Platelet Delta (δ)-Storage Pool Deficiency: A Case Series and Review of the Literature

Abstract

Hereditary platelet delta (δ)-storage pool deficiency is a rare condition in which there are fewer dense granules in platelets disrupting primary hemostasis. It can cause a mild–moderate bleeding tendency with normal coagulation studies; hence, it is an underdiagnosed diagnostic challenge. The authors present three patients with hereditary platelet delta (δ)-storage pool deficiency who had heavy menstrual bleeding, excessive bleeding following surgery, mucocutaneous bleeding, and a bleeding score greater than or equal to 6. These cases reveal the susceptibility of underdiagnosing platelet disorders and the significance of utilizing a bleeding assessment tool to help guide further workup with transmission electron microscopy to visualize the fewer dense granules in platelets. Although bleeding is typically moderate, it can be severe in certain scenarios, like after mucosal surgeries, and can lead to death, highlighting the importance of the condition’s recognition and prophylactic treatment.

Platelet-Rich Plasma in Dermatology: New Insights on the Cellular Mechanism of Skin Repair and Regeneration

“…The dense granules (δ-granules) are platelet-specific organelles. They are smaller (approximately 150 nm) and numerically less abundant than the α-granules [153,154]. The δ-granules arise from the early endosomal network, concomitantly with the α-granules [155], and contain serotonin, histamine, uracil, guanine nucleotides, serotonin, calcium, potassium, and polyphosphates [156].…”

“…The molecules stored within dense granules are involved in thrombosis and blood homeostasis. The δ-granules' deficiency usually affects bleeding, by affecting platelet aggregation and thrombus formation (thus increasing the bleeding tendency) [153,160,161]. Moreover, serotonin is marked by both vasodilator and vasoconstrictor properties, and is an important player in vascular tone regulation in humans [162].…”