Prenatal Diagnosis of Achondrogenesis Type 2 in the Early Second Trimester by using Three-Dimensional Computed Tomography

Achondrogenesis type 2 (ACG2) is a lethal skeletal disorder that is characterized by extremely short limbs with cupped and splayed metaphyses and poor vertebral body ossification. A 23-year-old Japanese woman (gravida 1, para 0) was referred to our hospital at 19 weeks and 0 days gestation with the fetus having severe shortening of the long bones. According to ultrasonographic examination, thanatophoric dysplasia type 1 or ACG2 was suspected. Therefore, we performed three-dimensional computed tomography (3D-CT) which showed the lack of ossification of the fetal vertebral bodies clearly. We diagnosed ACG2, and the parents decided on termination of the pregnancy. Here we report a case of ACG2 that was clearly identified with 3D-CT in the early second trimester.