DS-epi2−/− mice do not show any evident phenotype 22. The brain was analyzed because DS-epi2 is the predominant epimerase in this tissue 22,31. Accordingly, DS-epi2−/− brains had a 90% reduction in epimerase activity. The brains of newborn mice contain little IdoA (2% of the total chain), and this was further reduced in DS-epi2−/− mice. However, the brain extracellular matrix (ECM) architecture was unaltered. It would be interesting to determine whether more subtle phenotypes such as behavioural changes are present in DS-epi2−/− mice.
