Authors

Alrun Hotz, Julia Kopp, Emmanuelle Bourrat, Vinzenz Oji, Kira Süßmuth, Katalin Komlosi, Bakar Bouadjar, Iliana Tantcheva-Poór, Maritta Hellström Pigg, Regina C. Betz, Kathrin Giehl, Fiona Schedel, Lisa Weibel, Solveig Schulz, Dora V. Stölzl, D Gianluca Tadini, Emine Demiral, Karin Berggard, Andreas D. Zimmer, Svenja Alter and Judith Fischer

Abstract

Autosomal recessive congenital ichthyosis (ARCI) is a non-syndromic congenital disorder of cornification characterized by abnormal scaling of the skin. The three major phenotypes are lamellar ichthyosis, congenital ichthyosiform erythroderma, and harlequin ichthyosis. ARCI is caused by biallelic mutations in ABCA12, ALOX12B, ALOXE3, CERS3, CYP4F22, NIPAL4, PNPLA1, SDR9C7, SULT2B1, and TGM1. The most severe form of ARCI, harlequin ichthyosis, is caused by mutations in ABCA12. Mutations in this gene can also lead to congenital ichthyosiform erythroderma or lamellar ichthyosis. We present a large cohort of 64 patients affected with ARCI carrying biallelic mutations in ABCA12. Our study comprises 34 novel mutations in ABCA12, expanding the mutational spectrum of ABCA12-associated ARCI up to 217 mutations. Within these we found the possible mutational hotspots c.4541G>A, p.(Arg1514His) and c.4139A>G, p.(Asn1380Ser). A correlation of the phenotype with the effect of the genetic mutation on protein function is demonstrated. Loss-of-function mutations on both alleles generally result in harlequin ichthyosis, whereas biallelic missense mutations mainly lead to CIE or LI.
Keywords:
ABCA12; ARCI; harlequin ichthyosis; lamellar ichthyosis; congenital ichthyosiform erythroderma