Department of Pediatric Pathology, Karolinska Sjukhuset, Stockholm, Sweden
Department of Pathology, Karolinska Sjukhuset, Stockholm, Sweden
Department of Diagnostic Radiology, Karolinska Sjukhuset, Stockholm, Sweden
*Supported by grants from `Expressens Prenatalforskningsfond', `Stiftelsen Gustav och Tyra Svenssons Minne' and the `Swedish National Association against Heart and Chest Disease'.