A Case of Incontinentia Pigmenti in Japan and Its Genetic Examination

Abstract

Incontinentia pigmenti (IP) is a rare X-linked dominant genodermatosis with approximately one-third of cases with associated ocular complications. Deletion of exons 4 to 10 of the nuclear factor kappaB essential modulator (NEMO) gene accounts for the majority of new mutations. The disease is more commonly found among Caucasians. We studied a case of an IP patient in Japan, and the genomic rearrangements. An 11-month-old female infant exhibited the skin lesions of IP. Ocular findings were total retinal detachment with a retrolental fibrovascular mass in the right eye, and patchy retinal avascular zones and neovascularization in the left eye. The genomic rearrangement of NEMO was investigated by a polymerase chain reaction (PCR)-based diagnostic test. A skewed X-inactivation assay was also performed using the human androgen receptor gene as a genetic marker. Deletion of exons 4 to 10 in NEMO was detected in the proband and in other female members of her family. A complete skewing of the X-inactivation pattern causing IP was observed, indicating cells having no protection against apoptosis in response to tumor necrosis factor as the pathogenicity of the disease. This is the first case report of a Japanese female phenotype demonstrating the common genomic rearrangement in the NEMO gene.