There seems to be some ambiguity regarding MRC1 and MRC1L1.
If you query BioMart using MRC1 and ask for Agilent probes as an attribute, you get A_23_P12746, as suggested previously. If you query using MRC1L1 you get 2 results: one with A_23_P12746 as a probe, the other a different transcript with no probe.
The gene card for MRC1L1 states that it lies very close to MRC1, on chromosome 10, in a duplicated region.
Searching at UCSC browser throws up 2 UCSC genes named MRC1, close to each other and 4 Refseq genes (2x MRC1, 2x MRC1L1), in apparently identical positions.
Here are the results of the BioMart queries:
Ensembl Gene ID Ensembl Transcript ID Agilent WholeGenome HGNC ID HGNC symbol Chromosome Name Transcript Start (bp) Transcript End (bp)
ENSG00000120586 ENST00000239761 A_23_P12746 7228 MRC1 10 18098352 18200091
ENSG00000183748 ENST00000331429 A_23_P12746 23403 MRC1L1 10 17851362 17953178
ENSG00000183748 ENST00000457317 23403 MRC1L1 10 17851362 17896832
This indicates that there are 2 MRC1L1 transcripts and the probe maps to one of them, as well as to the MRC1 transcript.