Here's some information from the AAMC (Association of American Medical Colleges) about medical students who have disabilities:
The Americans with Disabilities Act (ADA) has afforded new rights and protections to persons with disabilities and heightened public awareness of the needs of this population. This handbook (published in 1993) provides an overview of the ADA and the antecedent Rehabilitation Act of 1973. It is intended to assist medical schools in the review and refinement of institutional policies. It is not intended as a comprehensive treatment of all the issues that might arise under the ADA or the Rehabilitation Act, no is it intended to provide legal advice. Schools should consult legal counsel regarding any specific questions about particular situations or decisions.You can read the full document here (PDF)
The purpose of the ADA is to provide opportunities for persons with disabilities to compete with other applicants on the basis of their ability. Like the Rehabilitation Act, the ADA requires many entities—including medical schools—to provide certain accommodations to persons with disabilities so that they may enjoy the same benefits, services and opportunities as those without disabilities. Schools must judge persons on the basis of their ability to complete the educational program rather than on their status as disabled persons. Persons seeking admission must be able to perform the "essential functions" or meet the "essential eligibility requirements" of the program once they have been provided with any needed accommodation or modification. Each school must determine the "essential functions" or "essential eligibility requirements" of its educational program. Preadmission inquiry as to whether a person is disabled is not permitted, but a school may seek as much information as is needed to make a determination that an individual can perform the "essential functions" or meet the "essential eligibility requirements" of the educational program.
In 2005, the AAMC published an updated version of this document, Medical Students with Disabilities: A Generation of Practice, which includes a discussion of ADA-related case law generated since the early 1990s.