Craniometaphyseal dysplasia: An inherited skeletal condition that involves abnormal bone formation and abnormal mineralization of the skull as well as the long bones. There is increased density of craniofacial bones beginning at the base of the skull during early childhood. The progressive thickening of the bones of the skull can lead to severe visual and neurological impairment, such as facial palsy and deafness. Typical facial features include a wide bridge of the nose and wide spacing of the eyes. The growth plates (metaphyses) of long bones are widened (Erlenmeyer flask-shaped) and show decreased density while the shafts of the long bones are thickened.
Craniometaphyseal dysplasia occurs in autosomal dominant and recessive forms. The dominant form due to one copy of the gene is more common and less severe. The gene in chromosome region 5p15.2-p14.1 is the ANK gene which encodes a protein involved in the transport of pyrophosphate into the bone matrix. Pyrophosphate levels are critical for the regulation of bone mineralization. The gene for the recessive form is in a different location, in chromosome region 6q21-22. Its function is not yet known.
- Craniopagus parasiticus
Craniopagus parasiticus: Conjoined twins joined at the head (craniopagus) in which a rudimentary head (with little or no body) is attached to the head of the larger and usually more normal twin. The rudimentary head was thought to be parasitic.
Craniopharyngioma: A benign brain tumor that develops from embryonic tissue that forms part of the pituitary gland. Pressure on the pituitary gland by the tumor reduces the availability of the hormone vasopressin, raising the pressure within the cranium. A craniopharyngioma usually includes hard, calcified components within the tumor itself and affects the development of the […]
Craniosynostosis: Premature fusion of the sutures between the growth plates in an infant’s skull that prevents normal skull expansion. Craniosynostosis can cause an abnormally shaped skull. Premature closure of all the sutures can cause microcephaly (an abnormally small head), which prevents the normal growth of the brain and results in mental retardation. Treatment usually involves […]
Craniotomy: A surgical operation in which an opening is made in the skull.
Cranium: The top portion of the skull, which protects the brain. The cranium includes the frontal, parietal, occipital, temporal, sphenoid, and ethmoid bones.