Symptoms:  What are the signs of Moebius Syndrome?

For Moebius syndrome to be diagnosed, a patient must have complete or partial facial nerve (CN VII) paralysis. Most Moebius patients show incomplete bilateral palsy (i.e., on both sides of the face, but with at least a little functionality). Palsies of other cranial nerves, either bilaterally or unilaterally (i.e., either on one side only or on both sides), are quite common, especially palsies of the abducens nerve (CN VI) and palsies of the hypoglossal nerve (CN XII).

These palsies of the cranial nerves result in a variety of symptoms. The facial muscles of the upper face are paralyzed or very weak, and a child with Moebius syndrome will not make normal facial expressions such as smiling or wrinkling of the face when crying. The facial paralysis also manifests itself as an inability to control drooling and a poor sucking ability. The inability to suck is of great concern if not diagnosed because the child may not be able to acquire proper nutrients when nursing. Dysfunction of the hypoglossal nerve, which innervates the muscles of the tongue, exacerbates the problems with nursing. Moebius patients with palsy of the abducens nerve cannot abduct their eyes past the midline. Abducens palsy also often results in strabismus (being cross-eyed). Interestingly, most Moebius syndrome patients have normal reading speed and reading comprehension.

Limb deformations are also a common symptom of Moebius syndrome. Club foot occurs frequently, along with webbed fingers or toes (i.e., syndactyly) or various other minor deformations of the hands or feet.  

Some studies have also linked respiratory problems with Moebius syndrome. Sleep apnea seems to occur frequently with Moebius, and some Moebius patients even have a higher than normal resting respiratory rate. 

For an explanation of why these symptoms are manifested in Moebius syndrome, see the next page: Pathology