Background Idiopathic facial nerve (Bell’s) palsy is the most common cause of peripheral facial nerve palsy with a familial link reported in up to 28% of cases. An autosomal dominant trait with variable penetrance has been proposed. We here present Bell’s palsy affecting four family members and a literature review.
Case Report A 46-year-old female presented with an acute onset of left sided facial palsy 2 years earlier. MRI showed neuritis affecting a short intracanalicular segment of the left facial nerve. Investigations revealed no underlying cause. The patient had partial recovery of the facial palsy. She developed synkinesis and hyperkinesis affecting the periorbital area and the midface with persistent weakness of the marginal branch and ongoing facial pain. She underwent Botox injections to the upper face which improved facial symmetry and a digastric transfer to the lower lip. The patient’s sister, mother and her paternal grandmother also suffered Bell’s palsy at the ages of 19, 68 and mid-60s, respectively, all resolved within three months. Her mother subsequently developed a right oculomotor, right abducens and further left oculomotor palsy, all of which resolved spontaneously. Two other siblings had Ellis-van Creveld syndrome.
Discussion Anatomic, immunologic, vascular and autonomic factors have been proposed as possible mechanisms underscoring familial Bell’s palsy. The role of human leukocyte antigen expression remains unclear, but highlights a possible autoimmune component. A structural predisposition from heritable facial canal morphology has also been proposed. Many reported cases are associated with multiple cranial nerve involvement and ophthalmoplegia amongst family members. Prognosis in familial cases varies with some reporting a more favourable outcome whilst others highlight an increased likelihood of recurrence of facial palsy with associated risk of delayed recovery.
Conclusion The familial Bell’s palsy affecting both maternal and paternal family members reported here suggests a hereditary link.