A Case of Incontinentia Pigmenti in Japan: Clinical Manifestations and Genetic Examination

Abstract

Abstract: : Purpose: Incontinentia pigmenti (IP) is a rare X–linked dominant genodermatosis with approximately one third associated with ocular complications. IP results from mutations in the gene coding for NF–kappaB essential modulator (NEMO). The deletion of exons 4–10 of NEMO accounts for the majority of new mutations. Despite the establishment of the genomic rearrangement in NEMO among Caucasians, this is poorly confirmed in the Japanese population. We here report a Japanese female infant with IP caused by mutation in the NEMO gene along with ocular manifestations. Methods: An eleven–month–old female infant exhibited typical IP findings as hyperkeratotic lesions neonatally. No family history of IP was detected. Ocular examinations revealed a total retinal detachment with retrolental fibrovascular mass in the right eye and patchy retinal avascular zone and neovascularization in the left eye. Treatments of fundus photocoagulation in the left and vitreous surgery in the right were performed. Responsible genetic aberrations were searched by a PCR–based diagnostic method for the genomic rearrangement in NEMO. Skewed X–inactivation assay was also performed using human androgen receptor gene as a genetic marker. Results: Deletion of exons 4 though 10 in the NEMO gene, a common genomic rearrangement was detected in this patient. A complete skewing of X–inactivation pattern causing IP was also observed indicating the apoptosis of cells having no protection against cell death as a pathogenicity of the disease. Conclusions: This is the first report from Japan demonstrating a severe clinical ocular manifestation associated with the common genomic rearrangement in NEMO gene.

Keywords: retinal degenerations: hereditary • genetics