??? ??? ?? ? ? ?? ?? ??? ????? ??? ?? ??? ???? ??? ???? ?????.????? ??? ????? ???? ????.????? ???? ??? ??? ??? ???? ?????.A chromosomal abnormality consisting of your absence of one of many copies of chromosome seven in somatic cells. [from NCI]By adolescence, all people today with MLIV have severe visual impairment. A neurodegenerative component