Today in Nature Communications, scientists at the Institute for Research in Biomedicine (IRB Barcelona) provide molecular details about Seckel Syndrome, a rare disease that causes microcephaly, or small brain, and growth delays. A joint study conducted by Travis Stracker and Jens Lüders indicates that the protein CEP63 plays a key role during brain development as it is involved in the correct division of stem cells in this organ. Furthermore, the researchers have discovered that CEP63 is associated with sperm production—an unknown function until now.