Koolen-de Vries syndrome (KDVS) is characterized by moderately to severely impaired intellectual development, hypotonia, friendly demeanor, and highly distinctive facial features, including tall, broad forehead, long face, upslanting palpebral fissures, epicanthal folds, tubular nose with bulbous nasal tip, and large ears. More variable features include cardiac or genitourinary anomalies and seizures (summary by Koolen et al., 2012). [from
OMIM]