MUTATIONS IN FAS ASSOCIATED WITH HUMAN LYMPHOPROLIFERATIVE SYNDROME AND AUTOIMMUNITY

Fas (also known as Apo1 and CD95) is a cell surface receptor involved in apoptotic cell death. Fas expression and function were analyzed in three children (including two siblings) with a lymphoproliferative syn drome, two of whom also had autoimmune disorders. A targe deletion in the gene encoding Fas and no detectable cell surface expression charac terized the most affected patient. Clinical manifestations in the two related patients were less severe: Fas-mediated apoptosis was impaired and a deletion within the intracytoplasmic domain was detected. These findings illustrate the crucial regulatory role of Fas and may provid e a molecular basis for some autoimmune diseases in humans.