MPS II	Mucopolysaccharidosis type II
NBS	Newborn screening
ICV	Intracerebroventricular
ERT	Enzyme replacement therapy
ICV-ERT	Intracerebroventricular enzyme replacement therapy
CBT	Cord blood transplantation
HS	Heparan sulfate
LSDs	Lysosomal storage disorder
I2S	Iduronate-2-sulfatase
GAGs	Glycosaminoglycans
CNS	Central nervous system
HSCT	Hematopoietic stem cell transplantation
BBB	Blood–brain barrier
4-MU	4-methylumbelliferone
MS/MS	Tandem mass spectrometry
GVHD	Graft-versus-host disease
CSF	Cerebrospinal fluid
DA	Developmental age
DQ	Developmental quotient
KSPD	Kyoto Scale of Psychological Development
SOS	Sinusoidal obstruction syndrome
IEM	Inborn errors of metabolism