NEFL and atrial fibrillation: Particularly, the genes coding for neurofilament light polypeptide (NEFL) and neurofilament 4 (PRPH) (markers for small axons) showed significantly higher mRNA abundances in AF compared with skin (18.4 and 4.4-fold higher), muscle (6.4- and 1.3-fold higher), liver (41.2- and 2.9-fold higher) and HK (8.6- and 1.7-fold higher).