Congenital macrothrombocytopenia associated with a combination of functional polymorphisms in the TUBB1 gene.

Congenital thrombocytopenia in childhood and adolescence requires an extensive diagnostic workup to find the underlying reason. We report on a 13-year-old female patient who was incidentally found to have moderate thrombocytopenia which was also diagnosed in her father and brother. Within the microscopic evaluation of a peripheral blood smear macrothrombocytes were found. Immunofluorescence microscopy of the patient's platelets detected the lack of β1-tubulin. Analysis of the TUBB1 gene revealed three known missense variants in heterozygous state which in combination might explain the β1-tubulin defect.