The SLC27 gene family code for fatty acid transport proteins (FATPs). Long chain fatty acids (LCFAs) are critical for many physiological and cellular processes as a primary energy source. Of the six FATPs characterised, three have been shown to mediate the influx of LCFAs into cells; FATP1, 4 and 6. SLC27A4 (FATP4) is the major intestinal LCFA transporter but is also expressed at lower levels in brain, kidney, liver and heart. SLC27A4 is also expressed in skin, where it has been shown to play a major role in epidermal development, being highly expressed in neonatal keratinocytes. Defects in SLC27A4 can cause ichthyosis prematurity syndrome (IPS; MIM:604194), a keratinisation disorder which is characterised by thickened epidermis and respiratory complications with patients suffering from a lifelong non-scaly ichthyosis. Patients with IPS show a severe skin phenotype, a defective permeability barrier function and perturbed VLCFA metabolism. Mutations that can cause IPS include C168*, S247P, Q300R, R583H and A92T (Klar et al. 2009).