bleeding disorder, platelet-type, 22

Bleeding disorder, platelet-type, 22 is a condition that affects the normal function of platelets, leading to a tendency toward excessive bleeding even with minor trauma. The disorder is associated with changes in the EPHB2 gene, which plays a role in cell signaling important for normal platelet aggregation. It follows an autosomal recessive pattern, meaning that an affected individual typically inherits two altered copies of the gene, one from each parent. Precise prevalence estimates are not well established, and the condition is recognized through its characteristic bleeding features.

The clinical picture is dominated by impaired platelet aggregation, with patients almost universally exhibiting abnormal responses to platelet agonists such as ADP, arachidonic acid, and collagen. Excessive bleeding from superficial cuts, subcutaneous hemorrhages, and bleeding with minor or no trauma are consistently observed features. Some individuals may also experience thrombocytopenia and gastrointestinal hemorrhage, although these features occur less frequently. Not all individuals experience all features, and severity varies considerably.

The condition is caused by pathogenic variants in the EPHB2 gene, which is involved in critical cell signaling pathways that help regulate platelet function. Bleeding disorder, platelet-type, 22 is inherited in an autosomal recessive pattern, indicating that individuals must inherit two altered copies of the gene to develop the condition. This inheritance pattern also means that parents, who are usually carriers with one altered copy, generally do not show symptoms but may have a 25% chance of having an affected child with each pregnancy. Genetic counseling is recommended for families to understand the implications for family planning. Associated genes include EPHB2.