PuSH - Publication Server of Helmholtz Zentrum München

Stalke, A.* ; Pfister, E.D.* ; Baumann, U.* ; Eilers, M.* ; Schäffer, V.* ; Illig, T.* ; Auber, B.* ; Schlegelberger, B.* ; Brackmann, R.* ; Prokisch, H. ; Krooss, S.* ; Bohne, J.* ; Skawran, B.*

Homozygous frame shift variant in ATP7B exon 1 leads to bypass of nonsense-mediated mRNA decay and to a protein capable of copper export.

Eur. J. Hum. Genet. 27, 879-887 (2019)
Publ. Version/Full Text Preprint Research data DOI
Open Access Green as soon as Postprint is submitted to ZB.
Wilson disease (WD) is an autosomal recessive disease of copper excess due to pathogenic variants in the ATP7B gene coding for a copper-transporting ATPase. We present a 5-year-old girl with the homozygous frame shift variant NM_000053.3: c.19_20del in exon 1 of ATP7B (consecutive exon numbering with c.1 as first nucleotide of exon 1), detected by whole-exome sequencing as a secondary finding. The variant leads to a premature termination codon in exon 2. The girl exhibited no WD symptoms and no abnormalities in liver biopsy. ATP7B liver mRNA expression was comparable to healthy controls suggesting that nonsense-mediated mRNA decay (NMD) could be bypassed by the mechanism of translation reinitiation. To verify this hypothesis, a CMV-driven ATP7B minigene (pcDNA3) was equipped with the authentic ATP7B 5' untranslated region and a truncated intron 2. We introduced c.19_20del by site-directed mutagenesis and overexpressed the constructs in HEK293T cells. We analyzed ATP7B expression by qRT-PCR, northern and western blot, and examined protein function by copper export capacity assays. Northern blot, qRT-PCR, and western blot revealed that c.19_20del ATP7B mRNA and protein is expressed in size and amount comparable to wild-type. Copper export capacity was also comparable to wild-type. Our results indicate that c.19_20del in ATP7B is able to bypass NMD by translation reinitiation, demonstrating that the classification of truncating variants as pathogenic without additional investigations should be done carefully.
Additional Metrics?
Edit extra informations Login
Publication type Article: Journal article
Document type Scientific Article
Keywords Wilson-disease; Medical Genetics; American-college; Deficiency; Expression; Mutations; Sequence; Update; Golgi
ISSN (print) / ISBN 1018-4813
e-ISSN 1476-5438
Quellenangaben Volume: 27, Issue: 6, Pages: 879-887 Article Number: , Supplement: ,
Publisher Nature Publishing Group
Publishing Place Macmillan Building, 4 Crinan St, London N1 9xw, England
Reviewing status Peer reviewed