Allele-specific knockdown using siRNA has been reported to efficiently and selectively silence the mutant mRNA transcripts in UCMD with dominant mutations in COL6 genes, such as the heterozygous exon 16 deletion in the COL6A3 gene,15 and the missense c.850G > A (p.G284R) mutation in the COL6A1 gene.16 The gene discussed is COL6A1; the disease is Congenital muscular dystrophy, Ullrich type.