Identification of novel RASGRP2 mutations in patients with platelet dysfunction.

Inherited platelet function disorders (IPFDs) are rare hereditary diseases characterized by dysregulation of genes related to platelet receptors expression or signal transduction pathways. Bleeding disorder platelet-type 18 (BDPLT18) is an infrequent autosomal recessive platelet function disorder caused by RASGRP2 mutation. The RASGRP2 gene encodes calcium- and DAG-regulated guanine exchange factor-1 (CalDAG-GEFI), which plays a role in the activation of the αIIbβ3 integrin in platelets. In present study, eleven unrelated patients were examined for mutational analysis to identify mutations in RASGRP2 gene that may lead to BDPLT18. The study included 11 unrelated cases (6 males and 5 females) with various bleeding disorders in 2024. The patients were selected based on normal expression of CD41, CD61, and CD42b, as well as an impaired response to ADP, collagen, and arachidonic acid. The plasma coagulation parameters of the patients were normal. Polymerase chain reaction (PCR) and sanger sequencing were used to screen for mutations in the RASGRP2 gene. A total of 7 mutations were identified in the patients. Including four novel missense mutations (RASGRP2: p.F497L, p.F501L, p.N505K, p.C515G) and 3 known mutations (RASGRP2: p.D441N, p.R494Afs*54, g.10410 G>T). These mutations are predicted to cause disease and alter the characteristics of the CalDAG-GEFI protein. Identifying RASGRP2 gene mutations and their association with bleeding episodes is crucial for confirming the diagnosis of BDPLT18, distinguishing it from other platelet disorders, and using effective therapeutics to prevent bleeding abnormalities.