Messenger RNA encoding GPVI is present in the patient's platelets. Samples of mRNA isolated from the patient's platelets and those of a control donor were reverse transcribed. Two fragments of 547 bp and 540 bp, respectively, were amplified by PCR as described in “Materials and methods” and analyzed by electrophoresis in agarose gels. Lanes 1 to 4 and 5 to 8 correspond to the 8-554 and 472-1011 fragments, respectively, obtained with 2 μL (lanes 1, 3, 5, and 7) and 4 μL (lanes 2, 4, 6, and 8) samples. Control cDNA (lanes 1, 2, 5, and 6) and patient cDNA (lanes 3, 4, 7, and 8) are shown. Note the normal intensity and migration of the fragments corresponding to the patient's cDNA. Also shown are molecular size markers.