Marie Unna hereditary hypotrichosis accompanied by multiple familial trichoepithelioma in a Chinese family

Abstract

Marie Unna hereditary hypotrichosis (MUHH) and multiple familial trichoepithelioma (MFT) are both autosomal dominant disorders. Recently, certain genes (HR and EPS8L3) have been found to be responsible for MUHH, while CYLD has been demonstrated to be the main pathogenic gene in MFT patients. However, there exist a number of CYLD mutation‐negative MFT cases, for which the causative gene has been unknown. Here, we identified a large, five‐generation Han Chinese family with several patients presenting with MUHH and MFT. Sanger sequencing of three genes in 13 family members was performed. We found that the c.1A>G mutation in an inhibitory upstream open‐reading frame of HR (U2HR) was present in all MUHH patients, while no pathogenic variants were found in the 3ʹ‐ or 5ʹ‐untranslated regions, exons or flanking intronic sequences of EPS8L3 or CYLD in any family members. Subsequently, whole‐genome sequencing was performed for five affected and one unaffected family member. We found no CYLD variants but identified an FABP12 variant (rs536105592 G>A) in the patients with both MUHH and MFT. These results suggest that the U2HR mutation was responsible for MUHH and the FABP12 variant may be coincidental in the accompanying MFT in this unique pedigree. This report deepens our understanding of the genetic basis of hair follicle diseases.

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