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Two novel mutations of the γ‐secretase genes in Chinese acne inversa (hidradenitis suppurativa)

Acne inversa (AI, OMIM #142690), also called hidradenitis suppurativa (HS), is a chronic, inflammatory, recurrent and debilitating skin follicular disease that usually presents after puberty with painful, deepseated, inflamed lesions in the apocrine glandbearing areas of the body, most commonly the axilla, inguinal and anogenital regions. The estimated prevalence in Caucasian populations ranges from 0.1% to 1%1 but rarely reported in Chinese. About 35%– 40% of AI patients have a familial history, which shows an autosomaldominant inheritance pattern.2 In 2010, our group identified lossoffunction mutations in the NCSTN, PSENEN and PSEN1 genes in six Han Chinese families, thus first reported that haploinsufficiency of genes encoding γsecretase components as the genetic basis for familial AI.3 To date, over 40 mutations in γsecretase genes have been identified in familial AI patients from different populations, according to the Human Gene Mutation Database (HGMD, http://www. hgmd.cf.ac.uk/). In this letter, we reported two novel mutations in NCSTN and PSENEN in two Chinese AI families. Patient 1 is a 25yearold male presented with recurrent inflammatory papules, painful nodules, pustules, cysts and scars on the back of neck, axillae, back, upper chest, forearms and buttocks for 6 years (Figure 1A– F). With these clinical features, a diagnosis of acne inversa was made. He had been treated with isotretinoin without significant improvement. He