Genotyping was carried out using 250k and 6k SNP microarrays in order to perform homozygosity mapping and copy number variation (CNV) analysis. Targeted NGS was performed to identify the genetic defect in this family. qPCR was performed to validate and confirm the NGS result.
Homozygosity mapping positioned the causative defect on chromosome 2p25.3-p25.2. Subsequent targeted NGS revealed an intragenic deletion of five exons of the gene TPO.
NGS is a powerful method to uncover submicroscopic structural variations. This result demonstrates that an unbiased screening approach such as NGS can help to?identify even unexpected disease-causing mutations.