Health & Environmental Research Online (HERO)


Print Feedback Export to File
7380187 
Journal Article 
A new mutation in exon 7 of NEMO gene: late skewed X-chromosome inactivation in an incontinentia pigmenti female patient with immunodeficiency 
Martinez-Pomar, N; Munoz-Saa, I; Heine-Suner, D; Martin, A; Smahi, A; Matamoros, N 
2005 
Yes 
Human Genetics
ISSN: 0340-6717
EISSN: 1432-1203 
118 
3-4 
458-465 
English 
16228229 
WOS:000234542900017 
Incontinentia pigmenti is an X-linked genodermatosis, lethal in males. Affected females survive because of X-chromosome dizygosity and negative selection of cells carrying the mutant X-chromosome, and for this reason the skewed X inactivation pattern is often used to confirm the diagnosis. The most frequent mutation is a deletion of part of the NEMO gene (NEMODelta4-10), although other mutations have been reported. Mutations of NEMO which do not abolish NF-kappaB activity totally permit male survival, causing an allelic variant of IP called hypohidrotic ectodermal dysplasia and immunodeficiency (HED-ID). We present a non-classical IP female patient who also suffered transient immunodeficiency because of a late and progressive selection against peripheral blood cells carrying an active mutated X-chromosome. This finding suggests that in the absence of known mutation the X-inactivation studies used in genetic counselling can induce mistakes with some female patients. At the age of 3 years and 6 months, all immunodeficiency signs disappeared, and the X-chromosome inactivation pattern was completely skewed. The low T cell proliferation and CD40L expression corroborate the important role of NEMO/ NF-kappaB pathway in T cell homeostasis. The decreased NEMO protein amount and the impaired IkBalpha degradation suggest that this new mutation, NM_003639: c.1049dupA, causes RNA or protein instability. To our knowledge, this is the first time that selection against the mutated X-chromosome in X-linked disease has been documented in vivo.