TODAY | April 01, 2013
>>> we're back now at 7:43 with a medical mystery in north carolina . 4-year-old boy living there keeps suffering from strokes, which are commonly thought to be an adult condition. and it's his courage that caught our attention. here's nbc's gabe gutierrez.
>> reporter: like most little boys his age, calen arthur loves fire trucks .
>> oh, yeah! yeah!
>> reporter: with the flashing lights and sirens, it's no mystery. but 4-year-old calen is a mystery.
>> every test we've done to try to identify a cause of stroke has come up normal.
>> reporter: in the last two years, calen has suffered so many strokes his doctors can't count them. six major ones have left him blind in his left eye and weakened on his right side. he's had to relearn how to walk several times.
>> he is the inspiration of myself and a lot of other people.
>> reporter: tony arthur is calen's dad a retired army veteran, now a firefighter near raleigh.
>> there's nothing about him that has the word quit in it.
>> reporter: aelon has endured so many tests he can't pronounce and so many drugs --
>> this one, this one, this one --
>> reporter: that it's hard for his mom gen toifr keep track.
>> did i miss anything? i think we got them all.
>> reporter: while caelon's doctors work to find the cause of the strokes caelon is working on being a 4-year-old and inspiration. what do you think people much older than him can learn from him in.
>> anything is possible.
>> never give up.
>> reporter: for "today," gabe gutierrez, nbc news, roseville, north carolina .