Impact of enzyme replacement therapy on linear growth in Korean patients with mucopolysaccharidosis type II (Hunter syndrome).

Abstract

Hunter syndrome (or mucopolysaccharidosis type II [MPS II]) arises because of a

deficiency in the lysosomal enzyme iduronate-2-sulfatase. Short stature is a

prominent and consistent feature in MPS II. Enzyme replacement therapy (ERT) with

idursulfase (Elaprase(R)) or idursulfase beta (Hunterase(R)) have been developed

for these patients. The effect of ERT on the growth of Korean patients with

Hunter syndrome was evaluated at a single center. This study comprised 32

patients, who had received ERT for at least 2 yr; they were divided into three

groups according to their ages at the start of ERT: group 1 (<6 yr, n=14), group

2 (6-10 yr, n=11), and group 3 (10-20 yr, n=7). The patients showed marked growth

retardation as they got older. ERT may have less effect on the growth of patients

with the severe form of Hunter syndrome. The height z-scores in groups 2 and 3

revealed a significant change (the estimated slopes before and after the

treatment were -0.047 and -0.007, respectively: difference in the slope, 0.04;

P<0.001). Growth in response to ERT could be an important treatment outcome or an

endpoint for future studies.