[Sandhoff's disease (GM2 gangliosidosis, type II). Presentation of a case with a clinical and biochemical study. Carrier detection].

A case affected by Sandhoff's disease is reported, with clinical and biochemical studies. In the propositus, total absence of hexosaminidases is reported. In parents hexosaminidase A is present, but hexosaminidase B is decreased. In the carriers there is a total low activity of hexosaminidase and a lower proportion 20% of hexosaminidase is confirmed.