Leukoencephalopathy with calcifications and cysts: Genetic and phenotypic spectrum

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Yanick J Crow
  • Heather Marshall
  • Luis Seabra
  • Kristin Baranano
  • Roberta Battini
  • Andrea Berger
  • Edward Blair
  • Thomas Blauwblomme
  • Francois Bolduc
  • Natalie Boddaert
  • Johannes Buckard
  • Heather Burnett
  • Sophie Calvert
  • Roseline Caumes
  • Andy Cheuk-Him Ng
  • Diana Chiang
  • David B Clifford
  • Duccio M Cordelli
  • Anna de Burca
  • Natasha Demic
  • Isabelle Desguerre
  • Liesbeth De Waele
  • Alessio Di Fonzo
  • S Richard Dunham
  • Sarah Dyack
  • Frances Elmslie
  • Mickaël Ferrand
  • Gemma Fisher
  • Ehsan Ghayoor Karimiani
  • Jamal Ghoumid
  • Frances Gibbon
  • Himanshu Goel
  • Hilde T Hilmarsen
  • Imelda Hughes
  • Anu Jacob
  • Elizabeth A Jones
  • Ram Kumar
  • Richard J Leventer
  • Shelley MacDonald
  • Reza Maroofian
  • Sarju G Mehta
  • Imke Metz
  • Edoardo Monfrini
  • Daniela Neumann
  • Michael Noetzel
  • Mary O'Driscoll
  • Katrin Õunap
  • Axel Panzer
  • Sumit Parikh
  • Prab Prabhakar
  • Francis Ramond
  • Richard Sandford
  • Russell Saneto
  • Calvin Soh
  • Chloe A Stutterd
  • Gopinath M Subramanian
  • Kevin Talbot
  • Rhys H Thomas
  • Camilo Toro
  • Renaud Touraine
  • Emma Wakeling
  • Evangeline Wassmer
  • Andrea Whitney
  • John H Livingston
  • Andrew P Badrock

Abstract

Biallelic mutations in SNORD118, encoding the small nucleolar RNA U8, cause leukoencephalopathy with calcifications and cysts (LCC). Given the difficulty in interpreting the functional consequences of variants in nonprotein encoding genes, and the high allelic polymorphism across SNORD118 in controls, we set out to provide a description of the molecular pathology and clinical spectrum observed in a cohort of patients with LCC. We identified 64 affected individuals from 56 families. Age at presentation varied from 3 weeks to 67 years, with disease onset after age 40 years in eight patients. Ten patients had died. We recorded 44 distinct, likely pathogenic, variants in SNORD118. Fifty two of 56 probands were compound heterozygotes, with parental consanguinity reported in only three families. Forty nine of 56 probands were either heterozygous (46) or homozygous (three) for a mutation involving one of seven nucleotides that facilitate a novel intramolecular interaction between the 5' end and 3' extension of precursor-U8. There was no obvious genotype-phenotype correlation to explain the marked variability in age at onset. Complementing recently published functional analyses in a zebrafish model, these data suggest that LCC most often occurs due to combinatorial severe and milder mutations, with the latter mostly affecting 3' end processing of precursor-U8.

Bibliographical metadata

Original languageEnglish
JournalAmerican Journal of Medical Genetics. Part A
Early online date7 Oct 2020
DOIs
Publication statusPublished - 7 Oct 2020