Question: What causes Harlequin ichthyosis ?
Answer: What causes harlequin ichthyosis? Harlequin ichthyosis is caused by mutations in the ABCA12 gene. This gene provides instructions for making a protein that is essential for the normal development of skin cells. This protein plays a major role in the transport of fats (lipids) in the outermost layer of skin (the epidermis). Some mutations in the ABCA12 gene prevent the cell from making any ABCA12 protein, while others lead to the production of an abnormally small version of the protein that cannot transport lipids properly. A loss of functional ABCA12 protein disrupts the normal development of the epidermis, resulting in the hard, thick scales characteristic of harlequin ichthyosis.
Source: GARD

Question: Is Harlequin ichthyosis inherited ?
Answer: How is harlequin ichthyosis inherited? Harlequin ichthyosis is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Source: GARD