Inherited peripheral neuropathies are a genetically heterogeneous group of disorders characterized by distal muscle weakness and sensory loss. Mutations in genes encoding aminoacyl-tRNA synthetases have been implicated in peripheral neuropathies, suggesting that these tRNA charging enzymes are uniquely important for the peripheral nerve. Recently, a mutation in histidyl-tRNA synthetase (HARS) was identified in a single patient with a late-onset, sensory-predominant peripheral neuropathy; however, the genetic evidence was lacking, making the significance of the finding unclear. Here, we present clinical, genetic, and functional data that implicate HARS mutations in inherited peripheral neuropathies. The associated phenotypic spectrum is broad and encompasses axonal and demyelinating motor and sensory neuropathies, including four young patients presenting with pure motor axonal neuropathy. Genome-wide linkage studies in combination with whole-exome and conventional sequencing revealed four distinct and previously unreported heterozygous HARS mutations segregating with autosomal dominant peripheral neuropathy in four unrelated families (p.Thr132Ile, p.Pro134His, p.Asp175Glu and p.Asp364Tyr). All mutations cause a loss of function in yeast complementation assays, and p.Asp364Tyr is dominantly neurotoxic in a Caenorhabditis elegans model. This study demonstrates the role of HARS mutations in peripheral neuropathy and expands the genetic and clinical spectrum of aminoacyl-tRNA synthetase-related human disease.
- MeSH
- Charcotova-Marieova-Toothova nemoc genetika MeSH
- dědičné senzorické a autonomní neuropatie genetika MeSH
- genetická vazba genetika MeSH
- histidin-tRNA-ligasa genetika MeSH
- lidé MeSH
- mutace genetika MeSH
- nemoci periferního nervového systému genetika MeSH
- rodokmen MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Deep intronic mutations are often ignored as possible causes of human diseases. A deep intronic mutation in the MTRR gene, c.903+469T>C, is the most frequent mutation causing the cblE type of homocystinuria. It is well known to be associated with pre-mRNA mis-splicing, resulting in pseudoexon inclusion; however, the pathological mechanism remains unknown. We used minigenes to demonstrate that this mutation is the direct cause of MTRR pseudoexon inclusion, and that the pseudoexon is normally not recognized due to a suboptimal 5' splice site. Within the pseudoexon we identified an exonic splicing enhancer (ESE), which is activated by the mutation. Cotransfection and siRNA experiments showed that pseudoexon inclusion depends on the cellular amounts of SF2/ASF and in vitro RNA-binding assays showed dramatically increased SF2/ASF binding to the mutant MTRR ESE. The mutant MTRR ESE sequence is identical to an ESE of the alternatively spliced MST1R proto-oncogene, which suggests that this ESE could be frequently involved in splicing regulation. Our study conclusively demonstrates that an intronic single nucleotide change is sufficient to cause pseudoexon activation via creation of a functional ESE, which binds a specific splicing factor. We suggest that this mechanism may cause genetic disease much more frequently than previously reported.
- MeSH
- Cercopithecus aethiops MeSH
- COS buňky MeSH
- exony genetika MeSH
- ferredoxin-NADP-reduktasa genetika MeSH
- homocystinurie klasifikace enzymologie genetika MeSH
- introny genetika MeSH
- jaderné proteiny metabolismus MeSH
- messenger RNA genetika metabolismus MeSH
- místa sestřihu RNA genetika MeSH
- molekulární sekvence - údaje MeSH
- mutace genetika MeSH
- mutantní proteiny genetika MeSH
- proteiny vázající RNA metabolismus MeSH
- sekvence nukleotidů MeSH
- sestřih RNA genetika MeSH
- vazba proteinů MeSH
- vitamin B 12 metabolismus MeSH
- výpočetní biologie MeSH
- zesilovače transkripce genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- aminokyseliny sírové metabolismus MeSH
- dospělí MeSH
- homocystein krev metabolismus MeSH
- homocystinurie diagnóza etiologie genetika MeSH
- lidé MeSH
- methionin krev nedostatek MeSH
- mutační analýza DNA MeSH
- polymerázová řetězová reakce MeSH
- prenatální diagnóza metody MeSH
- těhotenství MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- kongresy MeSH
- přehledy MeSH
- srovnávací studie MeSH
