An alternative hypothesis for iris maldevelopment (aniridia).

ABSTRACT

Two principal hypotheses for the pathogenesis of hypoplastic iris development ("aniridia") have been proposed 1) the ectodermal theory, positing incomplete elaboration of the cup, resulting in an absence of framework for further development; and 2) the "mesodermal" theory, wherein inadequate migration or proliferation of mesenchymal elements is proposed. Two eyes of two patients with persistent "anterior leaf" iris strand remnants which traverse the pupillary space are reported. They are differentiated from the previously described persistent tunica vasculosa lentis. The presence of a persistent pupillary iris strand suggests portions of the iris may have formed and inappropriately regressed. Recent work in cell biology highlights the importance of remodeling and cell death in revealing ultimate phenotypic expression. This alternative hypothesis suggests that aniridia may be explained in part on the basis of excessive remodeling and cell death.