in animals with decreased spine density; such mice were previously demonstrated to have a conditioned fear-learning defect. Furthermore, patient neural cells derived from induced pluripotent stem cells showed correlated decreased synaptic density. Thus, FMN2 mutations link intellectual disability either directly or indirectly to the regulation of actin-mediated synaptic spine density.

}, keywords = {Adolescent, Adult, Base Sequence, Chromosome Disorders, Cohort Studies, Consanguinity, Egypt, Exome, Female, Genes, Recessive, Genetic Linkage, High-Throughput Nucleotide Sequencing, Homozygote, Humans, Intellectual Disability, Male, Microfilament Proteins, Molecular Sequence Data, Nuclear Proteins, Pakistan, Pedigree, Sequence Analysis, DNA, Sequence Deletion}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.10.016}, author = {Law, Rosalind and Dixon-Salazar, Tracy and Jerber, Julie and Cai, Na and Abbasi, Ansar A and Zaki, Maha S and Mittal, Kirti and Gabriel, Stacey B and Rafiq, Muhammad Arshad and Khan, Valeed and Nguyen, Maria and Ali, Ghazanfar and Copeland, Brett and Scott, Eric and Vasli, Nasim and Mikhailov, Anna and Khan, Muhammad Nasim and Andrade, Danielle M and Ayaz, Muhammad and Ansar, Muhammad and Ayub, Muhammad and Vincent, John B and Gleeson, Joseph G} } @article {252, title = {CLP1 founder mutation links tRNA splicing and maturation to cerebellar development and neurodegeneration.}, journal = {Cell}, volume = {157}, year = {2014}, month = {2014 Apr 24}, pages = {651-63}, abstract = {

Neurodegenerative diseases can occur so early as to affect neurodevelopment. From a cohort of more than 2,000 consanguineous families with childhood neurological disease, we identified a founder mutation in four independent pedigrees in cleavage and polyadenylation factor I subunit 1 (CLP1). CLP1 is a multifunctional kinase implicated in tRNA, mRNA, and siRNA maturation. Kinase activity of the CLP1 mutant protein was defective, and the tRNA endonuclease complex (TSEN) was destabilized, resulting in impaired pre-tRNA cleavage. Germline clp1 null zebrafish showed cerebellar neurodegeneration that was rescued by wild-type, but not mutant, human CLP1 expression. Patient-derived induced neurons displayed both depletion of mature tRNAs and accumulation of unspliced pre-tRNAs. Transfection of partially processed tRNA fragments into patient cells exacerbated an oxidative stress-induced reduction in cell survival. Our data link tRNA maturation to neuronal development and neurodegeneration through defective CLP1 function in humans.

}, keywords = {Animals, Brain, Cerebellum, Cleavage And Polyadenylation Specificity Factor, Female, Humans, Male, Mice, Models, Molecular, Neurodegenerative Diseases, Nuclear Proteins, Pedigree, Phosphotransferases, RNA Splicing, RNA, Transfer, Saccharomyces cerevisiae, Transcription Factors, Zebrafish, Zebrafish Proteins}, issn = {1097-4172}, doi = {10.1016/j.cell.2014.03.049}, author = {Schaffer, Ashleigh E and Eggens, Veerle R C and {\c C}a{\u g}layan, Ahmet Okay and Reuter, Miriam S and Scott, Eric and Coufal, Nicole G and Silhavy, Jennifer L and Xue, Yuanchao and Kayserili, H{\"u}lya and Yasuno, Katsuhito and Rosti, Rasim Ozgur and Abdellateef, Mostafa and Caglar, Caner and Kasher, Paul R and Cazemier, J Leonie and Weterman, Marian A and Cantagrel, Vincent and Cai, Na and Zweier, Christiane and Altunoglu, Umut and Satkin, N Bilge and Aktar, Fesih and Tuysuz, Beyhan and Yalcinkaya, Cengiz and Caksen, Huseyin and Bilguvar, Kaya and Fu, Xiang-Dong and Trotta, Christopher R and Gabriel, Stacey and Reis, Andr{\'e} and G{\"u}nel, Murat and Baas, Frank and Gleeson, Joseph G} } @article {278, title = {Mutations in CSPP1 lead to classical Joubert syndrome.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 Jan 02}, pages = {80-6}, abstract = {

Joubert syndrome and related disorders (JSRDs) are genetically heterogeneous and characterized by a distinctive mid-hindbrain malformation. Causative mutations lead to primary cilia dysfunction, which often results in variable involvement of other organs such as the liver, retina, and kidney. We identified predicted null mutations in CSPP1 in six individuals affected by classical JSRDs. CSPP1 encodes a protein localized to centrosomes and spindle poles, as well as to the primary cilium. Despite the known interaction between CSPP1 and nephronophthisis-associated proteins, none of the affected individuals in our cohort presented with kidney disease, and further, screening of a large cohort of individuals with nephronophthisis demonstrated no mutations. CSPP1 is broadly expressed in neural tissue, and its encoded protein localizes to the primary cilium in an in~vitro model of human neurogenesis. Here, we show abrogated protein levels and ciliogenesis in affected fibroblasts. Our data thus suggest that CSPP1 is involved in neural-specific functions of primary cilia.

}, keywords = {Abnormalities, Multiple, Brain, Cell Cycle Proteins, Centrosome, Cerebellar Diseases, Cerebellum, Cilia, Cohort Studies, Eye Abnormalities, Fibroblasts, Gene Deletion, Humans, Image Processing, Computer-Assisted, Kidney Diseases, Cystic, Microtubule-Associated Proteins, Polymorphism, Single Nucleotide, Retina}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.11.015}, author = {Akizu, Naiara and Silhavy, Jennifer L and Rosti, Rasim Ozgur and Scott, Eric and Fenstermaker, Ali G and Schroth, Jana and Zaki, Maha S and Sanchez, Henry and Gupta, Neerja and Kabra, Madhulika and Kara, Majdi and Ben-Omran, Tawfeg and Rosti, Basak and Guemez-Gamboa, Alicia and Spencer, Emily and Pan, Roger and Cai, Na and Abdellateef, Mostafa and Gabriel, Stacey and Halbritter, Jan and Hildebrandt, Friedhelm and van Bokhoven, Hans and G{\"u}nel, Murat and Gleeson, Joseph G} }