2. Academic Validation
  3. Germline recessive mutations in PI4KA are associated with perisylvian polymicrogyria, cerebellar hypoplasia and arthrogryposis

Germline recessive mutations in PI4KA are associated with perisylvian polymicrogyria, cerebellar hypoplasia and arthrogryposis

  • Hum Mol Genet. 2015 Jul 1;24(13):3732-41. doi: 10.1093/hmg/ddv117.
Alistair T Pagnamenta 1,  Malcolm F Howard 1,  Eva Wisniewski 2,  Niko Popitsch 1,  Samantha J L Knight 1,  David A Keays 3,  Gerardine Quaghebeur 4,  Helen Cox 5,  Phillip Cox 6,  Tamas Balla 2,  Jenny C Taylor 1,  Usha Kini 7
Affiliations

Affiliations

  • 1 National Institute for Health Research Biomedical Research Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
  • 2 Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD 20892, USA.
  • 3 Institute of Molecular Pathology, Vienna 1030, Austria.
  • 4 Department of Neuroradiology.
  • 5 West Midlands Regional Clinical Genetics Service, Clinical Genetics Unit and.
  • 6 Department of Histopathology, Birmingham Women's Hospital NHS Foundation Trust, Birmingham B15 2TG, UK.
  • 7 Department of Clinical Genetics, Oxford University Hospitals NHS Trust, Oxford OX3 9DU, UK, usha.kini@ouh.nhs.uk.
PMID: 25855803 DOI: 10.1093/hmg/ddv117
Abstract

Polymicrogyria (PMG) is a structural brain abnormality involving the cerebral cortex that results from impaired neuronal migration and although several genes have been implicated, many cases remain unsolved. In this study, exome Sequencing in a family where three fetuses had all been diagnosed with PMG and cerebellar hypoplasia allowed us to identify regions of the genome for which both chromosomes were shared identical-by-descent, reducing the search space for causative variants to 8.6% of the genome. In these regions, the only plausibly pathogenic mutations were compound heterozygous variants in PI4KA, which Sanger Sequencing confirmed segregated consistent with autosomal recessive inheritance. The paternally transmitted variant predicted a premature stop mutation (c.2386C>T; p.R796X), whereas the maternally transmitted variant predicted a missense substitution (c.5560G>A; p.D1854N) at a conserved residue within the catalytic domain. Functional studies using expressed wild-type or mutant PI4KA Enzyme confirmed the importance of p.D1854 for kinase activity. Our results emphasize the importance of phosphoinositide signalling in early brain development.

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