Chanika Phornphutkul

Sep 25, 2023 | mdpi.com | Jake Littman |John Pietro |Jon Olansen |Chanika Phornphutkul

1. IntroductionOchronosis, named in reference to the Greek word “ochre” meaning “earthy” or “yellowed in appearance,” is a rare disorder that presents primarily as discolored blue-black or grey-blue pigmentation of the skin, cartilage of the ears, and sclerae [1]. Endogenous ochronosis is synonymous with alkaptonuria (AKU, OMIM 203500), which has also been called “black urine disease,” since the urine collected from those affected turns black upon standing.