Third-trimester 3D Ultrasound Evaluation of Thanatophoric Dysplasia Type I

摘要

A 34-year-old primigravida woman was referred to the hospital at 31 gestational weeks because of limb deformities in the fetus. The woman and her husband were healthy, and there was no family history of skeletal abnormalities. Two-dimensional (2D) ultrasound examination revealed polyhydramnios, frontal bossing, a depressed nasal bridge, a narrow chest, a protuberant abdomen, macrocephaly, shortening of the long bones, and bowing in the femurs (Figure 1). The amniotic fluid index was 300 mm. The femur length measured 2.52 cm (normal, 5.39-6.39 cm), tibia length 1.72 cm (normal, 4.82-5.98 cm), fibula length 1.89 cm (normal, 4.68-6.18 cm), humerus length 2.08 cm (normal, 4.85-6.01 cm), ulna length 2.11cm (normal, 4.58-5.94cm) and radius length 1.98cm (normal, 3.97-5.33 cm). The long-bone measurements were below the 5th percentile of the normal biometry. The thoracic circumference (TC) was 18.79 cm (normal, 20-25.5 cm).