From my investigation of one rare family subject to athetose double, I have come to the following conclusions. 1. Athetose double is manifest in all the 3 sublings of a family I have observed. Formes frustes were evident in their father and grandfather on paternal side. The father and mother are cousins. Their half-sister by their step-mother is normal. The brothers' mother is degenerant. Amoung their parents' parents and great uncles and great aunts and great grandfather, there were five degenerants and drunkards. 2. Though athetose double appears to be of ressesive character, it is really not so simple, and this makes me venture a theory of "Dominance Change".