HTT and juvenile Huntington disease: To date, in the result of many studies of the molecular, genetic, and cellular basis of Huntington’s disease, answers to the fundamental questions that have been enigmatic for more than 100 years have received: (1) the gene encoding for the HTT protein has cloned; (2) the mutation, which leads to the expression in the cells a defective protein responsible for this disease has explored; (3) it has found, that HTT participates in many intracellular processes mediated by MTs and other cytoskeletal cell structures.