abnormal late pro-B cell, abnormal locomotor activation, abnormal lymphopoiesis, absent B-2 B cells, absent late pro-B cells, absent mature B cells, arrested B cell differentiation, decreased B-1 B cell number, decreased B-1b cell number, decreased body size, decreased IgG1 level, decreased IgG2a level, decreased IgG2b level, decreased IgG3 level, decreased immature B cell number, decreased inferior colliculus size, decreased mature B cell number, decreased pre-B cell number, domed cranium, hearing/vestibular/ear phenotype, immune system phenotype, impaired humoral immune response, increased anxiety-related response, increased B-1 B cell number, increased cardiac muscle contractility, increased CD4-positive, CD25-positive, alpha-beta regulatory T cell number, increased CD8-positive, alpha-beta memory T cell number, increased macrophage cell number, increased single-positive T cell number, lethality at weaning, complete penetrance, limb grasping, no abnormal phenotype detected, postnatal lethality, incomplete penetrance, premature death, preweaning lethality, complete penetrance