@article {37, title = {Biallelic Mutations in Citron Kinase Link Mitotic Cytokinesis to Human Primary Microcephaly.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Aug 04}, pages = {501-10}, abstract = {

Cell division terminates with cytokinesis and cellular separation. Autosomal-recessive primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by a reduction in brain and head size at birth in addition to non-progressive intellectual disability. MCPH is genetically heterogeneous, and 16 loci are known to be associated with loss-of-function mutations predominantly affecting centrosomal-associated proteins, but the multiple roles of centrosomes in cellular function has left questions about etiology. Here, we identified three families affected by homozygous missense mutations in CIT, encoding citron rho-interacting kinase (CIT), which has established roles in cytokinesis. All mutations caused substitution of conserved amino acid residues in the kinase domain and impaired kinase activity. Neural progenitors that were differentiated from induced pluripotent stem cells (iPSCs) derived from individuals with these mutations exhibited abnormal cytokinesis with delayed mitosis, multipolar spindles, and increased apoptosis, rescued by CRISPR/Cas9 genome editing. Our results highlight the importance of cytokinesis in the pathology of primary microcephaly.

}, keywords = {Alleles, Apoptosis, Centrosome, Child, Child, Preschool, Cytokinesis, Female, Genes, Recessive, Humans, Infant, Newborn, Intracellular Signaling Peptides and Proteins, Male, Microcephaly, Mitosis, Mutation, Missense, Pedigree, Protein Serine-Threonine Kinases}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.07.004}, author = {Li, Hongda and Bielas, Stephanie L and Zaki, Maha S and Ismail, Samira and Farfara, Dorit and Um, Kyongmi and Rosti, Rasim O and Scott, Eric C and Tu, Shu and Chi, Neil C and Gabriel, Stacey and Erson-Omay, Emine Z and Ercan-Sencicek, A Gulhan and Yasuno, Katsuhito and {\c C}a{\u g}layan, Ahmet Okay and Kaymak{\c c}alan, Hande and Ekici, Bar{\i}{\c s} and Bilguvar, Kaya and G{\"u}nel, Murat and Gleeson, Joseph G} } @article {71, title = {Genome-Wide Association and Exome Sequencing Study of Language Disorder in an Isolated Population.}, journal = {Pediatrics}, volume = {137}, year = {2016}, month = {2016 04}, abstract = {

BACKGROUND AND OBJECTIVE: Developmental language disorder (DLD) is a highly prevalent neurodevelopmental disorder associated with negative outcomes in different domains; the etiology of DLD is unknown. To investigate the genetic underpinnings of DLD, we performed genome-wide association and whole exome sequencing studies in a geographically isolated population with a substantially elevated prevalence of the disorder (ie, the AZ sample).

METHODS: DNA samples were collected from 359 individuals for the genome-wide association study and from 12 severely affected individuals for whole exome sequencing. Multifaceted phenotypes, representing major domains of expressive language functioning, were derived from collected speech samples.

RESULTS: Gene-based analyses revealed a significant association between SETBP1 and complexity of linguistic output (P = 5.47 {\texttimes} 10(-7)). The analysis of exome variants revealed coding sequence variants in 14 genes, most of which play a role in neural development. Targeted enrichment analysis implicated myocyte enhancer factor-2 (MEF2)-regulated genes in DLD in the AZ population. The main findings were successfully replicated in an independent cohort of children at risk for related disorders (n = 372).

CONCLUSIONS: MEF2-regulated pathways were identified as potential candidate pathways in the etiology of DLD. Several genes (including the candidate SETBP1 and other MEF2-related genes) seem to jointly influence certain, but not all, facets of the DLD phenotype. Even when genetic and environmental diversity is reduced, DLD is best conceptualized as etiologically complex. Future research should establish whether the signals detected in the AZ population can be replicated in other samples and languages and provide further characterization of the identified pathway.

}, keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Child, Child, Preschool, Exome, Genome-Wide Association Study, Humans, Language Disorders, Middle Aged, Polymorphism, Single Nucleotide, Russia, Sequence Analysis, DNA, Young Adult}, issn = {1098-4275}, doi = {10.1542/peds.2015-2469}, author = {Kornilov, Sergey A and Rakhlin, Natalia and Koposov, Roman and Lee, Maria and Yrigollen, Carolyn and {\c C}a{\u g}layan, Ahmet Okay and Magnuson, James S and Mane, Shrikant and Chang, Joseph T and Grigorenko, Elena L} } @article {23, title = {Mutations in MBOAT7, Encoding Lysophosphatidylinositol Acyltransferase I, Lead to Intellectual Disability Accompanied by Epilepsy and Autistic Features.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Oct 06}, pages = {912-916}, abstract = {

The risk of epilepsy among individuals with intellectual disability (ID) is approximately ten times that of the general population. From a cohort of >5,000 families affected by neurodevelopmental disorders, we identified six consanguineous families harboring homozygous inactivating variants in MBOAT7, encoding lysophosphatidylinositol acyltransferase (LPIAT1). Subjects presented with ID frequently accompanied by epilepsy and autistic features. LPIAT1 is a membrane-bound phospholipid-remodeling enzyme that transfers arachidonic acid (AA) to lysophosphatidylinositol to produce AA-containing phosphatidylinositol. This study suggests a role for AA-containing phosphatidylinositols in the development of ID accompanied by epilepsy and autistic features.

}, keywords = {Acyltransferases, Arachidonic Acid, Autistic Disorder, Child, Child, Preschool, Consanguinity, Epilepsy, Female, Homozygote, Humans, Infant, Intellectual Disability, Lysophospholipids, Male, Membrane Proteins, Mutation, Pedigree, Phosphatidylinositols}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.07.019}, author = {Johansen, Anide and Rosti, Rasim O and Musaev, Damir and Sticca, Evan and Harripaul, Ricardo and Zaki, Maha and {\c C}a{\u g}layan, Ahmet Okay and Azam, Matloob and Sultan, Tipu and Froukh, Tawfiq and Reis, Andr{\'e} and Popp, Bernt and Ahmed, Iltaf and John, Peter and Ayub, Muhammad and Ben-Omran, Tawfeg and Vincent, John B and Gleeson, Joseph G and Abou Jamra, Rami} } @article {223, title = {NGLY1 mutation causes neuromotor impairment, intellectual disability, and neuropathy.}, journal = {Eur J Med Genet}, volume = {58}, year = {2015}, month = {2015 Jan}, pages = {39-43}, abstract = {

N-glycanase 1 (NGLY1) is a conserved enzyme that is responsible for the deglycosylation of misfolded N-glycosylated proteins in the cytoplasm prior to their proteasome-mediated degradation. Disruption of this degradation process has been associated with various neurologic diseases including amyotrophic lateral sclerosis and Parkinson{\textquoteright}s disease. Here, we describe two siblings with neuromotor impairment, apparent intellectual disability, corneal opacities, and neuropathy who were found to possess a novel homozygous frame-shift mutation due to a 4 base pair deletion in NGLY1 (c.1533_1536delTCAA, p.Asn511LysfsX51). We hypothesize that this mutation likely limits the capability of neuronal cells to respond to stress due to accumulation of misfolded proteins, thereby impairing their survival and resulting in progressive loss of neurological function.

}, keywords = {Abnormalities, Multiple, Adolescent, Child, Corneal Opacity, Developmental Disabilities, Female, Frameshift Mutation, Genotype, Humans, Intellectual Disability, Male, Movement Disorders, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase, Peripheral Nervous System Diseases}, issn = {1878-0849}, doi = {10.1016/j.ejmg.2014.08.008}, author = {{\c C}a{\u g}layan, Ahmet Okay and Comu, Sinan and Baranoski, Jacob F and Parman, Yesim and Kaymak{\c c}alan, Hande and Akg{\"u}m{\"u}{\c s}, G{\"o}zde Tu{\u g}ce and Caglar, Caner and D{\"o}len, Duygu and Erson-Omay, Emine Zeynep and Harmanci, Akdes Serin and Mishra-Gorur, Ketu and Freeze, Hudson H and Yasuno, Katsuhito and Bilguvar, Kaya and G{\"u}nel, Murat} }