In addition, a heterozygous truncating mutation in the colony-stimulating factor 1 receptor (CSF1R) gene, which encodes the macrophage colony-stimulating factor 1 receptor (M-CSF), was reported in the consanguineous parents of two deceased siblings showing osteopetrosis and brain malformations (Monies et al., 2017). Here, CSF1R is linked to osteopetrosis.