???? ??? ?? ?? ? ????? ? ?? ??? ?? ???? ??? ??? ? ??? ? ??? ? ?? ? ??? ??? ??????.Trichothiodystrophy, usually named TTD, is a exceptional inherited issue that affects quite a few elements of the human body. The hallmark of the problem is hair that is sparse and simply damaged. [from MedlinePlus Genetics]?? ??? ????? ??? ??? ???? ???? ??? ??? ?? ??