The House Subcommittee on Civil Rights and Civil Liberties will hear testimony Wednesday from Boston-area medical and legal experts about the impact the end of "medical deferred action" may have on seriously ill patients from around the world.

Massachusetts U.S. Rep. Ayanna Pressley will be part of the emergency hearing aimed at uncovering the reasoning behind the Trump administration's moves to quietly phase out the humanitarian process that allowed seriously ill immigrants to apply to remain in the U.S. for medical treatment.

Members of Congress will hear from 16-year-old Jonathan Sanchez, a resident of Dorchester who's from Honduras. Sanchez and his family have been living in Boston since 2016 after entering the country on tourist visas. Earlier he told WBUR he receives life-saving treatment for cystic fibrosis at Boston Children's Hospital.

Mariela and Gary Sanchez, and their son Jonathan, who receives treatment for cystic fibrosis at Boston Children’s Hospital. (Robin Lubbock/WBUR)

Last month, he and his family were notified by the federal government that they needed to leave the country within 33 days because medical deferred action requests were no longer being processed.

Officials with U.S. Citizenship and Immigration Services (USCIS), as well as Immigration and Customs Enforcement (ICE), are expected to face tough questioning during Wednesday's hearing around the end of the program.

After facing significant pushback from members of the public and Congress, USCIS announced it would reopen a number of cases, including Sanchez's, that were pending as of Aug. 7.

Pressley has been particularly vocal about the fact there were no public announcements from the Trump administration, and no opportunity for the public to comment on the program's elimination.