# Clinical and laboratorial characterization of a cohort of patients with hereditary platelet disorders in Brazil

## TL;DR

This study characterizes inherited platelet disorders in Brazil, highlighting diagnostic challenges and the importance of family history and lab tests.

## Contribution

The study provides a detailed clinical and laboratory profile of inherited platelet disorders in a Brazilian cohort, emphasizing diagnostic approaches in low-resource settings.

## Key findings

- Most patients had abnormal platelet function rather than thrombocytopenia.
- A significant proportion of patients had a positive family history of platelet disorders.
- Bleeding symptoms were generally mild, with low ISTH-BAT scores observed.

## Abstract

Inherited platelet disorders are rare conditions characterized by altered platelet function and/or reduced platelet counts. Diagnosing these disorders is challenging and may result in delays, misdiagnosis, and inappropriate treatment. In low- and middle-income countries, data are scarce. Here, we describe a cohort of patients at a reference center in Brazil.

A descriptive analysis was conducted on patients followed at the Thrombosis and Hemostasis outpatient clinic of the Hospital das Clinicas, University of São Paulo, Brazil.Medical records of 857 patients with thrombocytopenia or bleeding disorders of unknown cause, evaluated between 1998 and 2023, were reviewed. Of these, 60 patients had a confirmed or suspected diagnosis of an inherited platelet disorder and were included in the study.

Among the 60 patients, the majority were female (75 %), with a median age of 48 years. The suspicion of a platelet disorder was based on clinical presentation, family history, and laboratory findings. Overall, 65 % of the patients had abnormal platelet function, while 35 % presented with thrombocytopenia. A positive family history was reported in 62 % of those with low platelet counts and in 51 % of patients with platelet function abnormalities. Previous misdiagnoses included immune thrombocytopenia and von Willebrand disease. Overall, the bleeding phenotype was mild, with a median ISTH-BAT (International Society on Thrombosis and Haemostasis Bleeding Assessment Tool) score of 6. Patients with reduced platelet counts tended to have lower ISTH-BAT score.

Identifying inherited platelet disorders is essential for proper treatment and follow-up. This study emphasizes the need for careful assessment of family history, bleeding risk, platelet count, morphology, and function for diagnosis, particularly in low-resource settings without access to advanced genetic testing.