DXOMark's definition of the Low-light score: "Thus low-light ISO is the highest ISO setting for a camera that allows it to achieve an SNR of 30dB while keeping a good dynamic range of 9 EVs and a color depth of 18bits."
That is an arbitrary definition of the highest ISO that gives excellent image quality in an 8Mp print. DPReview don't use this criterion, so there is nothing to compare between the two sites in this regard.
Furthermore, they use two different definitions of ISO. DPReview use the standard definition in the industry, which is based on the brightness of out-of-camera JPEGs. This definition isn't applicable to unconverted raw files. It's the same definition that's used by the camera manufacturers. DXOMark, on the other hand, analyze unconverted raw files, and therefore use a definition of ISO based on sensor saturation.
This causes some confusion among people, who assume that all review sites measure the same thing. You often come across people accusing the camera makers of "cheating" with ISO, because ISO 1600 is really only ISO 800, for example. But they are comparing numbers measured in different ways, and there is really no cheating going on at all.
The point of all this is that DXOMark and DPReview coming to different conclusions about the ISO performance of a camera, is no cause for alarm, because they aren't talking about the exact same thing.