CMD can be inherited in an autosomal dominant or recessive trait. CMD may also be caused by de novo mutations. The goal of this study is to identify genes and regulatory elements on chromosomes that are the cause for CMD. The investigators also study blood samples and tissue samples from patients to learn about the processes that lead to this disorder. The investigators long-term goal is to find mechanisms to slow down bone deposition in CMD patients.

CMD is a very rare bone disorder that affects mostly bones of the head (=cranial bones) but also long (=tubular) bones. Therefore, CMD has been added to the class of craniotubular bone disorders. There are a number of disorders in this group and sometimes they are difficult to distinguish. Typical signs for CMD are the lifelong bone deposition in bones of the face and head (=progressive craniofacial hyperostosis) and the widening of the ends of long bones (=metaphyseal flaring). Typical facial characteristics are wide-set eyes and a prominent jaw (=mandible). CMD is sometimes diagnosed in infants. The best way to confirm diagnosis is by molecular genetics.

Inclusion Criteria:

• CMD; unaffected individuals only if part of a participating CMD family

Exclusion Criteria:

• No CMD; unaffected individuals only as part of a participating CMD family

Individuals with diagnosed CMD