22/01/2026
Waardenburg syndrome
affects the eyes due to defective neural crest cell migration during embryonic development, resulting in a reduced or absent number of melanocytes in ocular tissues, particularly the iris stroma and choroid. Normally, these melanocytes produce melanin that determines eye color and absorbs excess light. However, when they fail to develop or migrate properly, the iris becomes hypopigmented, leading to very pale blue eyes or heterochromia. The migration defect may be asymmetrical, explaining why only one eye may be affected. Unlike albinism, melanin synthesis itself is normal, and retinal development, including the fovea, is usually preserved, so visual acuity is often normal despite the striking eye appearance. 👀👓💡🔬
