| A chromosomal condition occurring when a piece of the long (q) arm of chromosome 18 is missing near the center of the chromosome. The disease has a wide range of characteristics including developmental delay, intellectual disability, delayed expressive language skills, recurrent seizures and hypotonia. Macrocephaly may also be associated along with characteristic facial features including prominent forehead, ptosis, downslanting palpebral fissures, puffy periorbital tissue, and full cheeks. Most cases of proximal 18q deletion syndrome are the result of a new (de novo) deletion and are not inherited from a parent. |
