It was supposed to be a special day -- one that Nancy Coyne and her terminally ill son Garrett would always remember. They will remember the day they went to see Santa at the mall, however, it will be for all the wrong reasons.

When Nancy and Garrett returned to the car, which was parked in a designated handicapped area, she found a note scrawled in lipstick on her window:

"UR Not Handicap"

"I can’t believe someone could be so obnoxious and ignorant and rude about a situation that I struggle with daily," Coyne tells Fox 29.

Garrett suffers from Batten Disease, a rare neurological disorder that is fatal 100% of the time. He's already gone blind, and his cognitive, emotional, and motor skill will continue on a downhill slide.

I'm particularly disgusted by this story as my life has been touched by this insidious disease. Clifford, the older son of one of my dearest friends was diagnosed with Batten Disease 14 years ago when he was just six years old. You can read more about his journey and find out more about this rare, deadly disease here.

Nancy Coyne says the incident has made her question society and says her anger has now turned to sadness "for the person who obviously needs a lesson on tolerance."