Table 2.
Summary of studies reporting treatment and cognitive outcomes for MPS IA
| Author (year) | MPS I (N) | Treatment | Age at treatment | Age at treatment for group comparisons | Follow-up duration | Baseline cognitive score | Posttreatment cognitive scores or key study findings |
|---|---|---|---|---|---|---|---|
| Wang et al. (2009)20 | 2 (siblings) | ERT | Pt 1: 51 months, n = 1; Pt 2: 6 months, n = 1 | 48-month follow-up | Both patients: “cognitively
normal.” Pt 1: severe white matter abnormalities. Pt 2: few to mild white matter abnormalities |
Cognitive skills “normal” (scores not reported). Severe white matter abnormalities observed at baseline in Pt 1 (older sibling) diminished with treatment. Few, mild white matter abnormalities in Pt 2 (younger sibling) at baseline that improved further at follow-up. | |
| Valayannopoulos et al. (2010)20a | 3 | ERT | Pt 1: 120 months, n = 1; Pt 2: 72 months, n = 1; Pt 3: 54 months, n = 1 | Pt 1: 54 months; Pt 2: 48 months; Pt 3: 42 months |
Pt 1: IQ in normal range (score not
reported); Pt 2: low average; Pt 3: low average |
Pt 1: IQ score remained stable across follow-up (normal range, scores not reported). Pt 2: IQ score increased by 13 points (low average to average). Pt 3: IQ score increased by 29 points (low average to average) | |
| Shapiro et al. (2012)21 | A: 7 MPSI-A; B: 7 MPSI-H | A: ERT; B: HCT | A: not reported; B: 5–20 months (M 14) | A: At least 3 months after ERT; B: at least 5 years after HCT | Mean cognitive scores not statistically different between children with MPSI-A (M 85) and MPSI-H (M 78). Children with MPSI-A scored significantly better than those with MPSI-H on a measure of attention. | ||
| Shapiro et al. (2015)8b | 25 MPSI-A | ERT | A: Age at visit <72 months: M age at ERT
29 months, post- ERT assessment M 19 months, n
= 4. B: Age at visit >72 months: M age at ERT 108 months, post- ERT assessment M 76 months, n = 21 |
NA (cross-sectional) | Significant predictor of higher IQ scores: nonsevere genotype (+20 IQ pts) | ||
| Al-Sannaa et al. (2015)23 | 20 (9 sibships) | ERT | A: Older sibs m 168 months,
n = 10; B: younger sibs <48 months, n = 10; group B1: 1st ERT <15 months; group B2: 1st ERT 24 to 48 monthsc |
Symptoms were absent or mild for younger siblings in Group B1; symptom frequency was greater for younger siblings in group B2; nevertheless, younger siblings in group B2 had fewer motor and cognitive deficits than older siblings |
ERT, enzyme replacement therapy; HCT, hematopoietic cell transplantation; IQ, intelligence quotient; M, mean; m, median; MPS I, mucopolysaccharidosis type 1.
Valayannopoulos et al.20 did not report IQ scores numerically. For patients 2 and 3, IQ scores represented in bar graph form only.
Shapiro et al.8 reported on a cross-sectional sample with patients affected by both MPSI-H (N = 60) and MPSI-A (N = 29). Of the 29 MPSI-A patients, only those evaluated as children (<25 years of age, n = 25) are reported in the present study. Comparison groups based on phenotype and age at visit, further categorized as 2 to <6 years and ≥6 years to 25 years, based on use of different cognitive tests.
As reported by Al-Sannaa et al.23. Excludes one younger sibling who started ERT at age 8.6 years.