a group of conditions characterized by growth deficiency of the vertebral column with flattening of the vertebrae or platyspondyly, lack of ossification of the epiphyses, short-trunk dwarfism with limb shortening, and sometimes with other malformations; autosomal dominant [MIM*183900 and MIM*184100], autosomal recessive [MIM*208230 and MIM*271600], and X-linked recessive [MIM*313400] inheritance have been described.