Analysis of progeny showed that mice heterozygous (HE) and homozygous knock-in (KI) for the knock-in mutation were viable but with a skewed Mendelian segregation in the offspring of HE breeders at 21 days of life (27% WT (n=1,172), 51% HE (n=2,252), 22% apo-sGC (n=987); χ2=17.5; P<0.001). Here, SGCB is linked to hereditary elliptocytosis.