increased Lisch nodule incidence Lisch nodule MP:0006232 MPheno.ontology greater than the expected number of benign focal malformations in the iris in a specific population in a given time period; results from faulty iris development, and is composed of an abnormal mixture of tissue elements including melanocytes, or an abnormal proportion of a single element normally present at that site increased iris hamartoma incidence iris hamartoma increased iris tumor incidence increased hamartoma incidence