New Research Highlights Rare Coexistence of Glanzmann Thrombasthenia & von Willebrand Disease
August 11, 2026
A new 2026 research letter describes an extremely rare case of a patient diagnosed with both Glanzmann thrombasthenia (GT) and von Willebrand disease (VWD).
The patient was diagnosed with GT at age five after experiencing bleeding symptoms beginning in infancy. Later, she developed recurrent gastrointestinal bleeding. At age 20, a severe GI bleed did not respond adequately to platelet transfusion, prompting additional testing that revealed reduced von Willebrand factor and led to a diagnosis of VWD.
Two Separate Genetic Findings
Researchers identified separate genetic abnormalities affecting two different parts of the body’s ability to control bleeding.
Testing found an ITGA2B mutation responsible for her GT and a separate VWF variant associated with VWD. Laboratory experiments showed that the VWF variant interfered with normal secretion of von Willebrand factor.
The patient also experienced severe gastrointestinal bleeding associated with intestinal angiodysplasia, which eventually required surgery. The researchers believe the combination of GT and VWD may have contributed to her severe bleeding, although they emphasize that the contribution of each disorder remains unclear.
What Does This Mean for the GT Community?
This case does not suggest that people with GT commonly have VWD. Reports of the two conditions occurring together are exceptionally rare.
Instead, the researchers highlight a broader lesson: when someone with a known platelet disorder experiences bleeding that is persistent, disproportionate, or unusual, it may be worth investigating whether another bleeding abnormality is contributing.
Because this research involves only one patient, it cannot tell us how frequently GT and VWD coexist or whether these findings apply to the broader GT community.
The study was supported by Japanese government research organizations, and the authors reported no competing interests.