Craniometadiaphyseal dysplasia, wormian bone type is an extremely rare craniotubular bone dysplasia syndrome described in fewer than 10 patients to date. Clinical manifestations include macrocephaly, frontal bossing, malar hypoplasia, prominent mandible and dental hypoplasia. Other skeletal anomalies include abnormal bone modeling in tubular bones, multiple wormian bones and deformities of chest, pelvis and elbows. An increased risk of fractures is noted.

The presence of extra bones within a cranial suture. Wormian bones are irregular isolated bones which appear in addition to the usual centers of ossification of the cranium.