title: Complete callosal agenesis, pontocerebellar hypoplasia, and axonal neuropathy due to AMPD2 loss.
abstract: OBJECTIVE
  To determine the molecular basis of a severe neurologic disorder in a large consanguineous family with complete agenesis of the corpus callosum (ACC), pontocerebellar hypoplasia (PCH), and peripheral axonal neuropathy.
  
  
  METHODS
  Assessment included clinical evaluation, neuroimaging, and nerve conduction studies (NCSs). Linkage analysis used genotypes from 7 family members, and the exome of 3 affected siblings was sequenced. Molecular analyses used Sanger sequencing to perform segregation studies and cohort analysis and Western blot of patient-derived cells.
  
  
  RESULTS
  Affected family members presented with postnatal microcephaly and profound developmental delay, with early death in 3. Neuroimaging, including a fetal MRI at 30 weeks, showed complete ACC and PCH. Clinical evaluation showed areflexia, and NCSs revealed a severe axonal neuropathy in the 2 individuals available for electrophysiologic study. A novel homozygous stopgain mutation in adenosine monophosphate deaminase 2 (AMPD2) was identified within the linkage region on chromosome 1. Molecular analyses confirmed that the mutation segregated with disease and resulted in the loss of AMPD2. Subsequent screening of a cohort of 42 unrelated individuals with related imaging phenotypes did not reveal additional AMPD2 mutations.
  
  
  CONCLUSIONS
  We describe a family with a novel stopgain mutation in AMPD2. We expand the phenotype recently described as PCH type 9 to include progressive postnatal microcephaly, complete ACC, and peripheral axonal neuropathy. Screening of additional individuals with related imaging phenotypes failed to identify mutations in AMPD2, suggesting that AMPD2 mutations are not a common cause of combined callosal and pontocerebellar defects.
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Ashley P L
authors.initials: AP
authors.lastname: Marsh
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Lukic
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Kate
authors.initials: K
authors.lastname: Pope
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Catherine
authors.initials: C
authors.lastname: Bromhead
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Rick
authors.initials: R
authors.lastname: Tankard
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Monique M
authors.initials: MM
authors.lastname: Ryan
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Eppie M
authors.initials: EM
authors.lastname: Yiu
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Joe C H
authors.initials: JC
authors.lastname: Sim
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Martin B
authors.initials: MB
authors.lastname: Delatycki
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Amor
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: George
authors.initials: G
authors.lastname: McGillivray
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Elliott H
authors.initials: EH
authors.lastname: Sherr
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Melanie
authors.initials: M
authors.lastname: Bahlo
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Leventer
authors.affiliation: Bruce Lefroy Centre for Genetic Health Research (A.P.L.M., K.P., E.M.Y., J.C.H.S., M.B.D., P.J.L.), Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia; Bioinformatics Division (V.L., C.B., R.T., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Neurology (M.M.R., E.M.Y., R.J.L.) and Department of Paediatrics (A.P.L.M., M.M.R., E.M.Y., M.B.D., D.J.A., R.J.L., P.J.L.), The University of Melbourne, Royal Children's Hospital, Parkville, Australia; Victorian Clinical Genetics Services (D.J.A., G.M.) and Neuroscience Research (M.M.R., R.J.L.), Murdoch Childrens Research Institute, Parkville, Australia; Department of Neurology (E.H.S.), UCSF Benioff Children's Hospital, San Francisco, CA; Clinical Genetics (M.B.D.), Austin Health, Heidelberg, Australia; and Department of Mathematics and Statistics (M.B.) and Department of Medical Biology (R.T., M.B.), The University of Melbourne, Parkville, Australia.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lockhart