## 3 Discussion  
In this work, we show that the mere presence of a mutation on the _SCNSA_ gene, rather than its precise location within the sodium channel, is a determining factor in the development of BrS. Consistent with previous studies [21], our analysis shows a higher incidence of mutations in the _SCNSA_ gene affecting the transmembrane and pore domains. However, contrary to expectations, the study revealed that the specific location of NaV1.5  
Figure 2: NaV1.5 PTM sites along the NaV1.5 protein channel. Percentage of ordered (OR) and disordered (IDR) regions in NaV1.5 (**A**) predicted to be phosphorylated; (**B**) demonstrated to be phosphorylated; (**C**) predicted to be N- and O-glycosated; (**D**) predicted to be PEST motif; (**E**) predicted to be ubiquitinated. mutations did not lead to significant differences in the clinical presentation of BrS. This result challenges classifications by in silico prediction tools that predominantly classified mutations in IDLs domain as _'benign'_. Furthermore, these findings have important implications for current clinical practice, as patients carrying _SCNSA_ mutations in unstructured portions should not be rashly assured of a benign phenotype. Instead, it appears critical to perform further investigations to ensure appropriate clinical management. The effectiveness of correctly predicting the functional impact of a mutation is clearly influenced by its location, as the tools consider data from resolved protein structures and evolutionary conservation [22]. Indeed, using in silico characterization of IDL domains in the NaV1.5 channel, we found that they are enriched in intrinsically disordered regions (IDRs), which are well established to play a pivotal role in diverse aspects of protein functionality, such as recognition, regulation, and orchestration of numerous signaling events [23]. Considering that IDRs are tightly regulated regions within healthy cells, mutation accumulation in these areas can precipitate disease, as seen in the cases of _P53_[24] and the oncogene _PTEN_[25]. Although some recent studies have examined the IDR of transmembrane proteins and some channel types [19], we show here that NaV1.5 has the highest IDR among the nine homologous members of the voltage-gated sodium channel family. While structural similarity is maintained in the _core_ of NaV, which represents the pore-forming or transmembrane domains, the length and positions of the IDR regions are specific to each IDL domain of the channel, suggesting their primary regulatory functions. In this context, PTMs play a central role in controlling the conformational dynamics of IDLs to interact with target proteins. As a result, the addition of different chemical groups leads to local and global conformational adjustments due to changes in the total energy of a protein [26; 27]. In NaV1.5, phosphorylation and glycosylation make up the bulk of PTMs, arguing for their primary function in modulating the downstream channel cascade and ion flux through the pore channel by specific charges around the protein. Disruption of such essential sites in PTMs could lead to loss of flexibility and docking, ultimately limiting channel properties, as shown by [PERSON] et al. [28], where acquired arrhythmogenic phenotypes were observed after loss of PTMs. However, most studies focus on mutations in folded regions and often neglect mutations in unstructured or disordered regions or even categorize them as variants of unknown significance, despite their common occurrence in disease-associated proteins [29; 30; 31]. As a result, prediction tools that assess the 'pathogenicity' of mutations by analyzing changes in the structural stability of proteins are often unable to make accurate predictions in disordered regions [29; 32]. Indeed, our results provide an opportunity to reevaluate and explain previous observations documented in the literature.