[Name] Barclay's Protomorphosis Syndrome [Source] Star Trek: The next Generation [Symptoms] 
A viral infection that causes an infected person to "de-evolve". Caused by a synthetic T-cell which mistakenly activated entrons in one's system. Named for Lt. Reginald Barclay who first contracted the disease when he was administered the synthetic T-cell due to a genetic condition which left own inactive. Said synthetic T-cell caused all dormant entrons to activate rather than the defective T-cell.