Take a look at the CHIN! --early diagnosis of isolated agnathia using two- and three-dimensional sonography.

Agnathia is a very rare malformation characterized by the absence of the mandible, which occurs either as an isolated malformation or in association with other deformities. We report the first case of an isolated agnathia diagnosed at 12 weeks due to the absence of the chin; the case was diagnosed using two- and three-dimensional ultrasonography and was confirmed by pathological analysis after the pregnancy was medically terminated at 17 weeks. Usually, isolated agnathia is a lethal malformation and its prenatal diagnosis is often delayed beyond the second trimester of pregnancy. We therefore suggest a systematic 'look at the CHIN', i.e. Chin, Headbone outlines (skull and nasal bones), Inner head, Nuchal translucency, using the sagittal view of the cephalic pole at 12 weeks.