“Moebius syndrome is a rare neurological disorder characterized by weakness or paralysis (palsy) of multiple cranial nerves, most often the 6th (abducens) and 7th (facial) nerves. Other cranial nerves are sometimes affected. The disorder is present at birth (congenital). If the 7th nerve is involved, the individual with Moebius syndrome is unable to smile, frown, pucker the lips, raise the eyebrows, or close the eyelids. If the 6th nerve is affected, the eye cannot turn outward past the midline. Other abnormalities include underdevelopment of the pectoral muscles and defects of the limbs. Moebius syndrome is not progressive. The exact cause is unknown. It appears to occur randomly (sporadically) in most cases; however, some cases occur in families suggesting that there may be a genetic component.”

NORD (https://rarediseases.org/rare-diseases/moebius-syndrome/)