2. Academic Validation
  3. Biallelic COLGALT1 variants are associated with cerebral small vessel disease

Biallelic COLGALT1 variants are associated with cerebral small vessel disease

  • Ann Neurol. 2018 Dec;84(6):843-853. doi: 10.1002/ana.25367.
Satoko Miyatake 1 2,  Sacha Schneeberger 3,  Norihisa Koyama 4,  Kenji Yokochi 4 5,  Kayo Ohmura 6,  Masaaki Shiina 7,  Harushi Mori 8,  Eriko Koshimizu 1,  Eri Imagawa 1,  Yuri Uchiyama 1,  Satomi Mitsuhashi 1,  Martin C Frith 9 10 11,  Atsushi Fujita 1,  Mai Satoh 1,  Masataka Taguri 12,  Yasuko Tomono 13,  Keita Takahashi 14,  Hiroshi Doi 14,  Hideyuki Takeuchi 14,  Mitsuko Nakashima 1 15,  Takeshi Mizuguchi 1,  Atsushi Takata 1,  Noriko Miyake 1,  Hirotomo Saitsu 1 15,  Fumiaki Tanaka 14,  Kazuhiro Ogata 7,  Thierry Hennet 3,  Naomichi Matsumoto 1
Affiliations

Affiliations

  • 1 Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
  • 2 Clinical Genetics Department, Yokohama City University Hospital, Yokohama, Japan.
  • 3 Institute of Physiology, University of Zurich, Zurich, Switzerland.
  • 4 Department of Pediatrics, Toyohashi Municipal Hospital, Toyohashi, Japan.
  • 5 Department of Pediatrics, Seirei Mikatahara General Hospital, Shizuoka, Japan.
  • 6 Department of Pediatric Neurology, Morinomiya Hospital, Osaka, Japan.
  • 7 Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
  • 8 Department of Radiology, Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan.
  • 9 Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan.
  • 10 Graduate School of Frontier Sciences, University of Tokyo, Chiba, Japan.
  • 11 Computational Bio Big-Data Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan.
  • 12 Department of Data Science, Yokohama City University School of Data Science, Yokohama, Japan.
  • 13 Division of Molecular and Cell Biology, Shigei Medical Research Institute, Okayama, Japan.
  • 14 Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
  • 15 Department of Biochemistry, Hamamatsu University School of Medicine, Shizuoka, Japan.
PMID: 30412317 DOI: 10.1002/ana.25367
Abstract

Objective: Approximately 5% of cerebral small vessel diseases are hereditary, which include COL4A1/COL4A2-related disorders. COL4A1/COL4A2 encode type IV collagen α1/2 chains in the basement membranes of cerebral vessels. COL4A1/COL4A2 mutations impair the secretion of collagen to the extracellular matrix, thereby resulting in vessel fragility. The diagnostic yield for COL4A1/COL4A2 variants is around 20 to 30%, suggesting other mutated genes might be associated with this disease. This study aimed to identify novel genes that cause COL4A1/COL4A2-related disorders.

Methods: Whole exome sequencing was performed in 2 families with suspected COL4A1/COL4A2-related disorders. We validated the role of COLGALT1 variants by constructing a 3-dimensional structural model, evaluating collagen β (1-O) galactosyltransferase 1 (ColGalT1) protein expression and ColGalT activity by Western blotting and collagen galactosyltransferase assays, and performing in vitro RNA interference and rescue experiments.

Results: Exome sequencing demonstrated biallelic variants in COLGALT1 encoding ColGalT1, which was involved in the post-translational modification of type IV collagen in 2 unrelated patients: c.452 T > G (p.Leu151Arg) and c.1096delG (p.Glu366Argfs*15) in Patient 1, and c.460G > C (p.Ala154Pro) and c.1129G > C (p.Gly377Arg) in Patient 2. Three-dimensional model analysis suggested that p.Leu151Arg and p.Ala154Pro destabilized protein folding, which impaired enzymatic activity. ColGalT1 protein expression and ColGalT activity in Patient 1 were undetectable. RNA interference studies demonstrated that reduced ColGalT1 altered COL4A1 secretion, and rescue experiments showed that mutant COLGALT1 insufficiently restored COL4A1 production in cells compared with wild type.

Interpretation: Biallelic COLGALT1 variants cause cerebral small vessel abnormalities through a common molecular pathogenesis with COL4A1/COL4A2-related disorders. Ann Neurol 2018;84:843-853.

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