Tay-Sachs disease (TSD) is a recessively inherited disorder caused by the 
deficient activity of hexosaminidase A due to mutations in the HEXA gene. Up to 
date there is no information regarding the molecular genetics of TSD in 
Argentinean patients. In the present study we have studied 17 Argentinean 
families affected by TSD, including 20 patients with the acute infantile form 
and 3 with the sub-acute form. Overall, we identified 14 different mutations 
accounting for 100% of the studied alleles. Eight mutations were novel: 5 were 
single base changes leading to drastic residue changes or truncated proteins, 2 
were small deletions and one was an intronic mutation that may cause a splicing 
defect. Although the spectrum of mutations was highly heterogeneous, a high 
frequency of the c.459+5G>A mutation, previously described in different 
populations was found among the studied cohort. Haplotype analysis suggested 
that in these families the c.459+5G>A mutation might have arisen by a single 
mutational event.