A class of small molecule drugs, in particular one named ataluren (also known as Translarna), can bind to the protein-making machinery within the cell (the ribosome) and weaken its ability to detect abnormal stop signals resulting from
nonsense mutations. The ribosome is involved in translation of a protein by reading the transcribed instruction part of the gene (also known as the messenger RNA, mRNA or transcript) and detecting the sequence of three letter codes (codon) to join amino acids together to form a protein.
A variety of RUNX1 mutations have been described, including frameshift or
nonsense mutations or deletion throughout the gene as well as missense point mutations clustering within the highly conserved RUNT homology domain (RHD) and transactivation domain (TAD).
We have identified via WES a previously reported
nonsense mutation c.4802C>G located in exon 22 of the ASPM gene transcript 1 (NM_018136) in both families.
(NASDAQ: PTCT) has received preliminary data from the first international drug registry for Duchenne patients receiving Translarna (ataluren), underscoring the long-term clinical benefit of Translarna when used in routine clinical practice in delaying irreversible muscle loss in children with Duchenne caused by a
nonsense mutation, when compared with published natural history, the company said.
To the best of our knowledge, this mutation is a novel, previously undetected, pathogenic
nonsense mutation, associated with severe, classical IOPD with a good response to ERT (Database: www.pompecenter.nl).
WES revealed a previously identified
nonsense mutation c.[2041C>T]; p.[R681*] found in exon 14, but in heterozygous form in the proband, which did not segregate with the phenotype in the family.
The 28 novel mutations included 22 missense mutations, 3 small insertions, 1 splicing mutation, 1 small deletion, and 1
nonsense mutation. Among these novel mutations, the mutation c.1130_1132delTCT caused a three base pair deletion in ARSA, while the mutation c.954G>A, pTrp318Term produced a premature termination code, the mutations c.1344_1345insCC, c.302_303insG, and c.1428_1429insC caused one or two base pair insertion in ARSA, and the mutations c.1108-20A>G, c.465G>A (p.Lys125ProfsX17), and IVS3+2T>C led to splicing and amino acid changes in the protein.
Whole exome sequencing revealed a
nonsense mutation in exon 7 of the DTNA gene (C601T).
A
nonsense mutation in Exon 1 (c.31C>T) changes an arginine (R) codon (CGA) into a translation termination (X) codon (TGA) at amino acid position 11 (p.ArgllTer).