Your Query returns 2 Accession Numbers:

Query TermAccessionNCBI TaxonidSynonymsPhenotype (OMIM) *
p49/p100NM_01940810090lyt    p49    p52    p50B    NF-kappaB2    Nfkb2   
p49/p100BC02742310090lyt    p49    p52    p50B    NF-kappaB2    Nfkb2   

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* OMIM link based on symbol match for human and mouse.

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Text2Knowledge ... Yong Huang 2002