Craniometaphyseal Dysplasia Autosomal Dominant is a disorder is a rare skeletal disorder that results from a heterozygous mutation in human homologous of progress in ankylosis gene (ANKH). Abnormal bone overgrowth occurs from the beginning of a child's life as well as throughout their lifetime resulting in the narrowing of the cranial formania.This leads to cranial nerve and facial features compression. In addition, this disorder is located on the 5p chomsome.
The mutation in ANKH gene causes a decrease in the to transport pyrophosphate out of cells. Pyrophosphate regulates bone formation by preventing mineralization. The ANKH gene provides instructions for making a protein present in the bones. Only one mutated ANKH gene can cause autosomal dominant Craniometahyseal Dysplasia.
This autosomal dominant disorder is inherited in and autosomal dominant manner and is caused by a pathogenic variant in ANKH. If one parent has this disorder then there is fifty percent chance of them having a child with the disorder as well. Yet it can also be a single occurrence in a family also known as de novo. Through time the disorder can seem to go away on its own due to it becoming less noticeable as the child grows. People who are affected by this disorder are young children and infants.
This disorder can lead to blindness. Some effects it has on the body are:
- facial palsy
- paranasal bossing
- wide set eyes
- delay teething
- thickening of bones in the skull
- sclerosis of alveolar bone
- abnormal growth
Craniometaphyseal Dysplasia Autosomal Dominant is diagnosed based on clinical and radiographic findings that include hyperostosis. Some things such as cranial base sclerosis and nasal sinuses obstruction can be seen during the beginning of the child's life. In radiographic findings the most common thing that will be found is the narrowing of foramen magnum and the widening of long bones. Once spotted treatment is soon suggested to prevent further compression of the foramen magnum and disabling conditions.
The only treatment for this disorder is surgery, Craniofacial Surgery. The surgery would reduce the compression of cranial nerves and spinal cord. However, bone regrowth is common since the surgical procedure can be technically difficult. Genetic counseling is offered to the families of the people with this disorder. There they will learn about the causes and effects of the disease as well as treatment.