The abnormal nucleus as a cause of congenital facial palsy.

BACKGROUND Congenital facial palsy (CFP) is clinically defined as facial palsy present at birth. It is associated with considerable disfigurement and causes functional and emotional problems for the affected child. The aetiology of the majority of cases however, remains elusive. AIMS To investigate the role of a neuroanatomical abnormality as a cause of unilateral CFP. METHODS Magnetic resonance imaging (MRI) scans were performed on 21 patients with unilateral CFP. Fifteen patients had unilateral CFP only; six suffered from syndromes which can include unilateral CFP. RESULTS Of the 15 patients with unilateral CFP only, four (27%) had an abnormal nucleus or an abnormal weighting of this area on the MRI scan, compared to one (17%) of the remaining six patients. CONCLUSION Developmental abnormalities of the facial nucleus itself constitute an important, and previously ignored, cause of monosymptomatic unilateral CFP.