title: COL4A1 mutations in patients with sporadic late-onset intracerebral hemorrhage.
abstract: OBJECTIVE
  Mutations in the type IV collagen alpha 1 gene (COL4A1) cause dominantly inherited cerebrovascular disease. We seek to determine the extent to which COL4A1 mutations contribute to sporadic, nonfamilial, intracerebral hemorrhages (ICHs).
  
  
  METHODS
  We sequenced COL4A1 in 96 patients with sporadic ICH. The presence of putative mutations was tested in 145 ICH-free controls. The effects of rare coding variants on COL4A1 biosynthesis were compared to previously validated mutations that cause porencephaly, small vessel disease, and hereditary angiopathy, nephropathy, aneurysms, and cramps (HANAC) syndrome.
  
  
  RESULTS
  We identified 2 rare nonsynonymous variants in ICH patients that were not detected in controls, 2 rare nonsynonymous variants in controls that were not detected in patients, and 2 common nonsynonymous variants that were detected in patients and controls. No variant found in controls affected COL4A1 biosynthesis. Both variants (COL4A1(P352L) and COL4A1(R538G)) found only in patients changed conserved amino acids and impaired COL4A1 secretion much like mutations that cause familial cerebrovascular disease.
  
  
  CONCLUSIONS
  This is the first assessment of the broader role for COL4A1 mutations in the etiology of ICH beyond a contribution to rare and severe familial cases and the first functional evaluation of the biosynthetic consequences of an allelic series of COL4A1 mutations that cause cerebrovascular disease. We identified 2 putative mutations in 96 patients with sporadic ICH and showed that these and other previously validated mutations inhibit secretion of COL4A1. Our data support the hypothesis that increased intracellular accumulation of COL4A1, decreased extracellular COL4A1, or both, contribute to sporadic cerebrovascular disease and ICH.
authors.affiliation: Department of Ophthalmology, Institute for Human Genetics, UCSF School of Medicine, San Francisco, CA, USA.
authors.forename: Yi-Chinn
authors.initials: YC
authors.lastname: Weng
authors.forename: Akshata
authors.initials: A
authors.lastname: Sonni
authors.forename: Cassandre
authors.initials: C
authors.lastname: Labelle-Dumais
authors.forename: Michelle
authors.initials: M
authors.lastname: de Leau
authors.forename: W Berkeley
authors.initials: WB
authors.lastname: Kauffman
authors.forename: Marion
authors.initials: M
authors.lastname: Jeanne
authors.forename: Alessandro
authors.initials: A
authors.lastname: Biffi
authors.forename: Steven M
authors.initials: SM
authors.lastname: Greenberg
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rosand
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Gould
mesh_terms: D000368:Aged; D000595:Amino Acid Sequence; D015153:Blotting, Western; D002543:Cerebral Hemorrhage / Q000235:genetics*; D002561:Cerebrovascular Disorders / Q000235:genetics; D024141:Collagen Type IV / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation
chemical_list: C547475:COL4A1 protein, human; D024141:Collagen Type IV