Two lawsuits have been filed against the U.S. Social Security Administration challenging the U.S. government's policy of refusing to provide Supplemental Security Income (SSI) disability benefits to American citizens living on Guam.

The lawsuits were filed on behalf of twin sisters Katrina Schaller of Barrigada, Guam; and Leslie Schaller of Greensburg, Pennsylvania. The two complementary federal cases were filed simultaneously on Thursday in both Guam and Pittsburgh, Pennsylvania.

The sisters are 48 years old. Each lives with myotonic dystrophy, a debilitating, degenerative genetic disorder that severely inhibits muscle function and other critical aspects of daily life.

Although Leslie Schaller is able to live independently in Pennsylvania due to the aid she receives from SSI, Katrina is ineligible for the same SSI benefits received by her twin because she lives on Guam with her older sister and brother-in-law.

The sisters are being represented at no cost by the Washington, D.C., law firm Kirkland & Ellis. It's the world's largest law firm, according to the American Lawyer.

According to a release from the law firm, the SSI law limits benefits to American citizens who live "in the United States," which is defined in the law as being the 50 states, the District of Columbia and the Commonwealth of the Northern Mariana Islands, but not Guam.

Attorney Rodney Jacob of Calvo Fisher & Jacob filed the Guam lawsuit.

"It is contrary to common sense, human decency and sound public policy ... to deny public benefits to Katrina Schaller and all other American citizens with disabilities living on Guam."

Jacob argues that the SSI law violates the Constitution's guarantee of "equal protection" under the Fifth and Fourteenth Amendments, as well as violating the Organic Act of Guam.

The lawsuit seeks a declaration from the court that the SSI law is discriminatory, and asks for an injunction against the Social Security Administration ordering the agency to provide the same benefits to Guam residents that it provides to all other American citizens.