[Prenatal diagnosis of thanatophoric dwarfism].

Thanatophoric dwarfism is a rare malformation, occurring in less than 1:10,000 pregnancies. It can be discovered by standard ultrasound examination, but other skeletal dysplasias such as achondroplasia, achondrogenesis and polydactyly syndromes must be taken into consideration. Sonographic findings are polyhydramnia, narrow chest, symmetric tetramicromelia and macrocephaly. Macrocephaly might cause a problem for vaginal delivery. The narrow chest with secondary lung hypoplasia determines the infaust prognosis.