Inflammatory peeling skin syndrome caused by homozygous genomic deletion in the PSORS1 region encompassing the CDSN gene

Abstract Peeling skin syndrome ( PSS ) type B is a rare recessive genodermatosis characterized by lifelong widespread, reddish peeling of the skin with pruritus. The disease is caused by small‐scale mutations in the C orneodesmosin gene ( CDSN ) leading to premature termination codons. We report for the first time a J apanese case resulting from complete deletion of CDSN . Corneodesmosin was undetectable in the epidermis, and CDSN was unamplifiable by PCR . QMPSF analysis demonstrated deletion of CDSN exons inherited from each parent. Deletion mapping using microsatellite haplotyping, CGH array and PCR analysis established that the genomic deletion spanned 49–72 kb between HCG 22 and TCF 19, removing CDSN as well as five other genes within the psoriasis susceptibility region 1 ( PSORS 1) on 6p21.33. This observation widens the spectrum of molecular defects underlying PSS type B and shows that loss of these five genes from the PSORS 1 region does not result in an additional cutaneous phenotype.