Autoimmune lymphoproliferative syndrome type III: An indefinite disorder

Autoimmune Lymphoproliferative Syndrome (ALPS) is a childhood disorder char acterized by chronic nonmalignant lymphoproliferation and autoimmunity. Alt hough the pathogenesis is not fully understood. deficient Fas mediated apop tosis appears to be an important factor. This deficiency can be caused by a mutation of the: APT1 gene (ALPS type Ia), of the FasL gene (ALPS type Ib) . or of the Caspase-10 gene (ALPS type II). In one sub population of patien ts, no mutations have been identified as: yet (ALPS type III). According to published data, the latter group is much smaller than the group of patient s with ALPS type Ia. However. because of the variability of the clinical pr esentation and the absence of a known genetic defect, this disease is diffi cult to diagnose, the more so as few data have been reported on these patie nts. Thus, ALPS type III could be more common than believed until now. In t his review we provide evidence for this hypothesis.