macular corneal dystrophy
macular corneal dystrophy
macular corneal dystrophy
An autosomal recessive condition (OMIM:217800) characterised by progressive minute, grey, punctate corneal opacities of early onset, usually between age 5 and 9. Corneal sensitivity is usually reduced, accompanied by pain, photophobia, foreign body sensation, and recurrent erosions.Subtypes
• MCD type I—Virtual absence of keratan sulfate in the serum and cornea, as determined by KS-specific antibodies, due to a homozygous missense mutation.
• MCD type II—Normal KS-antibody response in cornea and serum, due to a large deletion and replacement in the upstream region of CHST6.
Molecular pathology
Defects in CHST6, which encodes a sulfotransferase that maintains corneal transparancy, cause macular corneal dystrophy.