A novel cerebello-ocular syndrome with abnormal glycosylation due to abnormalities in dolichol metabolism

Eva Morava*, Ron A. Wevers, Vincent Cantagrel, Lies H. Hoefsloot, Lihadh Al-Gazali, Jeroen Schoots, Arno van Rooij, Karin Huijben, Connie M. A. van Ravenswaaij-Arts, Marjolein C. J. Jongmans, Jolanta Sykut-Cegielska, Georg F. Hoffmann, Peter Bluemel, Maciej Adamowicz, Jeroen van Reeuwijk, Bobby G. Ng, Jorieke E. H. Bergman, Hans van Bokhoven, Christian Koerner, Dusica Babovic-VuksanovicMichel A. Willemsen, Joseph G. Gleeson, Ludwig Lehle, Arjan P. M. de Brouwer, Dirk J. Lefeber

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

68 Citations (Scopus)

Abstract

Cerebellar hypoplasia and slowly progressive ophthalmological symptoms are common features in patients with congenital disorders of glycosylation type I. In a group of patients with congenital disorders of glycosylation type I with unknown aetiology, we have previously described a distinct phenotype with severe, early visual impairment and variable eye malformations, including optic nerve hypoplasia, retinal coloboma, congenital cataract and glaucoma. Some of the symptoms overlapped with the phenotype in other congenital disorders of glycosylation type I subtypes, such as vermis hypoplasia, anaemia, ichtyosiform dermatitis, liver dysfunction and coagulation abnormalities. We recently identified pathogenic mutations in the SRD5A3 gene, encoding steroid 5 alpha-reductase type 3, in a group of patients who presented with this particular phenotype and a common metabolic pattern. Here, we report on the clinical, genetic and metabolic features of 12 patients from nine families with cerebellar ataxia and congenital eye malformations diagnosed with SRD5A3-congenital disorders of glycosylation due to steroid 5 alpha-reductase type 3 defect. This enzyme is necessary for the reduction of polyprenol to dolichol, the lipid anchor for N-glycosylation in the endoplasmic reticulum. Dolichol synthesis is an essential metabolic step in protein glycosylation. The current defect leads to a severely abnormal glycosylation state already in the early phase of the N-glycan biosynthesis pathway in the endoplasmic reticulum. We detected high expression of SRD5A3 in foetal brain tissue, especially in the cerebellum, consistent with the finding of the congenital cerebellar malformations. Based on the overlapping clinical, biochemical and genetic data in this large group of patients with congenital disorders of glycosylation, we define a novel syndrome of cerebellar ataxia associated with congenital eye malformations due to a defect in dolichol metabolism.

Original languageEnglish
Pages (from-to)3210-3220
Number of pages11
JournalBrain
Volume133
DOIs
Publication statusPublished - Nov-2010

Keywords

  • congenital disorders of glycosylation
  • SRD5A3-CDG
  • CDG type Iq
  • glycosylation
  • dolichol metabolism
  • polyprenol reductase
  • SRD5A3
  • vermis hypoplasia
  • coloboma
  • cataract
  • glaucoma
  • AUTOSOMAL RECESSIVE SYNDROME
  • CONGENITAL DISORDERS
  • CHARGE-SYNDROME
  • MENTAL-RETARDATION
  • JOUBERT-SYNDROME
  • CDG
  • MUTATIONS
  • GENE
  • BIOSYNTHESIS
  • SPECTRUM

Cite this