Classic X-linked spondyloepiphyseal dysplasia tarda in a woman with normal karyotype.

A case of classic X-linked SED tarda in a woman with normal karyotype is described. The clinical and radiological findings left no doubts about the diagnosis of classical SED tarda (X-linked). The most probable hypothesis for explaining the clinical manifestation of this pathology in a woman with normal karyotype is random inactivation of all X chromosomes with the normal allele in her cells.