_:vb50954578 . _:vb50954578 . _:vb50954578 "An immune system disease that results when one or more essential parts of the immune system is missing or not working properly at birth due to a genetic mutation."^^ . _:vb50954578 . _:vb50954578 . _:vb50954578 "url:http://www.nichd.nih.gov/publications/pubs/primary_immuno.cfm#PrimaryImmunoDiseases"^^ . _:vb50954578 .