????? ??? ??, ?? ??? ??? ??? ? ?? ?? ??????. ???? ???? ??? ? ?? ?? ??? ?????.???? ??? ? ?? ??: ??? ??? ???? ???? ??? ? ????.A chromosomal abnormality consisting of your absence of among the list of copies of chromosome 7 in somatic cells. [from NCI]By adolescence, all people with MLIV have critical visual impairment. A neurodegenerative part of ML