duete; see due, ty 2 ]. syn: duty, obligation refer to something a person feels bound to do. A duty often applies to what a person performs in fulfillment of the permanent dictates of conscience, piety, right, or law: one's duty to tell the truth; a parent's duty to raise children properly.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way.
In about 80%â90% of hereditary retinoblastoma cases, the child is the first person in the family to have the condition. In these cases, the RB1 mutation either arose in an egg or sperm cell that formed the child or in one of the childâs cells during pregnancy.