Table 1. Clinical, biochemical and molecular details of the Indian patients with Tay Sachs disease.

S no	Age at diagnosis	Native State	Consan- guinity	Hex-A activity (MUGS) (nmol/hr/mg)  =  (x)	Total Hex activity (MUG)  =  (y)	Hex A %  =  (x/y) X 100	Genotypes (nucleotide level)	Genotypes (protein level)
1	11 months	Gujarat	No	4.5	ND	-	c.1385A>T/c.1385A>T	p.E462V/p.E462V
2	1.5 Yrs	Gujarat	No	4.8	1827.6	0.2	c.1385A>T/c.1385A>T	p.E462V/p.E462V
3	1 Yrs	Gujarat	No	5.9	2208.9	0.26	c.1385A>T/c.1385A>T	p.E462V/p.E462V
4	1.5 Yrs	Gujarat	No	5.1	2009	0.25	c.1385A>T/c.1385A>T	p.E462V/p.E462V
5	1.5 Yrs	Gujarat	No	5.8	2288	0.25	c.1385A>T/c.1385A>T	p.E462V/p.E462V
6	11 months	Gujarat	No	0.0 Father -60% (HLC) Mother –53% (HLC)	2131.0 731.7 528.3	0.0 - -	c.1385A>T/c.1385A>T	p.E462V/p.E462V
7	2.5 Yrs	Uttar Pradesh	No	4.08	1453.0	0.28	c.964 G>A/c.964 G>A	p.D322N/p.D322N
8*	15 months	Uttar Pradesh	No	0.0	716.2	0.0	Father and mother - [c.964 G>T/−]	p.D322Y/−
9	10 months	Maharashtra	No	23.8	1840.2	1.29	c. 340 G>A/c.340 G>A	p.E114K/p.E114K
10	1 Yrs	Maharashtra	No	7.2	2100	0.3	c.672+30T>G/c.1432 G>A	Undetermined/p.G478R
11	18 months	Tamil Nadu	Yes	17.2	2054.5	0.83	c.1178 G>C/c.1178 G>C	p.R393P/p.R393P
12*	1 Yrs	Andhra Pradesh	Yes	Father- 59.3% (HLC) Mother - 59.1% (HLC)	ND	-	Father -[c.805+1 G>C/−] Mother -[c.805+1 G>C/−]	-
13	1.5 Yrs	Iraq	Yes	18.4	1776.9	1.03	c.508C>T/c.508C>T	p.R170W/p.R170W
14	1 Yrs	Karnataka	Yes	1.5	1660	0.09	Not found	-
15	16 months	Gujarat	No	2.1	ND	_-	Father and mother - [c.1277_1278insTATC/−]	-

^*DNA of index case is not available, HLC-heat labile activity in carrier parents, ND – not done.

Normal total hexosaminidase values using MUG substrate in our controls –703 to 1785 nmol/hr/mg protein, normal hexosaminidase A levels – (62 to 77%); normal MUGS activity 80 to 390 nmol/hr/mg.