PB1860 A TURKISH CHILD PRESENTED WITH NEONATAL THROMBOCYTOPENIA ASSOCIATED WITH GNE MUTATION WITHOUT ASSOCIATED MUSCLE WASTING

Abstract

Background:Mutations in the glucosamine (UDP‐N‐acetyl)‐2‐epimerase/N‐acetyl mannosamine kinase (GNE) gene have previously reported in children with myopathy, however, recently GNE gene mutations were reported to be causative in nine children with thrombocytopenia without associated muscle wasting.Aims:Here we share our experience of a child with macrothrombocytopenia without muscle wasting associated with GNE.Methods:The clinical and genetic features of child with GNE is reportedResults:A 30‐day‐old male was referred to Pediatric Hematology Clinic of Erciyes University with complaints of generalized petechial rash, ecchymoses just after birth and it was learned that he received intravenous immunoglobulin and platelet transfusions due to suspected neonatal allo‐immune thrombocytopenia at another medical center. His parents were first cousins. He was referred to our hospital NICU with thrombocytopenia. Blood count analyses revealed a hemoglobin of 10.6 g/dL, leukocyte count of 7810 x109/L, and platelet count of 6 x109 /L. The blood smear showed giant platelets. The bone marrow aspiration showed mild granulocyte maturation. He developed severe transfusion depended mucosal bleedings due to severe thrombocytopenia and neutropenia, so hematopoietic stem cell transplantation was planned. As no matching donor was found from the family or unrelated family, alpha beta depleted haploidentical hematopoietic stem cell transplantation (HSCT) from his father was performed. Although myeloid and platelet engraftments were achieved at +14, +13 days consequently, the chimerism decreased and the patient underwent a second haploidentical HSCT with mesenchymal stem cell support. Nevertheless, the chimerism did not improve and the patient died despite supportive treatment. Using whole exome sequencing, we identified a predicted pathogenic missense variant in the GNE gene (chr9:36219976:C>T, p.590:Gly>Arg) present in the heterozygous state in both parents and homozygous in the affected child.Summary/Conclusion:GNE mutations must be kept in mind for children with macrothrombocytopenia. Although our experience is limited, we speculate that there may be some underlying bone marrow micro‐environmental problem that resulted in early rejection after HSCT.