Epicanthic fold Epicanthic fold The epicanthic fold is the skin fold of the upper eyelid, covering the inner corner (medial canthus) of the eye. Various factors influence whether epicanthic folds form, including ancestry, age, and certain medical conditions. The highest frequency of occurrence of epicanthic folds are found in: East Asians, Southeast Asians, Central Asians, North Asians, some South Asians, Polynesians, Micronesians, Indigenous Americans (as well as Mestizos), the Khoisan, Malagasy. In some of these populations the trait is almost universal. Epicanthic folds occur, but at considerably lower frequency, in: Europeans (e.g., Scandinavians, English, Irish, Hungarians, Russians, Poles, Lithuanians, Finns, Estonians and
Thioredoxin fold the first cysteine. Human proteins containing this domain include: Thioredoxin fold The thioredoxin fold is a protein fold common to enzymes that catalyze disulfide bond formation and isomerization. The fold is named for the canonical example thioredoxin and is found in both prokaryotic and eukaryotic proteins. It is an example of an alpha/beta protein fold that has oxidoreductase activity. The fold's spatial topology consists of a four-stranded antiparallel beta sheet sandwiched between three alpha helices. The strand topology is 2134 with 3 antiparallel to the rest. Despite sequence variability in many regions of the fold, thioredoxin proteins share a common