Comparison of mRNA levels of R333Q-hFIX and wild-type mice. mRNA level was measured by qPCR. The results are given as percentage of wild-type mouse mRNA. Homozygotes (H/H) represent 39%, hemizygotes (H/Y) 48%, and heterozygotes (H/+) 87% of wild-type (WT) mRNA levels. Homozygous refers to the R333Q mouse and heterozygous refers to a mouse with copies of human R333Q and wild-type mouse factor IX. Data represent the mean ± SD.