Table 2.
Biochemical and mutation data
| Patient | Enzyme assay in plasma | HEXB mutation | ||||
|---|---|---|---|---|---|---|
| Total HEX (% of normal range)a | HEX-B activity (% of normal range)b | % HEX-A/ total HEXc | Zygosity | Base change | Amino acid change | |
| 1 | 21.9 (3.0%) | 3.0 (1.1%) | 89.0 | homo | c.1652G>A | p.Cys551Tyr |
| 2 | 70.2 (9.6%) | 7.7 (2.7%) | 89.0 | homo | c.1652G>A | p.Cys551Tyr |
| 3 | 48.9 (6.7%) | 7.6 (2.6%) | 84.5 | homo | c.1652G>A | p.Cys551Tyr |
| 4 | 33.1d (4.1%) | NA | 95.1d |
het het |
c.1652G>A c.761 T>C |
p.Cys551Tyr p.Leu254Ser |
| 5 | 46.1 (6.3%) | 2.6 (0.9%) | 94.5 | homo | c.1652G>A | p.Cys551Tyr |
het heterozygous, homo homozygous
a Total HEX reference range: 729 ± 225.6 nmol/hr./ml; % of normal range as compared to the according mean reference range
b HEX-B activity reference range: 288.9 ± 59.1 nmol/hr./ml; % of normal range as compared to the according mean reference range
c % HEX-A/total HEX reference range: 59.3 ± 6.3%
d reference ranges for total enzyme activity and % HEX-A/total HEX activity were 801 ± 190 nmol/mg prot/hr. and 55–72%, respectively (National Taiwan University Hospital Laboratory)