Craniometaphyseal dysplasia

Craniometaphyseal dysplasia is a rare condition characterized by thickening (overgrowth) of bones in the skull (cranium) and abnormalities in a region at the end of long bones known as the metaphysis. The abnormal bone growth continues throughout life. Except in the most severe cases, the lifespan of people with craniometaphyseal dysplasia is normal.

Bone overgrowth in the head causes many of the signs and symptoms of craniometaphyseal dysplasia. Affected individuals typically have distinctive facial features such as a wide nasal bridge, a prominent forehead, wide-set eyes (hypertelorism), and a prominent jaw. Excess bone formation in the jaw can delay teething (dentition) or result in absent (non-erupting) teeth. Infants with craniometaphyseal dysplasia may have breathing or feeding problems caused by narrow nasal passages. In severe cases, abnormal bone growth can pinch (compress) the nerves that extend from the brain to various areas of the head and neck (cranial nerves). Compression of the cranial nerves can lead to paralyzed facial muscles (facial nerve palsy), blindness, or deafness.

The x-rays of individuals with craniometaphyseal dysplasia show unusually shaped long bones, particularly long bones in the legs. The ends of these bones are wider and appear less dense than usual in people with this condition.

There are two types of craniometaphyseal dysplasia, which are distinguished by their pattern of inheritance and genetic cause. They are known as the autosomal dominant and autosomal recessive types.