Sadly, little Louis-Philippe died not long before his first birthday, on May 16, 1834. His father was devastated; the loss revived all his painful memories of the death in childbirth of his first wife, Princess Charlotte Augusta of Wales and their son. According to Patrick Weber in Amours royales et princières, Leopold even began to imagine he was under a curse and thought he might have to appoint a nephew as heir to the Belgian throne (I have to admit I have some doubts about the first part of this claim. Given Leopold's essentially coolheaded and pragmatic personality, it is a bit hard to envisage him brooding over dynastic maledictions). Nonetheless, the King was consoled by the birth of his second son, Leopold (future Leopold II) in 1835.
Today, the mortal remains of the first Crown Prince of Belgium rest with those of his parents in the Royal Crypt of the Church of Our Lady in Laeken.
(*the drawing depicts Louise-Marie with one of her children, I don't know which child it is but I needed some sort of picture with a baby!)