title: Whole-transcriptome sequencing in blood provides a diagnosis of spinal muscular atrophy with progressive myoclonic epilepsy.
abstract: At least 15% of the disease-causing mutations affect mRNA splicing. Many splicing mutations are missed in a clinical setting due to limitations of in silico prediction algorithms or their location in noncoding regions. Whole-transcriptome sequencing is a promising new tool to identify these mutations; however, it will be a challenge to obtain disease-relevant tissue for RNA. Here, we describe an individual with a sporadic atypical spinal muscular atrophy, in whom clinical DNA sequencing reported one pathogenic ASAH1 mutation (c.458A>G;p.Tyr153Cys). Transcriptome sequencing on patient leukocytes identified a highly significant and atypical ASAH1 isoform not explained by c.458A>G(p<10-16). Subsequent Sanger-sequencing identified the splice mutation responsible for the isoform (c.504A>C;p.Lys168Asn) and provided a molecular diagnosis of autosomal-recessive spinal muscular atrophy with progressive myoclonic epilepsy. Our findings demonstrate the utility of RNA sequencing from blood to identify splice-impacting disease mutations for nonhematological conditions, providing a diagnosis for these otherwise unsolved patients.
authors.affiliation: Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.|Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Kristin D
authors.initials: KD
authors.lastname: Kernohan
authors.affiliation: Department of Pathology, Stanford University, Stanford, California.
authors.forename: Laure
authors.initials: L
authors.lastname: Frésard
authors.affiliation: Department of Pathology, Stanford University, Stanford, California.|Department of Genetics, Stanford University, Stanford, California.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Zappala
authors.affiliation: Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Taila
authors.initials: T
authors.lastname: Hartley
authors.affiliation: Department of Pathology, Stanford University, Stanford, California.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Smith
authors.affiliation: Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Justin
authors.initials: J
authors.lastname: Wagner
authors.affiliation: Department of BMI, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Xu
authors.affiliation: Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Arran
authors.initials: A
authors.lastname: McBride
authors.affiliation: Division of Neurology, The Ottawa Hospital, Ottawa, Ontario, Canada.
authors.forename: Pierre R
authors.initials: PR
authors.lastname: Bourque
authors.affiliation: Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Care Rare Canada
authors.initials: CRC
authors.lastname: Consortium
authors.affiliation: Department of BMI, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Steffany A L
authors.initials: SAL
authors.lastname: Bennett
authors.affiliation: Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.|Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Dyment
authors.affiliation: Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.|Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Kym M
authors.initials: KM
authors.lastname: Boycott
authors.affiliation: Department of Pathology, Stanford University, Stanford, California.|Department of Genetics, Stanford University, Stanford, California.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Montgomery
authors.affiliation: Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.|Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.|Division of Neurology, The Ottawa Hospital, Ottawa, Ontario, Canada.|Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.|Centre for Neuromuscular Disease (CNMD), University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Jodi
authors.initials: J
authors.lastname: Warman Chardon
mesh_terms: D055573:Acid Ceramidase / Q000097:blood / Q000235:genetics*; D002675:Child, Preschool; D006801:Humans; D008297:Male; D009134:Muscular Atrophy, Spinal / Q000097:blood* / Q000150:complications / Q000235:genetics; D009154:Mutation; D020191:Myoclonic Epilepsies, Progressive / Q000097:blood* / Q000150:complications / Q000235:genetics; D057089:Pathology, Molecular; D012326:RNA Splicing / Q000235:genetics*; D017422:Sequence Analysis, DNA; D059467:Transcriptome / Q000235:genetics
chemical_list: C526693:ASAH1 protein, human; D055573:Acid Ceramidase
keywords: ASAH1; next-generation sequencing; spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME); transcriptome sequencing
  