ABCDEFGHIJKLMNOPQRSTUVWXYZIf the 1st, 3rd, 5th, 8th, 12th, 15th and 18th letters of the English alphabet (given above) are chosen to form a…

ABCDEFGHIJKLMNOPQRSTUVWXYZ

If the 1^st, 3^rd, 5^th, 8^th, 12^th, 15^th and 18^th letters of the English alphabet (given above) are chosen to form a meaningful word (name of a disease), which letter will come in the middle of all? Each letter must be used and only once.