Prenatal Diagnosis of Achondroplasia with Ultrasound, Three-Dimensional Computed Tomography and Molecular Methods

A 29-year-old female was transferred to our clinic because of short femurs (<2 percentile) on ultrasound scan. She had nonspecific medical and obstetrical history. The ultrasound scan at 32 weeks of gestational age revealed rhizomelic shortening of the extremities, frontal bossing and the over rounded metaphyseal - epiphyseal interface at the femur ends while connecting to diaphysis, also called “collar hoop” sign. A 3D helical computed tomography (3D-HCT) scan reported rhizomelic limbs, narrowing of the interpediculate distance of the lumbosacral spine, rounded iliac wings and bilateral “collar hoop” sign of the proximal femurs. All these findings led to diagnosis of achondroplasia, which was confirmed by DNA testing. A well, active male baby was born. Postnatal x-ray also confirmed antenatal findings of ultrasound and 3D-HCT.