Intellectual disability-hypoplastic corpus callosum-preauricular tag syndrome is characterised by a hypoplastic corpus callosum, microcephaly, severe intellectual deficit, preauricular skin tags, camptodactyly, growth retardation, and recurrent bronchopneumonia. It has been described in four patients in two families. Transmission is autosomal recessive.

Distance between the commissures of the mouth more than 2 SD below the mean. Alternatively, an apparently decreased width of the oral aperture (subjective).