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Most pathogenic DMD variants are detectable and interpretable by standard genetic testing for dystrophinopthies. However, approximately 1∼3% of dystrophinopthies patients still do not have a detectable DMD variant after standard genetic testing, most likely due to structural chromosome rearrangements and/or deep intronic pseudoexon-activating variants. Here, we report on a boy with a suspected diagnosis of Becker muscular dystrophy (BMD) who remained without a detectable DMD variant after exonic DNA-based standard genetic testing. Dystrophin mRNA studies and genomic Sanger sequencing were performed in the boy, followed by in silico splicing analyses. We successfully detected a novel deep intronic disease-causing variant in the DMD gene (c.2380 + 3317A > T), which consequently resulting in a new dystrophin pseudoexon activation through the enhancement of a cryptic donor splice site. The patient was therefore genetically diagnosed with BMD. Our case report further emphasizes the significant role of disease-causing splicing variants within deep intronic regions in genetically undiagnosed dystrophinopathies.

Shear thickening fluids (STFs) can effectively enhance the ballistic performance of Kevlar. Considering that the unique shear thickening effect of STF is the key factor to enhance the impact resistance of fabrics, this study sought to reveal the impact resistance mechanism of STF-Kevlar and guide its further design by using a numerical simulation method of fluid–structure interaction. The ballistic limits of neat Kevlar and STF-Kevlar in the ballistic tests were 55.14 m/s and 72.40 m/s, respectively, and the simulation predictions were 55.58 m/s and 70.40 m/s, which indicated that the established finite element model has high accuracy for predicting the ballistic performance curve of the fabric. The results of numerical simulation showed that STF-Kevlar has smaller deformation during the impact process than neat Kevlar. Due to the strengthening effect of STF, the resistance of STF-Kevlar to the elastomer was greater than that of neat fabric. With the increase of the impact velocity, the STF-Kevlar increasingly relied on STF to absorb energy. In engineering practice, through the fluid–structure interaction numerical simulation method, the prediction of the ballistic performance of the composite fabric can be realized in the early stage of manufacture, and guide further design and optimization.