Pseudo-drumsticks in granulocytes of a male with a Yqh+ polymorphism.

An individual with normal male habitus, body proportions, and secondary sexual characteristics was admitted to the hospital with head trauma. A routine blood smear demonstrated that 36% of the granulocytes had "drumsticks". Chromosomal analysis revealed a 46,XYqh+ karyotype. the extremely large Y chromosome was located by quinacrine fluorescence in the "drumstick" of the polymorphonuclear granulocytes. The presence of a large Y chromosome may thus produce pseudo-drumsticks. Fluorescent staining can distinguish between true drumsticks bearing the inactive X of normal females and the pseudo-drumsticks in a normal male produced by a large Y chromosome.