Abstract: 【Abstract】 Objective To investigate clinical characteristics and genetic variations in a case of self-improving collodion ichthyosis in the adult stage. Methods An adult patient with clinically suspected self-improving collodion ichthyosis was collected from the Department of Dermatology, Henan Provincial People′s Hospital in April 2023. Clinical data were collected from the patient and her parents. Peripheral blood samples were obtained from them, and whole blood DNA was extracted. Whole-exome sequencing was performed to screen genetic variation sites, which were then verified by Sanger sequencing. The deleteriousness of the identified variants was assessed using pathogenicity analysis software. Results The 54-year-old female patient presented with facial and neck flushing, mild dry skin on trunk and limbs, sheepskin-like skin of the dorsal hand, and short fingers. Genetic testing showed that two in-frame deletion mutations c.406_408del （p.E136del） and c.769_801del （p.H257_Q267del） were identified in the non-repetitive region of the ALOX12B gene in the patient, which were inherited from her father and mother respectively. Bioinformatics analysis revealed that both genetic variation sites were deleterious pathogenic mutations. Conclusions Two in-frame deletion mutations c.406_408del （p.E136del） and c.769_801del （p.H257_Q267del） were identified in the non-repetitive region of the ALOX12B gene in the patient with self-improving collodion ichthyosis, which may contribute to the clinical phenotype of the patient. The mutation c.769_801del had not been reported in literature.

Key words: Ichthyosiform erythroderma, congenital, Autosomal recessive congenital ichthyosis, ALOX12B gene, Genetic variation