Unexplained right atrial enlargement may be a sign of Holt-Oram syndrome in the fetus.

Two cases of ultrasound diagnosis of Holt-Oram syndrome are described. Both were characterized by significant right atrial enlargement that was not due to concurrent tricuspid regurgitation or other cardiac anomalies. In both cases the associated skeletal anomaly was subtle and barely visible using ultrasound. Interestingly, despite the fact that Holt-Oram syndrome is also called atriodigital dysplasia, unexplained right atrial enlargement has not been described in this context in the fetus before. When such a finding is detected, we believe a thorough search for upper limb abnormalities should be carried out and genetic testing for Holt-Oram syndrome should be discussed with the parents.