Moebius syndrome is a disorder affecting the cranial nerves that control movement of the face. People affected by the disorder lack any facial expression, including smiling, and may have an array of other symptoms such as deafness and deformities of the limbs. Because there are multiple forms of the disease, depending on which cranial nerves are affected, and many ways in which symptoms can manifest, the differential diagnosis includes a range of other neurologic, degenerative, and metabolic disorders.
Basilar Artery Thrombosis
Thrombosis or occlusion of the basilar artery can lead to neurologic impairment that can include problems with vision, impaired movement of the eyes and loss of movement. However, basilar artery thrombosis is an acute event representing a life-threatening emergency. Its other symptoms include loss of consciousness, behavioral anomalies, and sleepy behavior. It can lead to sudden death. Angiography is used to diagnose basilar artery thrombosis.
Tumors of the brainstem can cause some symptoms resembling Moebius syndrome. These tumors comprise 10-20% of all childhood brain tumors. Symptoms include visual disturbances, difficulty walking, difficulty swallowing, headache, nausea, vomiting, and behavioral changes. Cranial nerve deficits are typically observed, particularly affecting cranial nerves VI and VII, which can cause loss of sensation in the face. Diagnosis of brainstem glioma will include imaging studies of the brain, examination of the CSF, and arteriography.
Congenital Muscular Dystrophy and Congenital Myopathies
The congenital muscular dystrophies are a group of autosomal recessive diseases that cause weakness starting at birth. Congenital myopathy is a disease with onset early in life causing hypotonia, hyporeflexia, and overall weakness. These illnesses are typically diagnosed with the help of laboratory and imaging studies.
Myasthenia gravis is a rare autoimmune disorder affecting the peripheral nerves of the body. Myasthenia gravis can cause the facial muscles to be slack along with weakness or limpness in other parts of the body.
Focal Muscular Atrophy
Focal Muscular Atrophy could cause symptoms resembling Moebius syndrome. It can be challenging to diagnose.
Spinal Muscular Atrophy
Spinal muscular atrophy causes progressive weakness of those parts of the body that are controlled by the lower motor neurons. There are a number of types of spinal muscular atrophy. The most common are acute infantile (SMA type I), chronic infantile (SMA type II), chronic juvenile (SMA type III) and adult onset.
Exposure to a toxic chemical or drug can lead to a range of symptoms, including blurred vision, tachycardia, loss of sensation, and motor dysfunction. Some common toxins that can lead to neuropathy are thallium, dimethylaminoproprionitrile, alcohol, carbon disulfide, ethylene oxide, mercury, and lead. Diagnosis can be made through a medical history aimed at eliciting all potential exposures, followed by sensory testing, intraepidermal nerve fiber density testing, sympathetic skin reflex, electromyography, and nerve conduction tests.
Further conditions to be considered in the differential diagnosis of Moebius syndrome include:
- cerebral palsy
- metabolic myopathies
- peripheral nerve injuries
- acquired facial palsy from delivery
- cardiofacial syndrome
- Duane syndrome
- oromandibular-limb hypogenesis disorders
- Hanhart syndrome
- glossopalatine ankylosis
- Charlie M syndrome
- Athabascan brainstem dysgenesis syndrome
- Poland anomaly
- Klippel-Feil anomaly