Abstract: 【Abstract】 Objective To identify mutations in the NEMO gene in a family with incontinentia pigmenti. Methods Clinical data were collected from the proband, and peripheral blood samples were obtained from the proband, her parents and 200 healthy controls. Multiplex PCR was performed to detect heterozygous deletion of exons 4 - 10 of the NEMO gene in the blood samples of the proband and her parents. Then, PCR was performed to amplify exons 2, 3 - 10 of the NEMO gene in all the blood samples, and all exons in the gene coding region and their flanking sequences were subjected to DNA sequencing. DNA was extracted from paraffin?embedded lesional tissue of the proband′s father, and PCR was performed to amplify exon 10 of the NEMO gene and its flanking sequence followed by DNA sequencing. Results The deletion of exons 4 - 10 of the NEMO gene was undetected in the peripheral blood of the proband or her father. Sanger sequencing showed that there was a heterozygous mutation c.1236dupA in exon 10 of the NEMO gene in the peripheral blood of the proband, which led to a mutation in amino acid residues（p. H413fs*7）. The c.1236dupA mutation was not found in the peripheral blood of the proband′s parents, while a mosaic mutation c.1236dupA was detected in the DNA from lesional tissues of the proband′s father. Conclusion The mutation c.1236dupA in the NEMO gene may be the underlying cause of incontinentia pigmenti in the proband and her father.

Key words: Incontinentia pigmenti, DNA mutational analysis, Mosaicism, Skin manifestations, NEMO gene