Only managers can delete gene databases from LOVD. Below the gene's detailed view, click the "Delete gene" link. To complete the removal, you will need to fill in your password twice.
Please note that besides the loss of all variants within this gene database, also all patients that will have no variants left, will be deleted. So a patient with only variants in the deleted gene will be removed, but a patient who also has variants from other genes, will remain but will of course lose the variants from the removed gene.