??? ??? ?? ? ? ?? ?? ??? ????? ??? ?? ??? ???? ??? ???? ?????.???? ??? ? ?? ??: ??? ??? ???? ???? ??? ? ????.A chromosomal abnormality consisting with the absence of one of many copies of chromosome seven in somatic cells. [from NCI]By adolescence, all people with MLIV have intense visual impairment. A neurodegenerative part of MLIV has become add