A Novel Frameshift Mutation of the IKBKG Gene Causing Typical Incontinentia Pigmenti

Incontinentia pigmenti (IP) is a rare X-linked dominant genodermatosis. Mutations of the IKBKG gene are responsible for IP. A deletion of exons 4-10 can be found in 80% of patients with IP. There are 69 different mutations of the IKBKG gene that have been reported.

A proband, female patient from a family without previously diagnosed IP is reported. She had skin and dental changes typical of IP. The diagnosis was made according to updated IP criteria. Pathohistological and ultrastructural analysis of skin biopsy confirmed the diagnosis. However, the common deletion of exons 4-10 in the IKBKG gene could not be detected. Sequencing revealed the indel (deletion/insertion) mutation c.641_647delGCATGGAinsAT (p.Arg214HisfsX38) in exon 5 of the IKBKG gene. Because this mutation could not be detected in the unaffected mother of the proband, it seems to be a de novo mutation.

The registered novel frameshift/KBKG mutation c.641_647delGCATGGAinsAT (p.Arg214HisfsX38) can be considered to be the cause of IP in this case.