Original studies of this strain, first published in 1996, describe homozygous animals that died within 21 days of birth and exhibited several novel pathogenic phenotypes including severe anemia, degeneration of neurons in the basal ganglia and brainstem, progressive motor disturbances, and myocardial injury. Applications included studies of idiopathic cardiomyopathy and sporadic motor neuron disease.
It has been found, however, that mice homozygous for the Sod2tm1Leb mutation on the current C57BL/6 genetic background (backcross generation N5+25 - July, 2017) are embryonic lethal. In one recent study, heterozygote x heterozygote crosses produced no homozygous mutants at P0-P1 (0/40 pups; unpublished).
Improved homozygous viability has been demonstrated in matings of B6.129S7-Sod2tm1Leb/J (Stock# 002973) mutant mice with DBA/2J inbred animals (Stock# 000671). Intercrosses of F1 animals yield F2 homozygous pups at a lower-than-predicted Mendelian percentage, but they have a median survival time of 12 days. The C57BL/6-DBA/2J (B6D2F2) mixed background mutant animals (not currently offered by The Jackson Laboratory) display severe wasting and progressive ataxia. The heart and brain have not been examined histologically. This data has not been published (July, 2017).
