Duplication at Xq28 involving IKBKG is associated with progressive macrocephaly, recurrent infections, ectodermal dysplasia, benign tumors, and neuropathy

Abstract

Duplications on Xq28 are common, although quite variable in size, but usually include the MECP2 gene. Here, we present a patient with a unique, small, 167-kb duplication at Xq28, not including MECP2. The most important gene in the duplicated region was IKBKG, mutations in which can cause a variety of distinct syndromes. Our patient's symptoms overlapped with different IKBKG-associated phenotypes, including hypohidrotic ectodermal dysplasia, incontinentia pigmenti, immunodeficiency, recurrent isolated invasive pneumococcal disease and anhidrotic ectodermal dysplasia with immunodeficiency, osteopetrosis, and lymphedema. In addition, she also had peripheral neuropathy, gastroparesis and various benign tumors, but no intellectual disability. Mixed syndromal presentation in several patients with IKBKG defect implies that IKBKG-related phenotypes are more like a spectrum, rather than distinct syndromes. We also suggest our patient's multisystem phenotype to be a novel contiguous gene syndrome, in which the key features include immune deficiency, macrocephaly, skin abnormalities, gastroparesis, peripheral small-fiber neuropathy, and benign tumors.