Familial thrombocytopenia due to a complex structural variant resulting ina WAC-ANKRD26 fusion transcript.
Wahlster, Lara and Verboon, Jeffrey M and Ludwig, Leif S and Black, Susan Cand Luo, Wendy and Garg, Kopal and Voit, Richard A and Collins, Ryan L andGarimella, Kiran and Costello, Maura and Chao, Katherine R and Goodrich,Julia K and DiTroia, Stephanie
Advances in genome sequencing have resulted in the identification of the causes for numerous rare diseases. However, many cases remain unsolved with standard molecular analyses. We describe a family presenting with a phenotype resembling inherited thrombocytopenia 2 (THC2). THC2 is generally caused by single nucleotide variants that prevent silencing of ANKRD26 expression during hematopoietic differentiation. Short-read whole-exome and genome sequencing approaches were unable to identify a causal variant in this family. Using long-read whole-genome sequencing, a large complex structural variant involving a paired-duplication inversion was identified. Through functional studies, we show that this structural variant results in a pathogenic gain-of-function WAC-ANKRD26 fusion transcript. Our findings illustrate how complex structural variants that may be missed by conventional genome sequencing approaches can cause human disease.
