OBJECTIVETo investigate the mutation spectrum of phosphodiesterase beta subunit (PDE6B) gene and incidence in Chinese retinitis pigmentosa (RP) patients.

METHODSGenomic DNA was extracted from the blood samples of 38 patients from 35 autosomal recessive retinitis pigmentosa (ARRP) families and 55 sporadic cases. The mutation of the PDE6B gene was detected using PCR-SSCP, and the amplified PCR product of abnormal bands was sequenced.

RESULTSWithin intron 10 of PDE6B gene, a mutation was found in an ARRP family, a G --> A transition at 19th base upstream 5'-end of exon 11. A novel complex heterozygous variant of PDE6B gene in a sporadic case, a T to C transition in codon 323 resulting in the substitution of Gly by Ser and two bp(TG) inserted between the 27th-28th bp upstream of the 5'-end of exon 10 were both present in the same isolate RP. But they were not found in 100 unrelated normal individuals. A sporadic RP was found carrying a sequence variant of PDE6B gene, a G to C transversion in intron 18, the 15th base adjacent to the 3'end of exon 18. Another isolate RP was found to have 2 bp inserted between 31st and 32nd base upstream 5'end of exon 4 (in intron 3) of PDE6B gene.

CONCLUSIONThere is a complex heterozygous mutation of PDE6B gene responsible for a sporadic RP patient in China. Several DNA variants were found in intron of PDE6B gene in the national population.