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