Here, we report a patient with an 8 kb CCTG expansion in intron 1 of the CNBP gene, a mutation characteristic of myotonic dystrophy type 2 (DM2), whose first manifestation was "idiopathic" eosinophilic myositis.
Myotonic dystrophy type 2 (DM2) is an autosomal dominant multisystemic disorder caused by a CCTG expansion in intron 1 of the zinc finger protein 9 gene on chromosome 3.
Myotonic dystrophy type 2 (DM2) is an autosomal dominant, multisystem disorder caused by a CCTG tetranucleotide repeat expansion located in intron 1 of the zinc finger protein 9 gene (ZNF9 gene) on chromosome 3q 21.3.
These results show that [CCTG]n repeat expansion, differently from the DM1 mutation, does not influence the methylation status of the CNBP gene and suggest that other molecular mechanisms are involved in the pathogenesis of DM2.
Expansion of non-coding CTG and CCTG repeats in the 3' UTR of the myotonin protein kinase (DMPK) gene in Myotonic Dystrophy type 1 (DM1) and in the intron 1 of Zinc Finger Protein 9 (ZNF9) in Myotonic Dystrophy type 2 (DM2) represent typical non-coding mutations that cause the diseases mainly through transdominant effect on the RNA metabolism (splicing, translation and RNA stability).
Myotonic dystrophy type 2 (DM2) is an autosomal dominant multisystem disorder caused by CCTG repeat expansions within intron 1 of the ZNF9 gene on chromosome 3q.
The Genea066 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying expansion of CCTG repeats in exon 1 of the ZNF9 gene, indicative of Myotonic Dystrophy Type 2 (DM2).
The recent discovery that an untranslated CCTG expansion causes the same constellation of clinical features in myotonic dystrophy type 2 (DM2), along with other recent discoveries on DM1 pathogenesis, have led to the understanding that both DM1 and DM2 mutations are pathogenic at the RNA level.
However, the discovery that a transcribed but untranslated CCTG expansion causes myotonic dystrophy type 2 (DM2), along with other discoveries on DM1 and DM2 pathogenesis, indicate that the CTG and CCTG expansions are pathogenic at the RNA level.
The mutation responsible for DM1 is a CTG repeat in the 3' UTR of the dystrophia myotonica protein kinase gene (DMPK) on chromosome 19q13.3, while DM2 is caused by an unstable CCTG expansion in intron 1 of the zinc finger protein 9 gene (ZNF9) on chromosome 3q21.3.
The identification and characterization of RNA-binding proteins that interact with expanded CUG repeats and the discovery that a similar transcribed but untranslated CCTG expansion in an intron causes myotonic dystrophy type 2 (DM2) have uncovered a new type of mechanism in which microsatellite expansion mutations cause disease through an RNA gain-of-function mechanism.
Myotonic dystrophy type 2 (DM2) is an autosomal dominant muscular dystrophy caused by the expansion of an intronic tetranucleotide CCTG repeat in CNBP on chromosome 3.
Among them, the thermodynamically less stable TTTA and CCTG MDBs have been proposed to be the structural intermediates that cause TTTA and CCTG repeat expansions during DNA replication in <i>Staphylococcus aureus</i> pathogen and myotonic dystrophy type 2 patients, respectively.