Prenatal diagnosis of asphyxiating thoracic dysplasia (Jeune syndrome).

Asphyxiating thoracic dysplasia (ATD), or Jeune syndrome, is an uncommon autosomal recessive skeletal disorder characterized by a small thorax, varying degrees of rhizomelic brachymelia, polydactyly, pelvic abnormalities, and renal anomalies. We describe prenatal sonographic examinations in the third trimester of a fetus with abnormal small thorax, short limbs, polyhydramnios, and absence of fetal respiratory movements. At 36 weeks gestation, the fetal biparietal diameter was 93 mm, compatible with 37 weeks; the long-bone lengths measured < 5th percentile; the thoracic circumference (TC) measured 230 mm (< 5th percentile); the abdominal circumference (AC) measured 286 mm (25th percentile), and the TC/AC ratio was 0.80 (lower limit of normal). Our case shows that, although a discrepancy between gestational age and TC is prominent, TC/AC ratio may reach lower limit of normal in cases of fetal ATD, when fetal growth is compromised.