??? ??? ?? ? ? ?? ?? ??? ????? ??? ?? ??? ???? ??? ???? ?????.????? ??? ????? ???? ????.????? ???? ??? ??? ??? ???? ?????.A chromosomal abnormality consisting on the absence of one of several copies of chromosome 7 in somatic cells. [from NCI]Retinoblastoma is usually a malignant tumor on the acquiring retina that occurs in little ones, typically