Cleidocranial dysplasia (CCD) is a rare genetic condition that affects how bones and teeth develop throughout the body. It occurs in roughly 1 per million people worldwide. The name itself describes two of its hallmark features: “cleido” refers to the clavicles (collarbones), which are underdeveloped or absent, and “cranial” refers to the skull, where the soft spots present at birth stay open much longer than usual. Despite these skeletal differences, most people with CCD have a normal life expectancy.
What Causes It
CCD is caused by a mutation in the RUNX2 gene, which acts as a master regulator of bone formation. This gene tells the body how to produce the cells responsible for building bone tissue. When the gene is mutated, bones throughout the skeleton form more slowly or incompletely, especially bones that develop through a process called membrane ossification, which includes the skull and collarbones.
The condition follows an autosomal dominant inheritance pattern, meaning a child only needs one copy of the mutated gene (from one parent) to be affected. A parent with CCD has a 50% chance of passing it on with each pregnancy. However, a significant number of cases arise from new, spontaneous mutations, meaning neither parent carries the gene change. Genetic testing can confirm the diagnosis by identifying a RUNX2 mutation.
How It Affects the Skeleton
The most recognizable feature of CCD involves the collarbones. They can range from partially formed to completely absent. People with missing or very underdeveloped collarbones can often bring their shoulders together in front of their chest, a physical finding that sometimes leads to an initial diagnosis.
The skull is also significantly affected. The soft spots (fontanelles) that are normal in infants may remain open well into childhood or even adulthood, because the flat bones of the skull are slow to fuse. Extra small bone fragments called wormian bones often appear in skull X-rays along the suture lines where skull plates meet.
Beyond the skull and collarbones, CCD affects the pelvis, spine, and limbs. X-rays commonly reveal a narrowed pelvic inlet, widened joints at the base of the spine, and an abnormal angle where the thighbone meets the hip (a condition called coxa vara, where the angle drops below 120 degrees). The rib cage tends to be small and cone-shaped with short, oblique ribs, which can make individuals more susceptible to chest infections. Adults with CCD are typically shorter than average.
Dental Problems Are a Major Feature
For many people living with CCD, the dental issues end up being the most disruptive part of the condition. Baby teeth often don’t fall out on their own because the permanent teeth beneath them fail to erupt normally. On top of that, extra teeth (called supernumerary teeth) grow in the jawbone. Studies have documented anywhere from zero to 18 extra teeth in CCD patients, and these surplus teeth crowd the jaw and block permanent teeth from coming in.
Managing the dental complications is a long process that typically begins in childhood and extends into early adulthood. The general approach involves removing retained baby teeth and extra teeth surgically, then exposing the impacted permanent teeth so they can be guided into place with orthodontic treatment. In some cases, jaw surgery and dental implants are needed later to achieve a functional bite. Several well-established treatment protocols exist, and the specific plan depends on the severity of the dental involvement and the patient’s age when treatment begins.
Hearing, Sinus, and Airway Complications
About 39% of people with CCD develop conductive hearing loss, meaning sound has trouble traveling through the outer or middle ear to reach the inner ear. This is largely driven by recurrent ear infections, which are common at any age in CCD. The same structural differences that affect the skull and facial bones also make sinus infections more frequent and can contribute to upper airway obstruction.
Ear tubes are a common intervention for children with repeated middle ear infections, and regular hearing assessments help catch any loss early. Staying current on vaccinations, including the annual flu shot, is particularly important because respiratory infections can be harder to clear and more likely to cause complications.
How It’s Diagnosed
CCD is usually suspected based on physical features and confirmed through imaging and genetic testing. A chest X-ray may reveal absent or underdeveloped collarbones, a narrow, cone-shaped rib cage, or spinal curvature. A pelvic X-ray often shows the characteristic widened joints and abnormal hip angles. Dental X-rays reveal the crowded mix of retained baby teeth, impacted permanent teeth, and supernumerary teeth that is nearly unique to CCD.
Genetic testing for RUNX2 mutations provides a definitive diagnosis and can also be used for family planning purposes, since the condition can be passed to future generations.
Living With CCD
Because CCD affects so many body systems, care typically involves a team of specialists. A 2025 Delphi panel of 13 experts from institutions including Johns Hopkins, the University of Minnesota, and Hadassah Medical Center reached consensus on 37 standard-of-care recommendations spanning diagnosis, dental and orthodontic management, orthopedic care, endocrine monitoring, and ENT follow-up. The practical takeaway: people with CCD benefit from coordinated care rather than seeing each specialist in isolation.
Orthopedic monitoring tracks bone density, hip alignment, and any spinal changes over time. Dental care is the longest active treatment arc, often requiring multiple surgical and orthodontic phases from childhood through the late teens or early twenties. Hearing screenings, sinus management, and airway assessments round out the picture. With consistent multidisciplinary care, most individuals with CCD lead full, active lives, though the dental and orthopedic management requires patience and planning.