I have researched the Clendenin family pretty extensively. Isaac Clendenin is NOT part of the John Clendenin family, whom connects with the Huston and Sharron/Sharon families.
John Clendenin's land was located in the extreme northwest of Silver Spring, in the angle formed by Stony Ridge and the mountain. He owned the land by the improvements he made – settling on the property, building a cabin, working the farm – not by warrant or patent. Samuel Huston and John Clendenin were brothers-in-law: John was married to Janet Huston, Samuel's sister. They had these children: Jonathan, John, Margaret, William, Jennie, Mary, Annie, Isabella and James Clendenin.
There are NO Isaac Clendenin sons in any of the families.