All of the associated ocular and systemic anomalies appeared to arise from the maldevelopment of the neural crest cells. Patients with Axenfeld-Rieger syndrome should therefore be examined for the presence of anomalies in the tissues of neural crest origin. Patients with hypoplasia of the iris should be checked for glaucoma.

Aims-To clarify the developmental mechanism and critical period for the uncommon complex of Peters' anomaly and persistent hyperplastic primary vitreous (PHPV). Methods-Two eyes with Peters' anomaly and PHPV were histologically examined by serial section. One eye was enucleated at age 7 months (case 1) and the other at age 4 months (case 2) owing to severe anterior staphyloma. Results-In both eyes, defects in the endothelium, Descemet's membrane, and posterior stroma were observed in the central cornea, and the degenerative lens adhered to the posterior surface of the defective corneal stroma. Also, in both eyes, the anterior chamber space was not formed and the undiVerentiated iris stroma adhered to the posterior surface of the peripheral cornea. Mesenchymal tissue containing melanocytes was observed behind the degenerative lens, and the pigment epithelium was absent at the lower nasal side of the ciliary body in case 1. In case 2, mesenchymal tissue containing scattered melanocytes in the vitreous cavity was seen on the posterior retina. Based on the histological findings, both cases were diagnosed as Peters' anomaly caused by the faulty separation of the lens vesicle, PHPV, maldevelopment of the iris and ciliary body, and goniodysgenesis. Conclusion-Migratory disorders of neural crest cells from 4 to 7 weeks of gestation may be responsible for various ocular anomalies including Peters' anomaly and PHPV, as observed in these cases.

Peters' anomaly accompanying corneolenticular adhesion and/or other ocular anomalies should be evaluated for the presence of systemic anomalies.

Axenfeld-Rieger syndrome is inherited in an autosomal dominant pattern and is characterized by anomalies of the anterior segment of the eye and systemic signs including craniofacial dysmorphic features and cardiac defects. The disorder is genetically heterogeneous and one causative gene, FOXC1, is located on chromosome 6p25. Persistent hyperplastic primary vitreous (PHPV) is a congenital ocular disorder in which there is a failure of the normal regression of the primary vitreous and a proliferation of fibrous tissue from the remnants of the primary vitreous. Deletions of chromosome 6p25 have been reported in a small number of patients with Axenfeld-Rieger syndrome; however, no case of chromosome 6p25 deletion has been reported with PHPV. We report a newborn girl who had both Axenfeld-Rieger syndrome and the combined type of PHPV, in whom the G-banding and spectral karyotyping revealed a 6p monosomy of terminal deletion with a breakpoint at chromosome 6p25.1. The karyotype was 46,XX,del(6)(p25.1). We conclude that PHPV in the context of Axenfeld-Rieger syndrome can be caused by 6p25 terminal deletion.

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