Exploring the utility of whole-exome sequencing as a diagnostic tool in a child with atypical episodic muscle weakness.

TitleExploring the utility of whole-exome sequencing as a diagnostic tool in a child with atypical episodic muscle weakness.
Publication TypeJournal Article
Year of Publication2013
AuthorsHanchard, NA, Murdock, DR, Magoulas, PL, Bainbridge, M, Muzny, D, Wu, Y, Wang, M, Lupski, JR, Gibbs, RA, Brown, CW
JournalClin Genet
Date Published2013 May
KeywordsBase Sequence, Calcium Channels, Child, Preschool, Exome, Exons, Female, Genotype, High-Throughput Nucleotide Sequencing, Humans, Male, Muscle Weakness, Mutation, NAV1.4 Voltage-Gated Sodium Channel, Pedigree, Phenotype

The advent of whole-exome next-generation sequencing (WES) has been pivotal for the molecular characterization of Mendelian disease; however, the clinical applicability of WES has remained relatively unexplored. We describe our exploration of WES as a diagnostic tool in a 3½-year old female patient with a 2-year history of episodic muscle weakness and paroxysmal dystonia who presented following a previous extensive but unrevealing diagnostic work-up. WES was performed on the proband and her two parents. Parental exome data was used to filter potential de novo genomic events in the proband and suspected variants were confirmed using di-deoxy sequencing. WES revealed a de novo non-synonymous mutation in exon 21 of the calcium channel gene CACNA1S that has been previously reported in a single patient as a rare cause of atypical hypokalemic periodic paralysis. This was unexpected, as the proband's original differential diagnosis had included hypokalemic periodic paralysis, but clinical and laboratory features were equivocal, and standard clinical molecular testing for hypokalemic periodic paralysis and related disorders was negative. This report highlights the potential diagnostic utility of WES in clinical practice, with implications for the approach to similar diagnostic dilemmas in the future.

Alternate JournalClin. Genet.
PubMed ID22901280
PubMed Central IDPMC3926310
Grant ListU54 HG003273 / HG / NHGRI NIH HHS / United States
2-U54HG003273-09 / HG / NHGRI NIH HHS / United States