Early Prenatal Diagnosis of Thanatophoric Dysplasia : A Report of Three Cases

Abstract

Three pregnant women prenatally diagnosed with thanatophoric dysplasia at 18, 19 and 21 weeks of gestation were reported. All of them were without significant previous medical and familial diseases. Sonographic evaluation was perfomed due to premature contraction or large for date measurements. In each of them, the sonographic findings demonstrated polyhydramnios, enlarged cranium, narrow thorax and severe micromelia of all extremities but normal ossification. Based on the sonographic features, the diagnoses of lethal short limbed skeletal dysplasia were made and were most likely related with thanatophoric dysplasia however the pregnancies were terminated. Postnatal ra diographs of all three cases showed the intact calvarium, normal ossification, large head size, narrow thorax with normal ossified ribs, flattened vertebral bodies (platyspondylisis, H-shape or U-shape), severe rhizomelic dwarfism but all the extremities wereextremely foreshortened, with femurs bowing. These findings were compatible with the diagnosis of thanatophoric dysplasia. (Thai J Obstet Gynaecol 1994;6:37-42).