Historical evidence for the genetic heterogeneity of pseudoxanthoma elasticum

Re-examination of published data from affected families with pseudoxanthoma elasticum (PXE) described in the literature between 1896 and 1968 supported the concept of clinical and genetic heterogeneity. There was clinical evidence for two autosomal dominant and one recessive type, although only a single patient with recessive type II was described. Examination of the individual pedigrees supported both autosomal dominant and recessive patterns of inheritance. The pooled genetic data were less helpful because they were so highly selected. (They had been reported in the literature.) Even so the dominant type II data fitted the hypothesis, whilst the type I and recessive groups were near the expected values. The clinical properties of the groups corresponded closely to the recent British (Pope, 1973) survey. In general, the dominant type I group showed classical cutaneous changes, vascular complications were common and the chief ophthalmic complication was a severe choroidoretinitis. The dominant type II group, in contrast, has an atypical macular rash, or sometimes no rash at all, no vascular complications and very mild retinal changes. Choroidoretinitis was rare and peau d'orange patterns and prominent choroidal vessels common. The recessive group was of intermediate severity.