Your Query returns 4 Accession Numbers:

Query TermAccessionNCBI TaxonidSynonymsPhenotype (OMIM) *
H2a-615NM_01354910090Hist2    Hist2h2aa1   
H2a-615NM_0035169606H2A    H2A.2    H2A/O    H2AFO    HIST2H2AA   
H2a-615BC06225510090Hist2h2aa1   
H2a-615U6267410090

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

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Text2Knowledge ... Yong Huang 2002