Epicanthus is a condition in which a fold of skin stretches from the upper to the lower eyelid, partially covering the inner canthus. Usher (1935) noted that epicanthus is a normal finding in the fetus of all races. Epicanthus also occurs in association with hereditary ptosis (110100).
Dominant inheritance of epicanthus was demonstrated in many pedigrees reviewed by Usher (1935).
Hu (1983) found epicanthus and epiblepharon of the upper eyelid and of the lower eyelid to be frequent among Chinese students: 38.1, 37.8, and 10.0%, respectively. He investigated 254 pairs of twins. The concordance rates were nearly 100% in monozygotic twins and in dizygotic twins were close to those expected of an autosomal dominant trait. Thus, all 3 traits are probably autosomal dominant.
Hu, D.-N. Ophthalmic genetics in China. Ophthalmic Paediat. Genet. 2: 39-45, 1983.
Usher, C. H. Pedigrees of hereditary epicanthus. Biometrika 27: 5-25, 1935.