The name ichthyosis comes from the Greek word for "fish" because sufferers can have dry, scaly skin. The HARLEQUIN Baby disease or congenital ichthyosis of the Harlequin fetus type is an orphan genetic disease that mainly affects babies and young children Harlequin Ichthyosis is a very rare genetic disease with an estimated prevalence of less than 1/1000,000 associated with significant morbidity (<50%) and mortality shortly after birth. Diagnosis is based on clinical examination (brown, scaly and very dry skin making it difficult for the baby to move), skin biopsy and analysis.