Cells: reduction in COG3 (50%), COG2 (40%), COG1 (25%), and COG5 (40%) protein levels, COG complex formation seemed to be unaffected, mild Golgi dysfunction (compared to COG7 or COG8‐CDG), Golgi dilatation and fragmentationPatients: Saul‐Wilson syndrome, a rare form of primordial dwarfism with characteristic facial and radiographic features. This evidence concerns the gene COG3 and isolated growth hormone deficiency type IA.