Open AccessNext-Generation Sequencing Based Approach to Identify Underlying Genetic Defects of Glanzmann Thrombasthenia
Author(s) -
Ritika Sharma,
Manu Jamwal,
Hari Kishan Senee,
Varun Uppal,
Jasbir Kaur Hira,
Parveen Bose,
Narender Kumar,
Deepak Bansal,
Amita Trehan,
Pankaj Malhotra,
Jasmina Ahluwalia,
Reena Das
Publication year - 2020
Publication title -
indian journal of hematology and blood transfusion/indian journal of hematology and blood transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.213
H-Index - 15
eISSN - 0974-0449
pISSN - 0971-4502
DOI - 10.1007/s12288-020-01368-8
Subject(s) - sanger sequencing , genetics , nonsense mutation , thrombasthenia , missense mutation , compound heterozygosity , glanzmann's thrombasthenia , platelet disorder , gene , loss of heterozygosity , medicine , biology , dna sequencing , phenotype , platelet , allele , platelet aggregation
Glanzmann thrombasthenia (GT) is an autosomal recessive platelet function disorder characterized by mucocutaneous bleeding as the most common clinical phenotype. Patients with GT have normal platelet counts, platelet morphology but reduced platelet aggregation in response to various agonists. Homozygosity or compound heterozygosity for variants in the ITGA2B/ITGB3 genes is the genetic basis for GT. Establishing a molecular diagnosis is definitive and is important for predictive testing. Using multi-gene panels is an accurate, faster, and cost-effective mode as compared to Sanger sequencing in large genes. We used a targeted resequencing based approach to identify pathogenic variants in eight cases in seven families. These variants were validated using Sanger sequencing in patients as well as family members and were predicted probably pathogenic using in-silico prediction tools. The variants include three missense (3/7 = 43%) ( ITGA2B: c.1028 T > C, ITGA2B: c.1186G > A, ITGB3: c.1388G > C), two deletions ( ITGA2B: c.559delG, ITGA2B: c.3092delT), one duplication ( ITGA2B: c.1424_1427dupAGGT) and nonsense variant ( ITGA2B: c.2578C > T, p.Gln860Ter). Except for one case which was compound heterozygous, the rest of the cases were homozygous. We found two novel variants that are reported for the first time in GT. The targeted resequencing based approach revealed varied genetic variants in North Indian patients, including two novels ones. The high yield of our panel indicates its suitability for usage in larger cohorts for the genetic diagnosis of GT patients. This approach is cost-effective and less cumbersome as compared to Sanger sequencing for these large size genes with multiple exons. The information so obtained is helpful in prenatal testing, carrier analysis, and genetic counseling.