Quantitative analysis of GPVI mRNA. Total RNA was prepared from washed platelets, reverse transcribed, and amplified with GPVI-specific PCR primers using 0.1 and 10 ng cDNA equivalents (see “Materials and methods”). GPVI transcript levels were normalized to those of GPIIb to determine copy number/ng template. Note that patient GPVI mRNA levels (▪) are indistinguishable from those of a healthy control (▦).