Purpose The LZTR1 gene has been associated with schwannomatosis tumour predisposition and is located in a region that is deleted in the great majority (89%) of patients with 22q11.2 deletion syndrome (22q11.2DS). Since it is known that approximately 1 in 500 people in the general population will develop a sporadic schwannoma and there are no reports of the occurrence of schwannoma in 22q11.2DS, we investigated whether whole gene deletion of LZTR1 occurs in schwannomatosis and assessed the risk of schwannoma in 22q11.2DS.
Methods We assessed the genetic testing results for LZTR1-associated schwannomatosis and the clinical phenotypes of patients with 22q11.2DS.
Results There were no reports of schwannoma in over 1500 patients with 22q11.2DS. In addition, no patients meeting clinical diagnostic criteria for schwannomatosis had a whole gene deletion in LZTR1. Only one patient in 110 with an apparently sporadic vestibular schwannoma had a constitutional whole gene deletion of LZTR1.
Conclusion People with a large 22q11.2 deletion may have a reduced risk of developing a schwannoma compared to the general population.