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.
The first clue and most obvious symptom is that the eye doesnât look right. Specifically, its normally black pupil may look white. In a photo, instead of red eye, a child with retinoblastoma will have one pupil that glows white when light shines on it. These symptoms can also be caused by less serious problems.