Background: Harlequin ichthyosis (HI) is a severe and rare autosomal recessive congenital ichthyosis, characterized by hyperkeratosis, extensive fissuring massive, diamond-shaped scales which limit the child’s movements. The term harlequin comes from baby’s facial expression pattern of like 17th century entertainers, harlequins. underlying genetic abnormality has been identified as mutation in ...

Harlequin syndrome (HS) is a rare disorder of the sympathetic nervous system which presents with unilateral decreased sweating and flushing of the face, neck, and chest in response to heat, exercise, or emotional factors. The contralateral side displays a compensatory overreaction to provide normal heat regulation of the face as a whole. In the literature, most of the cases are primary in natur...

Harlequin ichthyosis (HI), which is the most severe genodermatosis, is caused by loss-of-function mutations in ABCA12, a member of the ATP-binding cassette transporter family. To investigate the pathomechanism of HI and the function of the ABCA12 protein, we generated ABCA12-deficient mice (Abca12(-/-)) by targeting Abca12. Abca12(-/-) mice closely reproduce the human HI phenotype, showing mark...