Intrafamilial clinical variability in four families with incontinentia pigmenti.

Incontinentia Pigmenti (IP) is an X-linked rare genodermatosis caused by mutations in the IKBKG gene, which is essential to NF-κB pathway activation and thus fundamental for cell survival. Our objective was to study the intrafamilial clinical variability in IP by investigating how the signs of IP, and especially dental anomalies, vary within affected families. Four families, encompassing a total of 15 IP familial cases, were included in the study. The patients were subjected to clinical examination and collection of family histories for assessment of intrafamilial clinical variability. All familial cases carried the IKBKGdel recurrent deletion. A noticeable intrafamilial clinical variability was observed in all studied families, with mild and severe cases co-occurring within a same family. Additionally, to best of our knowledge, our study was the first to address the variability of dental defects within IP families, and here too, our results reveal remarkable differences among affected relatives. A number of as yet unidentified genes might act as modifiers, influencing disease expressivity. Our study found important clinical variability within four IP families and contributes to the understanding of the genetic background involved in IP expressivity.