We report the identification of a novel 12 bp deletion of the pre‐mRNA splicing gene PRPF31 in a large Chinese family with autosomal dominant retinitis pigmentosa (adRP). This mutation results in the deletion of four amino acids (ΔH₁₁₁K₁₁₂F₁₁₃I₁₁₄) including H₁₁₁, an amino acid residue that is highly conserved throughout evolution. The 12 bp deletion co‐segregates with the disease phenotype in 19 RP patients in the family, but is not present in unaffected relatives or 100 normal individuals. Our data indicate that the novel 12 bp deletion in PRPF31 causes retinitis pigementosa in this Chinese adRP family. In contrast to the incomplete penetrance observed in most adRP families linked to chromosome band 19q13.4 (RP11), the 12 bp PRPF31 deletion identified in this study appears to show high penetrance. These data expand the spectrum of PRPF31 mutations causing adRP, and confirm the role of PRPF31 in the pathogenesis of RP. © 2003 Wiley‐Liss, Inc.