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.

色素失禁（IP）是X连锁的显性遗传皮肤病，通常在男性子宫内致死，尽管异常情况下，无论是克氏综合征还是体细胞镶嵌症，它们都很少存活。我们对五名日本IP患者进行了基因组分析，包括一个罕见的男孩病例，所有这些病例都是视网膜病变的明确病例。包括男孩在内的四名患者在唯一已知的致病基因IKBKG / NEMO中发现复发性外显子4-10缺失，已通过各种特定的PCR技术得到证实。该男孩的唾液DNA显示出由缺失和完整等位基因组成的镶嵌，但他的血液DNA没有。通过∆∆CT方法对实时PCR数据进行的相对定量分析估计，男孩唾液的镶嵌率为45:55（删除：完整）。已使用患者的DNA直接在核苷酸序列水平进行了基因组重复缺失的基因组分析，并且已明确断点位于内含子3和外显子10下游的两个MER67B重复序列内。这是该方法的首次报道IKBKG / NEMO的外显子4–10缺失的男性IP病例的镶嵌率，并直接使用患者样品对复发缺失的断点进行测序。