摘要Background:Most mutations in the COL6A3 gene lead to collagen Ⅵ-related myopa-thies.This is due to a reduced expression or mislocalization of the COL6A3 protein.Therefore,studying the consequence of knocking out the Col6a3 gene in mouse mod-els is relevant,but the Col6a3 mouse models reported so far do not entirely abolish COL6A3 protein expression.Methods:Here,we present the development,validation and preliminary phenotypic characterization of a novel CRISPR-based knockout mouse model targeting Col6a3 exon 3(Col6a3d3/d3).Results:In this mouse model,Col6a3 mRNA is still expressed at a similar level to wild-type littermates,although the expected protein is undetectable by mass spec-trometry.Histological analysis of Col6a3d3/d3 quadriceps revealed an abnormally high frequency of muscle cells with internally nucleated muscle cells,consistent with a myopathy phenotype.Interestingly,Col6a3d3/d3 mice are smaller in size,with their fat,muscle,and bone kept proportional compared to wild-type littermates.Conclusions:In summary,we performed the validation and preliminary phenotypic characterization of a novel Col6a3 knockout mouse model that could be further charac-terized and used to study COL6A3 biology and model collagen Ⅵ-associated diseases.