Type I Glanzmann thrombasthenia: most common subtypes in North Indians

The expression of GPIIb/IIIa on the platelet surface was assessed in 10 patients with Glanzmann thrombasthenia and their families by flow cytometry to determine the common subtype in North Indians. Glanzmann thrombasthenia was diagnosed in patients with bleeding manifestations accompanied by absent/reduced platelet aggregation, secondary to ADP, ADR, arachidonic acid, and collagen. Flow cytometry revealed variable GPIIb/IIIa expression by CD61 and CD41 in patients with Glanzmann thrombasthenia on the basis of CD61 levels, six patients were subtyped as type I because they had absent GPIIb/IIIa, three patients were subtyped as type II because their GPIIb/IIIa levels varied from 7.72% to 20.40%, and one patient was diagnosed as type III, because his clot retraction was 60% and GPIIb/IIIa was 46.0% of normal. Four fathers, three mothers, and five siblings were found to have GPIIb/IIIa levels less than 35% of normal. It is possible that low GPIIb/IIIa levels in family members may reflect their carrier status. It is postulated that flow cytometric estimation of GPIIb/IIIa in parents/siblings may detect carrier status in Glanzmann thrombasthenia.