The amount of a mannosyl-oligosaccharide 1,2-alpha-mannosidase IB (human) when measured in cerebrospinal fluid. The trait is level of mannosyl-oligosaccharide 1,2-alpha-mannosidase IB (human) in cerebrospinal fluid (OBA_2056237). Also known as: cerebrospinal fluid mannosyl-oligosaccharide 1,2-alpha-mannosidase IB (human) amount.