[ensembl-dev] Multiple NM numbers per transcript

[Wolf Beat]

Hi everybody.

I have a probably trivial question, but as a computer scientist some details in genetics sometimes get lost on me;)

So, when i wanted to find out the NM number of TP53-001, i saw that this transcript has many different NM numbers:
http://grch37.ensembl.org/Homo_sapiens/Transcript/Summary?db=core;g=ENSG00000141510;r=17:7571720-7590856;t=ENST00000269305

What is strange to me, is that when i look at their details, they look different:
http://www.ncbi.nlm.nih.gov/nuccore/NM_000546
http://www.ncbi.nlm.nih.gov/nuccore/NM_001126112

Those are two examples of NM numbers associated with TP53-001, but from what i understand those are clearly not the same transcript.

Am i missing something important? What would the correct NM number be for this transcript and how can i determine which one it is?

Kind regards

Beat Wolf