Which gene is associated with X-linked disorders leading to eczema, recurrent infections, and thrombocytopenia?

The gene associated with X-linked disorders that lead to eczema, recurrent infections, and thrombocytopenia is the WAS gene. This gene encodes for the Wiskott-Aldrich syndrome protein, which is involved in the signaling processes of hematopoietic (blood-forming) cells, particularly affecting immune function.

Individuals with mutations in the WAS gene present with a classic triad of symptoms: eczema, which manifests as itchy and inflamed skin; recurrent infections stemming from immune deficiency; and thrombocytopenia, characterized by low platelet counts leading to increased bleeding risks. The X-linked inheritance pattern explains why the condition predominantly affects males, with females being carriers without typically exhibiting severe symptoms.

The other genes listed are associated with different genetic disorders. USH2A is linked to Usher syndrome, which affects hearing and vision; COL11A1 is related to some types of stickler syndrome affecting connective tissue; and GJB2 is commonly associated with non-syndromic hearing loss. Each of these genes does not have the same association with the specific triad of symptoms mentioned in the question. Thus, the WAS gene is definitively the correct answer due to its direct involvement in the described clinical manifestations.