Compound heterozygous ABCA12 mutations including a novel nonsense mutation underlie harlequin ichthyosis.

[harlequin ichthyosis]

Recently , it has been reported that several harlequin ichthyosis (HI ) patients survive the neonatal period and their condition subsequently improves . Here we describe a 2 -year -old Japanese boy who exhibited typical clinical features of HI at birth . He survived beyond the neonatal period after oral retinoid treatment and , at the age of 2 years , showed moderately thick , lamellar scales and erythroderma over his whole body . The patient is a compound heterozygote for 2 ABCA 12 mutations , a paternal deletion mutation c .2021 _2022 del (p .Lys 674 ArgfsX 63 ) and a novel maternal nonsense mutation c .7444 C --> T (p .Arg 2482 X ). Electron microscopic observation of a skin biopsy specimen from the perinatal period revealed epidermal ultrastructural features consistent with HI . Immunofluorescence labeling using antiserum against a C-terminal ABCA 12 epitope showed loss of expression in the patient 's epidermis . The present patient demonstrates that rapid diagnosis of HI by ABCA 12 expression analysis and mutation detection , and early commencement of systemic retinoid therapy are crucial to significantly improving an HI patient 's prognosis .