One of the diseases related to cone cells present in retina is Retinoblastoma. Retinoblastoma is a rare, cancerous tumor of a part of the eye called the retina. Cancer of the retina common in children which is caused by the mutation of both copies of retinoblastoma genes (RB1)., the protein encoded by RB1 regulates a signal transduction pathway while controlling the cell cycle progression as normally. The scientists have come to a conclusion that retinoblastoma seems to originate in cone precursor cells present in the retina that consist of natural signalling networks which restrict cell death and promote cell survival after losing the RB1. It has been found that TRβ2 which is a transcription factor specifically affiliated with cones is essential for rapid reproduction and existence of the retinoblastoma cell.<ref name="Tumorigenesis: Cone cells set the stage">{{cite journal|last=Skinner|first=Mhairi|title=Tumorigenesis: Cone cells set the stage|journal=Nature Reviews Cancer|date=August|year=2009|volume=9|pages=534|doi=10.1038/nrc2710|accessdate=12 April 2012}}</ref> The drug that will be useful in the treatment of this disease is MDM2 (murine double minute 2) gene. Some of the symptoms include:
-One or both eyes may be affected.
-They pupil may appear white or have white spots. A white glow in the eye is often seen in photographs taken with a flash. Instead of the typical "red eye" from the flash, the pupil may appear white or distorted.
