Ring chromosome 12 with inverted microduplication of 12p13.3 involving the Von Willebrand Factor gene associated with cryptogenic stroke in a young adult male.

We report a 35-year-old male with a ring chromosome 12 originally diagnosed 20 years prior to presentation with an ischemic stroke. Array CGH analysis revealed a sub-microscopic microdeletion and microduplication within 12p13.3 and a microdeletion in 12q24.33. FISH analysis further revealed that the duplication was in an inverted orientation and included exons 35-52 of the dosage-sensitive Von Willebrand Factor (VWF) gene. Partial duplication of this gene, which has a role in the clotting cascade, suggests a potential mechanism for generating a pro-thrombotic state that may have contributed to a premature cerebrovascular event. Evidence of raised VWF antigen levels and VWF activity levels in the highest quartile provides support for this hypothesis. This case illustrates that when a ring chromosome is identified, the possibility of cryptic genomic rearrangements needs to be considered as these may have implications in predicting natural history.