Complex sentence: Individuals with TRAPS have a mutation in the tumor necrosis factor receptor-1 (TNFR1) gene, the mechanisms by which mutations in TNFR1 lead to the TRAPS phenotype are still unknown.
Split into simpler sentences: Individuals with TRAPS have a mutation in the tumor necrosis factor receptor-1 (TNFR1) gene. The mechanisms by which mutations in TNFR1 lead to the TRAPS phenotype are still unknown.