She is the Director of the Human Genome Research Center at the Biological Institute of the University of São Paulo and together with her group has published more than 200 peer-reviewed scientific articles, most of them related to neuromuscular disorders. Her group helped to identify six of the genes responsible for neuromuscular diseases. Mariana Zatz coordinated one of the laboratories which was involved in the Xylella Genome project at the Institute. She is also responsible for genetic counseling at the University at São Paulo, which has assisted more than twenty thousand people from families with neuromuscular diseases and has helped to diagnose and prevent the birth of children affected by serious irreversible illnesses. In 1981 she founded the Brazilian Association of Muscular Dystrophy (ABDIM), for poor children, where patients undergo physiotherapy, hydrotherapy, occupational therapy and other activities which can improve their quality of life.