Alveolar capillary dysplasia with antenatal anomalies mimicking trisomy 21.

Alveolar capillary dysplasia (ACD) has been described in conjunction with a number of congenital abnormalities. The case reported here was noted in utero to have duodenal atresia and a partial atrioventricular canal defect and a provisional diagnosis of trisomy 21 was considered. A fetal blood sample showed a normal karyotype. The diagnosis of ACD was made at post-mortem following a neonatal death on the tenth day. This case further highlights the range of congenital abnormalities that may be present in cases of ACD that may mimic other conditions, including trisomy 21, on antenatal scan. However, the absence of congenital anomalies, even in the same family, would not exclude the diagnosis of ACD.