Compound heterozygosity for the variants identified in PTPRJ results in the almost complete loss of mRNA and protein. (A) Pedigree of the investigated family. Black symbols indicate thrombocytopenia. (B) PTPRJ mRNA expression in whole blood of the members of the family, as detected by real-time PCR. Expression is reported as fold change in PTPRJ relative to ACTB (β-actin) levels calculated with the ΔΔCt method. Data represent the means ± SD of 3 independent experiments using 3 HCs. (C-D) PTPRJ protein abundance in platelets from the members of the family. Lysates of washed platelets obtained from the 2 probands, their parents, and different HCs were analyzed by immunoblotting using an antibody against PTPRJ. β-actin was used as loading control. (C) Representative image of the immunoblotting experiments. (D) Densitometric analysis of the bands obtained in 3 independent experiments (means ± SD). PTPRJ level is expressed as the PTPRJ/β-actin ratio.