We also mapped a micronucleus QTL at this locus, that contains only three genes within its 95% CI, including Slc7a1. Mice carrying a homozygous deleterious mutation of this gene die of anemia at birth with 50% fewer red blood cells and reduced hemoglobin levels (Perkins et al. 1997). The gene discussed is SLC7A1; the disease is anemia.