Structure–Function Relationships of the CMP-Sialic Acid Transporter through Analysis of a Pathogenic Variant in an Alternatively Spliced Functional Isoform - Brenda I. Velázquez-Dodge; Marco A. Ramírez-Martínez; Nina Pastor; Iván Martínez-Duncker; Yobana Pérez-Cervera; Héctor M. Mora-Montes; Blanca E. Domínguez-Mendoza; Roberta Salinas-Marín (ACS Omega)