Moebius syndrome is a rare disease that is characterized clinically by the lack of a smile. It does not happen for lack of happiness, but for the impossibility of making the gesture of laughter .
Moebius syndrome is a rare and rare pathology, although it seems that its incidence is increasing. The last congresses of neurology and ophthalmology in the world account for the increase in registered cases.
We can say that the main characteristic of Moebius syndrome is the lack of ability to smile; Although those affected go through happy situations and wish to sketch a smile, they cannot.
But not only that. Patients with this rare disorder cannot perform many of the classic and typical facial gestures. They even affect their ability to move their eyes from side to side, for example.
This happens because they have not partially or completely developed two pairs of cranial nerves: pair number six and pair number seven. These nerves handle the mimicry muscles and part of the muscles that perform some eye movements.
As we will see later, each pair of cranial nerves has specific functions. The number six nerve regulates the laterality of the eye, and the number seven is called the “facial nerve” because it handles facial expressions.
We know that Moebius syndrome usually appears in isolation. In other words, it is not common for a family to have more than one confirmed case. It is estimated that one in one hundred and twenty thousand people is born with a problem.
What are the cranial nerves?
Let’s first look at the pairs of cranial nerves and their functions, and then understand why Moebius syndrome has the symptoms it has. The cranial nerves are:
- Olfactory: it carries the information to perceive odors.
- Optical: it is the nerve of vision.
- Oculomotor: it is the third cranial nerve and innervates part of the eye movement muscles.
- Pathetic: also innervates muscles of eye movement.
- Trigeminal: involved in chewing.
- External ocular motor: one of those affected in Moebius syndrome.
- Facial: the other nerve affected in the pathology.
- Auditory: it carries the information we hear to the brain.
- Glossopharyngeal: transmits part of the taste that captures the tongue.
- Vague: it extends outside the skull to reach the chest and abdomen.
- Accessory: it also extends outside the skull to the neck and back muscles.
- Hypoglossal: innervates muscles of the tongue and neck.
Etiology of Moebius syndrome
It should be clarified that although it is known as a syndrome, it is not. Moebius is what in genetics is known as a sequence. In the sequences there are many malformations at the same time, originating in a single anomaly.
In the case of Moebius, the anomaly is the lack of development or the total absence of nerve nuclei in cranial nerves number six and seven. Both the imaging studies performed on patients and the necropsies performed coincide in the diagnosis.
The etiology is not always genetic. There have been cases in which the problem of cranial nerves is caused by medication. Misoprostol is the drug that has been most associated with the problem.
Said medicine, in general, is used as an abortifacient, and if it fails for that use, the pregnancy that continues may develop Moebius syndrome.
Symptoms of Moebius syndrome
Newborns with Moebius syndrome not only lack facial expression but also often have difficulty breathing. They drool excessively and their muscle tone is weak, which can affect walking.
If we add to this the possibility that those affected suffer from deformities in the feet, the displacement is really at risk of delay. Other symptoms that have been registered as associates are:
- Hypersensitivity to the sun and strong lights
- Lack of eyelids
- Ogival Palate
- Hearing problems due to fluid accumulation in the inner and middle ear 
There is no cure for Moebius syndrome. Once it has been installed, it is not completely reversible. Facial rehabilitation sessions have not demonstrated effectiveness.
There is an experimental surgical treatment that has started in Canada. It consists of an intervention where a muscle graft is performed in the facial area to allow the expression of the smile.
It is estimated that the greatest success of the surgery is to perform it when the patient is around five years old. Although the practice is promising, the truth is that it is not available worldwide and the access costs are not universal either.
One of the struggles that relatives of patients with Moebius syndrome carry out is to avoid discrimination. For this reason, they try to raise awareness in the population, emphasizing that those affected have feelings, although they cannot express them.
The Bottom Line
Treatments are still being experienced in the medical world. Surgical projections are encouraging. Meanwhile, it is essential to respect these patients and understand that their inclusion in social life depends on the greater knowledge they can have of their condition. Published By Healthzigzag.com