BBB	Blood–Brain Barrier
IDS	Iduronate 2-Sulfatase
GAG	Glycosaminoglycan
LC-MS/MS	Liquid Chromatography-Tandem Mass Spectrometry
HS	Heparan Sulfate
DS	Dermatan Sulfate
CSF	Cerebrospinal Fluid
FACS	Fluorescence-Activated Cell Sorting
TfR	Transferrin Receptor
LOD	Limit of Detection
LLOQ	Low Limit of Quantification
MPS II	Mucopolysaccharidosis II
ETV	Enzyme Transport Vehicle
D0A0	4,5 unsaturated uronic acid residue-N-acetyl glucosamine, HS ∆UA-GluNAc
D0S0	4,5 unsaturated uronic acid residue-glucosamine-N-sulfate, ∆UA-GluNS
D0a4	4,5 unsaturated uronic acid residue-N-acetyl galactosamine, 4-O-sulfate, ∆UA-GalNAc4S
DQC	Dilution Quality Control
HQC	High Quality Control
LQC	Low Quality Control
MQC	Medium Quality Control