Stephen L. Hauser is a professor of the Department of Neurology at the University of California, San Francisco (UCSF) specializing in immune mechanisms and multiple sclerosis (MS).

In 2007, as a senior organizer of the International Multiple Sclerosis Genetics Consortium (IMSGC), he helped identify the first two non-HLA genes involved in MS susceptibility, IL-2R (CD25) and IL-7R (CD127).

[3] In 2010, his laboratory published the complete genome sequences and the epigenome of identical twins discordant for MS. By mid-2011 more than fifty MS-associated risk alleles were identified, and by now nearly the entire array of common variants associated with MS susceptibility have been mapped.

He led a large-scale clinical trial with rituximab,[5] a chimeric monoclonal antibody that depletes CD20+ B cells, and demonstrated robust efficacy in relapsing remitting MS. A second trial in primary progressive MS reported in 2009 that rituximab may be similarly effective in patients with primary progressive MS who also have evidence of ongoing inflammatory CNS disease.

More recently, a third clinical trial with a fully humanized anti-CD20 monoclonal antibody, ocrelizumab, replicated the results of the rituximab trial in relapsing remitting MS.[6] With the MS Bioscreen project, Hauser has pioneered precision medicine for complex diseases like MS, creating an "actionable digital growth-chart for complex traits" [7] In 2010 Hauser was appointed to the Presidential Commission for the Study of Bioethical Issues.