Clinical, pathologic, and mutational spectrum of dystroglycanopathy caused by LARGE mutations

J Neuropathol Exp Neurol. 2014 May;73(5):425-41. doi: 10.1097/NEN.0000000000000065.

Abstract

Dystroglycanopathies are a subtype of congenital muscular dystrophy of varying severity that can affect the brain and eyes, ranging from Walker-Warburg syndrome with severe brain malformation to milder congenital muscular dystrophy presentations with affected or normal cognition and later onset. Mutations in dystroglycanopathy genes affect a specific glycoepitope on α-dystroglycan; of the 14 genes implicated to date, LARGE encodes the glycosyltransferase that adds the final xylose and glucuronic acid, allowing α-dystroglycan to bind ligands, including laminin 211 and neurexin. Only 11 patients with LARGE mutations have been reported. We report the clinical, neuroimaging, and genetic features of 4 additional patients. We confirm that gross deletions and rearrangements are important mutational mechanisms for LARGE. The brain abnormalities overshadowed the initially mild muscle phenotype in all 4 patients. We present the first comprehensive postnatal neuropathology of the brain, spinal cord, and eyes of a patient with a homozygous LARGE mutation at Cys443. In this patient, polymicrogyria was the predominant cortical malformation; densely festooned polymicrogyria were overlaid by a continuous agyric surface. In view of the severity of these abnormalities, Cys443 may be a functionally important residue in the LARGE protein, whereas the mutation p.Glu509Lys of Patient 1 in this study may confer a milder phenotype. Overall, these results expand the clinical and genetic spectrum of dystroglycanopathy.

Publication types

  • Case Reports

MeSH terms

  • Child
  • Child, Preschool
  • Dystroglycans / genetics*
  • Fatal Outcome
  • Female
  • Homozygote
  • Humans
  • Infant
  • Male
  • Muscular Dystrophies / diagnosis
  • Muscular Dystrophies / genetics*
  • Muscular Dystrophies / pathology*
  • Mutation / genetics*
  • N-Acetylglucosaminyltransferases / genetics*
  • Pedigree
  • Polymorphism, Single Nucleotide / genetics

Substances

  • DAG1 protein, human
  • Dystroglycans
  • LARGE1 protein, human
  • N-Acetylglucosaminyltransferases