Harlequin Fetus- A severe form of ichthyosis
Harlequin ichthyosis is rare and severe form of ichthyosis characterized by excessive keratinization of the skin and results in a grotesque appearance. This is inherited in an autosomal recessive pattern due to a mutation in the ABCA 12 gene. This gene is involved in the transport of epidermal lipids and is required for normal skin development. The affected infants are born with very hard, thick skin covering most of their bodies. There is massive thickening of the keratin layer which cracks to form fissures between large diamond shaped plaques, resembling fish scales. Such infants have severe ectropion (outward turning of eyelids) which leaves the eye at risk of dessication. Affected neonates may also have poorly developed nose and ears. Traction of the lip causes eclabium (outward turing of the lips). The extremities are also affected leading to contractures and the hyperkerotic skin covering the limbs restricts movements. The inextensible skin of the chest can lead to restricted movement and respiratory failure. The thickened skin serves to prevent normal sweat gland function and heat loss. The affected children experience excessive water loss and suffer from life threating infections due to disruption of the skin barrier. Image via: https://images.app.goo.gl/PtFwBmHP2zYiZsMn9