Spondyloepiphyseal dysplasia tarda, Kohn type

Definition

A rare spondyloepiphyseal dysplasia and spondyloepimetaphyseal dysplasia characterized by short trunk dwarfism, progressive involvement of the spine and epiphyses and mild-to-moderate intellectual deficiency. Typical radiographic features include platyspondyly, abnormal lumbar vertebral bodies with anterior tongue-like protrusions, and the presence of degenerative large joint changes in the shoulder, hip and knee joints manifesting as narrowing of the joint spaces and irregularities of the articulate surfaces. Dens epistropheus may be absent. There have been no further descriptions in the literature since 1987.