OBJECTIVE: To analyze clinical manifestation and gene of NF-kappaB essential modulator (NEMO) in 12 pediatric incontinentia pigmenti (IP) patients. METHODS: Twelve pediatric probands with three of their mothers were enrolled in this study. Physical examinations were undertaken for all patients and questionnaires requesting additional medical and developmental data were sent to the patients' families. The deletion of exon 4-10 and all 10 exons of NEMO gene were analyzed in these cases. Skin biopsy was performed in one case. RESULTS: All 15 patients had skin pigmentation abnormality and were diagnosed according to classic skin lesions. The prevalence of the dental, neurologic system, hair abnormality, and definite family history were 80.0%, 41.67%, 58.33%, and 25.0%, respectively. Histopathological examination was consistent with the diagnosis of IP with ectodermal dysplasia. In NEMO gene, deletion of exons 4-10 were noted in three cases and two of their mothers. A deletion of 19545 T in exon 6 was noted in one case and her mother. A 21690 T to C mutation in intron 8 of NEMO were found in another one case and her mother. CONCLUSION: The results suggest that skin lesion are the most prominent findings in clinics and the traditional diagnosis of IP is based on classic melanin pigmentation. Nucleotide deletion of exons 4-10 and single nucleotide mutation/polymorphism were found in these patients, which might account for etiopathogenesis of IP.