Tay-Sachs disease displays a variety of forms on the clinical and biochemical 
level. On the molecular level it has been shown, that poly (A)+ RNA preparations 
from fibroblasts of patients with classical Tay-Sachs disease lack detectable 
alpha-chain message when analyzed by Northern blotting with complementary DNA 
encoding the alpha-chain of human beta-hexosaminidase A. In this report the p 
beta H alpha-5 clone was used to investigate whether patients with two different 
variants of Tay-Sachs disease also lack the alpha-chain message. On the basis of 
RNA hybridization analyses, we could show that our patients which synthesize an 
altered alpha-chain, as judged by testing enzyme activity and substrate 
specificity, have the 2.1 kb mRNA which is also seen in healthy control 
patients.