Analysis of IKBKG/NEMO gene in five Japanese cases of incontinentia pigmenti with retinopathy: fine genomic assay of a rare male case with mosaicism.

Incontinentia pigmenti (IP) is an X-linked dominant genodermatosis that is usually lethal in utero in males, though exceptionally they survive very rarely either with Klinefelter syndrome or a somatic mosaicism. We performed genomic analysis of five Japanese IP patients including a rare boy case, all of whom were definite cases with retinopathy. Four patients including the boy revealed the recurrent exon 4-10 deletion in the sole known causative gene IKBKG/NEMO, which was confirmed by various specific PCR techniques. The boy's saliva DNA showed a mosaicism consisting of the deletion and intact alleles, but his blood DNA did not. Relative quantification analysis of the real-time PCR data by ∆∆CT method estimated the mosaicism ratio of the boy's saliva as 45:55 (deletion:intact). A genomic analysis for the recurrent deletion at the nucleotide sequence level has been performed directly using patient's DNA and it has been clarified that the breakpoints are within two MER67B repeats in the intron 3 and downstream of exon 10. This is the first report of the assay for the mosaicism ratio of a male IP case with a recurrent exon 4-10 deletion of IKBKG/NEMO and the sequencing analysis of the breakpoints of the recurrent deletion directly using patient's sample.

Early laser photocoagulation for extensive retinal avascularity in infants with incontinentia pigmenti.

PURPOSE: To describe the clinical features and treatment outcomes of severe retinopathy in eyes with incontinentia pigmenti (IP) of infants within a few months of birth. STUDY DESIGN: Retrospective clinical study. METHODS: Six eyes of three patients (6-day-old girl, 5-month-old girl, and 14-day-old boy) with IP were examined and treated under general anesthesia. Ophthalmologic examinations were performed including images from wide-angle fluorescein angiography (FA), swept-source optical coherence tomography (OCT), and OCT angiography (OCTA). RESULTS: Ophthalmoscopy showed prominent vascular tortuosity in five eyes, retinal hemorrhages in four eyes, and incomplete vascular development in two eyes. FA showed extensive avascularity including the posterior pole of the retina in all cases except one eye. Prompt and intensive laser photocoagulation stabilized the pre-proliferative severe retinopathy in five eyes; however, foveal structure and vessel anomalies were detected in three of six eyes by OCT and two of five eyes by OCTA. CONCLUSION: Severe retinopathy in the neonatal period and infancy was present not only in the periphery but also in the posterior pole including the fovea, which might be related to retinal vascular maldevelopment. It is, therefore, recommended that wide-angle fundus FA examination be performed in the early postnatal period to detect early signs of severe retinopathy in infants with IP.