Table 1.

Characteristics of patients.

Variant	MLD01	MLD02	MLD03
Demographics
Ethnicity	Chinese	Chinese	Chinese
Sex	Female	Female	Female
Age at onsets, years	14.0	5.5	4.0
Age at gene therapy, years	18.1	6.8	4.5
Clinical features
Clinical subtype	Juvenile	Juvenile	Juvenile
ARSA mutation	c.251G > A; c.439delA	c.257G > A; c.827C > T	c.925G > A; c.1237G > A
PSAP mutation	None	None	None
Patient conditioning
Busulfan
Dose, mg/kg	0.8	1.2	1.1
Total dosage, mg	768.0	432.0	281.6
Duration of neutropenia
Severea, days	3.0	5.0	5.0
Absoluteb, days	3.0	2.0	2.0
HSCGT dose, ×106 cells/kg	7.1	10.0	7.8
Duration of follow-up, years	9.6	6.9	4.5
Long-term outcomes
ARSA activity, nmol/17 h/mg
Baseline	4.23	3.68	15.70
Last follow-up	85.18	84.62	171.91
FIM score
Baseline, motor points	36.0	85.0	91.0
Last follow-up, motor points	89.0	55.0	91.0
Baseline, cognition points	6.0	15.0	35.0
Last follow-up, cognition points	24.0	17.0	35.0
Baseline, total score points (level)	42.0 (maximal assistance)	77.0 (moderate assistance)	126 (complete independence)
Last follow-up, total score points (level)	113.0 (modified independence)	78.0 (moderate assistance)	126 (complete independence)
GMFC-MLD
Baseline, points (level)	4	0	0
Last follow-up, points (level)	0	1	0
MRI lesion score
Baseline, points (level)	18.0 (moderate)	21.0 (severe)	1.0 (mild)
Last follow-up, points(level)	16.0 (moderate)	14.0 (moderate)	9.0 (moderate)
Laboratory tests
VCN of CD34+
Baseline, copy/cell	0.0	0.0	0.0
After transduction, copy/cell	0.21	0.79	0.32
VCN of PBMC
Baseline, copy/cell	0.0	0.0	0.0
Last follow-up, copy/cell	0.16	0.08	0.26

^aSevere neutropenia refers to an ANC < 500 × 10⁶ neutrophils/L.

^bAbsolute neutropenia was considered an ANC of 0 neutrophils/L.

Abbreviations: ND, not done; PT, post treatment.