Second trimester prenatal diagnosis in Glanzmann's Thrombasthenia

How I manage pregnancy in women with Glanzmann thrombasthenia

Glanzmann thrombasthenia (GT) is a rare inherited platelet function disorder caused by a quantitative and/or qualitative defect of the αIIbβ3 integrin. Pregnancy and delivery is a recognized risk period for bleeding in women with GT. The newborn may also be affected by fetal and neonatal immune thrombocytopenia induced by the transplacental passage of maternal anti-αIIbβ3 antibodies, which can lead to severe hemorrhage and fetal loss. Pregnancy in GT women thus requires a multidisciplinary approach, including prepregnancy counseling, and a treatment plan for delivery for both the mother and child. In this article, we summarize the current knowledge on pregnancy in women with GT and describe how we manage this severe platelet disorder in our clinical practice.

Glanzmann Thrombasthenia: Perspectives from Clinical Practice on Accurate Diagnosis and Optimal Treatment Strategies

Glanzmann thrombasthenia (GT) is a rare autosomal recessive disorder of fibrinogen-mediated platelet aggregation due to a quantitative or qualitative deficit of the α_IIbβ₃ integrin at the platelet surface membrane resulting from mutation(s) in ITGA2B and/or ITGB3. Patients tend to present in early childhood with easy bruising and mucocutaneous bleeding. The diagnostic process requires consideration of more common disorders of haemostasis and coagulation prior to confirming the disorder with platelet light transmission aggregation, flow cytometry of CD41 and CD61 expression, and/or exon sequencing of ITGA2B and ITGB3. Antifibrinolytic therapy, recombinant activated factor VII, and platelet transfusions are the mainstay of therapy, although the latter may trigger formation of anti-platelet antibodies in GT patients and inadvertent platelet-refractory disease. The management of these patients therefore remains complex, particularly in the context of trauma, labour and delivery, and perioperative care. Bone marrow transplantation remains the sole curative option, although the venue of gene therapy is being increasingly explored as a future alternative for definitive treatment of GT.

Identification of Three Novel Mutations in the FANCA, FANCC, and ITGA2B Genes by Whole Exome Sequencing

Background

Various blood diseases are caused by mutations in the FANCA, FANCC, and ITGA2B genes. Exome sequencing is a suitable method for identifying single-gene disease and genetic heterogeneity complaints.

Methods

Among families who were referred to Narges Genetic and PND Laboratory in 2015-2017, five families with a history of blood diseases were analyzed using the whole exome sequencing (WES) method.

Results

We detected two novel mutations (c.190-2A>G and c.2840C>G) in the FANCA gene, c. 1429dupA mutation in the FANCC gene, and c.1392A>G mutation in the ITGA2B gene. The prediction of variant pathogenicity has been done using bioinformatics tools such as Mutation taster PhD-SNP and polyphen2 and were confirmed by Sanger sequencing.

Conclusions

WES could be as a precise tool for identifying the pathologic variants in affected patient and heterozygous carriers among families. This highly successful technique will remain at the forefront of platelet and blood genomic research.