Facial Paresis, Hereditary Congenital, 2

For a phenotypic description and a discussion of genetic heterogeneity of hereditary congenital facial paresis (HCFP), see 601471.

Clinical Features

Fortanier and Speijer (1935) reported a family with hereditary facial weakness. Nicolai et al. (1986) reported further on this family, which had 9 affected members spanning 4 generations. Affected members had unilateral or bilateral facial weakness. Weakness of the muscles of the 3 branches of the facial nerve varied among individuals. Besides facial weakness, 3 patients also had variable hearing loss. In 1 patient with hearing loss, there was a deformity of the petrous portion of the temporal bone.

Mapping

By genomewide analysis of the family reported by Fortanier and Speijer (1935), Verzijl et al. (1999) found linkage to a 3.7-cM locus at chromosome 10q21.3-q22.1 between markers D10S581 and D10S502. Penetrance in the family was estimated to be 60%, given 5 obligate carriers and 9 clinically unaffected individuals in which haplotypes of the critical region indicated the 'affected' genotype. The reduced penetrance in the family suggested that some 'sporadic' cases of HCFP may in fact be autosomal dominant, where other affected members are not recognized in the family or as new dominant mutations.