We have studied the efficacy and the prognostic impact of novel agents in 50 primary plasma cell leukemia (pPCL) patients registered in our database. Eighty percent of patients were treated upfront with novel agent-based combinations; 40% underwent autologous stem cell transplantation (ASCT). Objective response rate was 76; 38% achieved at least very good partial response (≥vgPR) and this correlated significantly with bortezomib-based therapy plus ASCT. At the time of evaluation, 40 patients had died. Early mortality rate (≤1 month) was 6%. Median progression-free survival (PFS) and overall survival (OS) were 12 months and 18 months respectively, both significantly longer in patients treated with bortezomib-based therapy + ASCT vs. others (PFS: 18 vs. 9 months; p = 0.004, OS: 48 vs. 14 months; p = 0.007). Bortezomib-based therapy + ASCT predicted for OS in univariate analysis. In multivariate analysis, achievement of ≥vgPR and LDH ≥ 300 U/L were significant predictors for OS. These real-world data, based on one of the largest reported national multicenter series of pPCL patients treated mostly with novel agents support that, among the currently approved induction therapies, bortezomib-based regimens are highly effective and reduce the rate of early mortality whereas in combination with ASCT consolidation they prolong OS.
Background
Mutations in the GBA gene that encodes the lysosomal enzyme acid β‐glucocerebrosidase cause Gaucher disease (GD), the most common lysosomal storage disorder. Most of the mutations are missense/nonsense, however, a few splicing mutations within or close to conserved consensus donor or acceptor splice sites have also been described. The aim of the study was to identify the mutation(s) in a Cypriot patient with type I GD.
Methods
The genomic DNA of the proband was screened for nine common mutations using Polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis. All exons and exon‐intron boundaries, and the 5’UTR and 3’UTR regions of the GBA gene, were investigated by Sanger sequencing. RNA analysis was performed using standard procedures, and the abnormal transcript was further cloned into pGEM‐T‐Easy plasmid vector and sequenced. The relevant intronic region was further sequenced by the Sanger method to identify the genetic variant.
Results
A novel point mutation, g.12599C > A (c.999 + 242C > A), was detected deep in intron 7 of the GBA gene. This type of mutation has been previously described for other diseases but this is the first time, as far as we know, that it is described for GD. This mutation creates a new donor splice site leading to aberrant splicing and resulting in the insertion of the first 239nt of intron 7 as a pseudoexon in the mRNA, creating a premature stop codon.
Conclusion
This study expands the mutation spectrum of GD and highlights the importance of RNA sequencing for the molecular diagnosis of patients bearing mutations in nonexonic regions.
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