Micrognathia-prenatal ultrasonographic diagnosis.

The first case of prenatal real-time ultrasonographic diagnosis of micrognathia is presented. Diagnosis was made at 17 weeks' gestation in the fetus of a patient with previous infant affected with the syndrome of thrombocytopenia with absent radii (TAR). Recognition of micrognathia as a part of TAR syndrome and the easy visualization of fetal facial bones in the second trimester made diagnosis possible.