This is an autosomal dominant disorder that maps to a locus on chromosome 20 (20p11.2-q11.2). The molecular defect remains unknown. It is of interest that the posterior polymorphous corneal dystrophy 1 (PPCD1, 122000) mutation has been mapped to the same pericentric region, and it has been suggested that the two conditions may be allelic. These are now combined into a single entity in OMIM.
This disorder should not be confused with congenital endothelial dystrophy type 2, CHED2 (217700) which is autosomal recessive, has an earlier presentation, and maps to a different region of chromosome 20. Harboyan syndrome (217400) has similar corneal features but maps to a different location on chromosome 20 and is associated with sensorineural deafness.
The nosology of the corneal dystrophies is still evolving. In the 2015 edition of the IC3D, this condition designated CHED1 is eliminated based on clinical and pathologic similarities to those in posterior polymorphous corneal dystrophy 1 (PPCD1, 122000). However, while the loci for PPCD2 and CHED1 are located in the same pericentric region of chromosome 20, the purported mutations occur in different genes.