VPS16B null platelets appear abnormal in blood films. Romanowsky (Wright-Giemsa)–stained blood films from a VPS16B-deficient ARC patient compared with a neonatal control visualized using oil-immersion 63×/1.4 objective lenses. (A) VPS16B null platelets appeared large, homogeneous, pale and nongranular (arrows). (B) Normal neonatal control platelets are typically smaller, and granular (arrows).