DOWN'S SYNDROME (TRISOMY 21) Ércio Filho, MD., MA in Pediatrics by the State University Rio Grande do Sul (UFRGS). What's it? Down's syndrome is the most common form of mental retardation caused by a microscopically demonstrable chromosomal abnormality. It's characterized by well defined phenotypic aspects and natural history. It's caused by the occurrence of a… Continuar lendo DOWN’S SYNDROME (TRISOMY 21)