Trisomy 18 syndrome

Definition

A rare chromosomal abnormality characterized by the presence of an extra chromosome 18 material and manifesting with severe intellectual disability growth delay, and extremely variable multiple congenital anomalies, including minor malformations (cranio-facial dysmorphia, short sternum, overlapping fingers) and major malformations, especially cardiac and cerebral. Neurological involvement may lead to seizures and hypotonia.