Craniodiaphyseal dysplasia is an unusual genetic disorder in which calcium builds up excessively in the bones, causing extreme thickening and hardness. It is progressive, and typically becomes fatal in childhood because it interferes so severely with neurological function. Treatment options are available to manage craniodiaphyseal dysplasia, including surgery and medications to improve quality of life. Also known as lionitis, the condition appears to be recessive, and very few cases have been described, which makes determining genetic links difficult.
Some of the most marked features of this disease appear in the skull and face. As the skull thickens, the facial features can distort, and the patient’s face may become rounded and elongated. Within the skull, the series of holes known as foramina which provide openings for nerves, blood vessels, and ligaments begin to narrow. Initially this may cause problems like recurrent sinus infections because of poor drainage.
Over time, neurological symptoms can develop because the narrowing foramina start to compress the patient’s nerves. Blindness and deafness can occur, and patients may develop partial or total paralysis due to compression of the spinal cord. A doctor may recommend surgery for decompression, but the craniodiaphyseal dysplasia can replace the removed bone after the surgery, and the problem can reoccur. Surgery can also carry significant risks, as it may involve delicate structures.
The rest of the body can also develop signs of craniodiaphyseal dysplasia. Growth plates at the ends of the long bones may begin to thicken and harden too early. On an x-ray, it can be possible to see areas of unusual bone density, showing areas where calcium is building up excessively and large numbers of osteoblasts, the cells that make new bone, are present. Eventually, the thickening can outstrip available treatments and the patient may die due to nerve and blood vessel compression.
This skeletal disorder is highly unusual, and is not typically considered in young patients who present with skeletal abnormalities. As the condition progresses, a diagnosis of craniodiaphyseal dysplasia can become more evident, because it may be the only condition that truly fits the symptoms. The extreme rarity of the condition can make it a topic of interest for specialists, who may be able to offer suggestions for management and treatment that take advantage of new medications and surgical techniques. As of 2011, little was known about the disorder and prenatal diagnostic testing was not available or considered a high priority due to the low incidence of the condition.