In response to Gulcin Akinci’s and Haluk Topaloglu's letter regarding our article “Predictors of loss of ambulation in Duchenne muscular dystrophy: A systematic review and meta-analysis”

We thank Dr Gulcin Akinci and Dr Haluk Topaloglu for their comments ¹ on our literature review. ² The concern is that current evidence supports that deletions amenable to exon 53 skipping are not associated with later loss of ambulation (LoA) compared with other deletions in DMD. Certainly, we did mention this in the Results section (DMD mutations and genetic modifiers) and in Table 2. We stated that Servais et al. ³ found that the mean age at LoA was estimated at 8.7 years for participants with exon 53 skip-amenable mutations, compared with 10.4 for those with mutations not treatable by exon 53 skipping (p = 0.031), and 10.7 years for those with deletions not treatable by exon 53 skipping (p = 0.011), suggesting that deletions amenable to exon 53 skipping are associated with earlier LoA compared to other deletions in DMD. However, we believe that the confusion arises from an unforeseen error in the summary of the evidence in the Discussion section (as well as Figure 4 and Figure 5), where we indeed erroneously stated that mutations amenable to exon 53 skipping are associated with later LoA. This mistake has been corrected in an Erratum ⁴ to the published article.

It is worth noting that two publications mentioned by Dr Gulcin Akinci and Dr Haluk Topaloglu were not included in our SLR as they did not meet the inclusion criteria (the first article ⁵ did not report results for LoA as an outcome, and the second ⁶ was published after our search period).

We are grateful that this mistake was brought to our attention and thank Dr Gulcin Akinci and Dr Haluk Topaloglu again for their letter.