Sialic acids are components of carbohydrate chains of glycoconjugates and are involved in cell-cell recognition and cell-pathogen interactions. That protein has no CMP-N-acetylneuraminate monooxygenase activity and is not able to convert CMP-N-acetylneuraminic acid (CMP-Neu5Ac) into its hydroxylated derivative CMP-N-glycolylneuraminic acid (CMP-Neu5Gc), a sialic acid abundantly expressed at the surface of many cells in vertebrates (PubMed:9624188). However, it may play a role in Wnt signaling (PubMed:19890979). May localize to membranes, nucleus and cytoskeleton. Widely expressed. Highly expressed in thymus. Not expressed in brain. May be expressed in adult stem cells (at protein level) (PubMed:19890979). Belongs to the CMP-Neu5Ac hydroxylase family. An Alu-mediated mutation of this gene occured in a common ancestor of Homo sapiens and Homo sapiens neanderthalis, approximately 2.1-2.2 million years ago, before brain expansion. It is generally accepted that the product of this gene, if any, is catalytically inactive as suggested by the absence of CMP-Neu5Gc sialic acid in human, while it is abundantly expressed at the surface of many cells in other vertebrates. The gene is however, significantly transcribed and the product described here might be expressed in vivo (PubMed:19890979). The putative protein is N-terminally truncated compared to orthologs and lacks a region probably essential to the CMP-N-acetylneuraminate monooxygenase activity. Wrong choice of CDS.