We measured protein S (PS) activity in a large group of Japanese subjects t
o study the frequency of PS deficiency. The study group comprised 213 men,
ages 18-58 years, and 179 women, ages 18-60 years. PS activity in the total
392 subjects was 58-135% (mean +/- 2 SD), 65-135% in the men and 54-120% i
n the women. The men showed significantly higher levels of PS activity than
the women (p < 0.001). We identified 8 subjects (4 men and 4 women) in who
m PS activity was lower than the mean-2SD for men and women, respectively.
Moreover, we examined the classifications of PS deficiency. The frequency o
f PS deficiency in this study was 2.04% (Type I: 0.51%, Type II: 1.02%, Typ
e III: 0.51%). Based on our findings, it would appear that the frequency of
Type II PS deficiency in the Japanese population is approximately 1%. The
screening of PS decrease should be judged by activity. (C) 2000 Elsevier Sc
ience Ltd. All rights reserved.