NF-κB essential modulator (NEMO) is a kinase integral to the macrophage TNF-α pathway, which leads to the intracellular destruction of Mycobacteria species. Defects in the NEMO pathway result in spectrum of diseases, including but not limited to ectodermal dysplasia, Mendelian susceptibility to mycobacterial diseases, and incontinentia pigmenti. In addition, paucity of NEMO can lead to the inability to mount a proper immune response against opportunistic pyogenic and mycobacterial infections, leading to dissemination to various organ systems. This manuscript will discuss the numerous clinical manifestations of NEMO deficiency, the differential diagnosis of atypical mycobacterial infections in immunocompetent adults, and feature a case report of rare isolated susceptibility to disseminated atypical mycobacteria due to a mutation in the first exon of the NEMO gene.