anterior segment dysgenesis (MONDO_0019503) is a spectrum of developmental anomalies that affect the development of the anterior segment of the eyeball resulting from abnormalities of neural crest migration and differentiation during embryologic development (Axenfeld-Rieger syndrome, Peters anomaly, posterior keratoconus, and iridoschisis). Also known as: ASGD, ASMD, ASOD, anterior segment mesenchymal dysgenesis, anterior segment ocular dysgenesis, familial ocular anterior segment mesenchymal dysgenesis.