The condition is most commonly diagnosed by physical examination. The abnormally shaped skull, commonly with unusual ridging, can often be detected in the postnatal period. Imaging studies such as CT and X-rays may be needed to confirm the diagnosis, but they may often not be needed.
Less commonly, the condition can be gene-linked, or caused by metabolic diseases, such as rickets or an overactive thyroid. Some cases are associated with other disorders such as an abnormally small head (microcephaly) and excessive accumulation of cerebrospinal fluid in the brain (hydrocephalus).