This is the condition that occurs as the result of abnormal head and the face that develops before the birth of the infant. Frontonasal dysplasia is typically characterized by the flat nose and wide-set eyes. There are three types of this disorder that are distinguished by the genetic mutation and the symptoms that vary among the affected individuals. There are only around 100 cases reported in the scientific literature.
Causes
As there are three types of this disorder, accordingly three types of genetic mutations are identified to cause this condition. The mutation in the gene ALX3 causes frontonasal dysplasia 1, ALX4 causes type 2 and ALX1 is responsible for the type 3. These three types of genes are normally responsible for the normal development of the body, particularly the face and the head before the birth. The proteins that are produced by these genes are responsible for the regulation of cellular growth, division and their movement. The mutation in any of these genes tends to reduce the function of proteins which affects the regulation of the cell that particularly disrupts the development of the face, head and the development of the skull.
Symptoms
Typically the affected children have a cleft which can extend up to the forehead from the upper lip, wide-spaced eyes, V-shaped hairline and a flat nose that can be divided by the cleft. They may also exhibit a missing nasal tip and the hearing loss. Problems of the central nervous system includes corpus callosum when two halves of the brain do not connect, protrusion of the brain tissue, developmental delay and varying degree of mental retardation although most of the affected cases appear to have normal intelligence. In addition, they may also have congenital heart abnormalities and skeletal problems such as the underdeveloped shin bone.
Diagnosis
The diagnosis of this disorder is possible by prenatal ultrasound that identifies the abnormities. Alternatively, the diagnosis is possible at the birth of the infant with the features that are characteristic of this condition. The head and the face may require a CT scan along with the MRI of the brain that may be conducted for further evaluation and accordingly surgical intervention may be planned. In addition, the genetic testing for this condition is only available on a research basis.
Treatment
The treatment for these affected individuals is based on the severity of the condition that varies with each case. Accordingly, a surgery may be required to correct the eye socket position, repair the cleft and other craniofacial abnormalities. Depending on the cases, additional surgery may be required when the affected child becomes older to correct the eyelid position and the nose. In addition, they may also require educational and special social services. Genetic counseling may also be beneficial for some of the affected individuals.
References
https://rarediseases.org/rare-diseases/frontonasal-dysplasia/
https://ghr.nlm.nih.gov/condition/frontonasal-dysplasia#genes
http://www.ccakids.org/assets/syndromebk_frontonasal_dysplasia.pdf
