Dr. Ballabio's impact on human genetics research began with his discoveries of X-linked disease genes. His contributions have spanned an enormous range of human diseases and biological processes, from X-inactivation (XIST), axonal targeting (Kallmann syndrome), and melanosome biogenesis (ocular albinism) to mitochondrial biogenesis (hereditary spastic paraplegia), post-translational protein modification (multiple sulfatase deficiency), and the role of autophagy in lysosomal storage diseases to name a few. He led a large international project, EurExpress, to build an expression atlas for all murine genes. The Ballabio lab has identified many genes and pathogenetic mechanisms that have led to a number of successful therapeutic tests in animal models, which are now moving to preclinical trials. The lab's discovery of the SUMF1 gene, for example, had a direct impact on the production of active sulfatases for enzyme replacement therapy.