Definition:

Retinal dystrophy, iris coloboma, and comedogenic acne syndrome (RDCCAS) is an early onset, progressive, and severe autosomal recessive retinitis pigmentosa. It is characterized by developmental abnormalities including patent ductus arteriosus and chorioretinal and iris colobomas. Some developed severe acne. In addition, the patients exhibited severe vitamin A deficiency, and diminished serum retinol levels. A homozygous splice site variant in the gene encoding retinol binding protein (RBP4) has been identified. RBP4 is the carrier of retinol in human plasma and is involved in transport of retinol from liver to peripheral tissue including the retina.