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Table 2 Comparison of clinical signs, symptoms, and laboratory studies of the three siblings at baseline and after 30 months of ERT

From: Diagnostic journey and impact of enzyme replacement therapy for mucopolysaccharidosis IVA: a sibling control study

 

Patient 1

Patient 2

Patient 3

Before ERT

After ERT

Before ERT

After ERT

Before ERT

After ERT

6MWD,a m

50d

300

265

425

175f

290e

Height, cm (percentileb)

161.4 (25)

165.3 (7)

137.5 (44)

153.1 (43)

97.0 (60)

117.2 (74)

Weight, kg (percentileb)

50.8 (39)

65.3 (51)

27.9 (21)

37.1 (20)

16.6 (87)

27.3 (98)

BMI, kg/cm2 (percentileb)

19.5 (48)

23.9 (78)

14.8 (11)

15.8 (11)

17.6 (91)

19.9 (99)

Joint ROM, a degrees

 Hip abduction

R: 10

R: 20e

R: 20

R: 55

L: 15

L: 20e

L: 20

L: 55

 Hip internal rotation

R: 10

R: 10e

R: 30

R: 40e

R: 60

L: 5

L: 15e

L: 30

L: 10e

L: 60

 Knee extension

R: − 35

R: − 20

R: 0

R: 0

L: − 55

L: − 30

L: − 15

L: 0

 Ankle dorsiflexion with knee flexed

R: 8

R: 15e

L: 10

L: 15e

 Ankle dorsiflexion with knee extended

R: 0

R: 8

R: 10

R: 10

R: 15

L: 5

L: 5

L: 10

L: 10

L: 15

 Popliteal angle

R: 15

R: 25

R: 30

R: 0

L: 15

L: 35

L: 30

L: 0

Cardiac functionc

No significant findings

No significant findings

No significant changes

No significant findings

Respiratory function

 FVC,c %

150

157

71

85

 FEV1,c %

121

121

71

78

 FEV1/FVCc

71

79

101

81

 FEF25–75,c %

76

70

41

46

 Polysomnography

Snoring, no evidence of significant OSA

No evidence of OSA or restrictive lung disease

Normal breathing

No evidence of OSA or restrictive lung disease

Snoring, no evidence of substantial OSA

Ophthalmology

Mild corneal haze

Mild corneal haze

Mild corneal haze

Mild corneal haze

Subtle corneal haze

Diffuse fine corneal haze

Urinary GAGs

 Chondroitin sulfate, g/mol creatinine

7.77

2.87e

9.61

8.01e

21.2

14.19e

 Keratan sulfate, μg/mol creatinine

5.35

2.97e

7.21

6.33e

16.6

9.95e

  1. 6MWD 6-min walk distance, BMI body mass index, CDC US Centers for Disease Control and Prevention, ERT enzyme replacement therapy, FEF25–75 forced expiratory flow between 25 and75% of FVC, FEV1 forced expiratory volume in 1 s, FVC forced vital capacity, GAG glycosaminoglycan, OSA obstructive sleep apnea, ROM range of motion
  2. aInitial joint ROM and 6MWD evaluations were conducted after initiation of treatment (Patients 1 and 2, 5 months; Patient 3, 3 months)
  3. bCDC Clinical Growth Charts for 2–20 years of age
  4. cEvaluation after 20 months of ERT
  5. dAmbulation with bilateral forearm crutches in 59 s
  6. eEvaluation after 30 months of ERT
  7. fDistance walked in 2.75 min due to refusal to continue