A homozygous deletion of exon 1 in WISP3 causes progressive pseudorheumatoid dysplasia in two siblings

Progressive pseudorheumatoid dysplasia (PPD) is a rare autosomal recessive disease that causes progressive joint stiffness and pain. It is associated with loss-of-function mutations in the WISP3 gene. We describe two sisters suffering from PPD in whom molecular genetic analysis revealed a homozygous deletion of exon 1 and of the 5'UTR of the WISP3 gene. This is the first time that a gross deletion has been described as the causal mutation in PPD.status: publishe