However, people with KdVS typically live at least into adulthood. For children with epilepsy, seizures may be hard to control.

Gabriele-de Vries syndrome is characterized by mild-to-profound developmental delay / intellectual disability (DD/ID) in all affected individuals and a wide spectrum of functional and morphologic abnormalities. Intrauterine growth restriction or low birth weight and feeding difficulties are common.

Males with Koolen de Vries syndrome often have undescended testes (cryptorchidism). Other symptoms may include defects in the walls between the chambers of the heart (septal defects) or other heart defects, kidney problems, and skeletal anomalies such as foot deformities.

Coffin-Siris syndrome is a condition that affects several body systems. Although there are many variable signs and symptoms, hallmarks of this condition include developmental disability, abnormalities of the fifth (pinky) fingers or toes, and characteristic facial features.