We examine progranulin-knockout mice on two different genetic backgrounds.
•
Neuropathology in most brain regions is robust and penetrant on both backgrounds.
•
Microgliosis was more pronounced on the B6 background than on the 129 background.
•
Reduced hippocampal neuron number was observed on the B6 but not the 129 background.
•
Reduced spine density on hippocampal neurons was observed on the 129 background only.