Table 1.
Clinical characteristics of two patients with mucopolysaccharidosis type I.
| Patient 1 | Patient 2 | |
|---|---|---|
| Age at case report (years) | 21 | 59 |
| Gender | Male | Female |
| Age at start of ERT (years) | 14 | 51 |
| Mucopolysaccharidosis type | I Scheie | I Scheie |
| Visual acuity right eye, left eye | 20/20, 20/25 | 20/20, 20/20 |
| Refraction right, left | +2.5–4.75 × 84; +3.0–4.25 × 82 | +8.5–0.50 × 76; +7.50–1.0 × 88 |
| ERG findings | ||
| DA 0.01 amplitude right, left (94.2–202 μV) | 119, 193 | NM, NM |
| DA 0.01 latency right, left (68.5–97.5 msec) | 77.3, 92.8 | NM, NM |
| DA 10 b-wave amplitude right, left (194.2–385.7 μV) | 111, 203 | 20.8, 48.6 |
| DA 10b-wave latency right, left (31.3–55.8 msec) | 53.2, 52.7 | 67.3, 73.3 |
| DA b-/a-wave ratio (1.2–1.9) | 1.92, 1.75 | 0.79; 3.6 |
| 30 Hz flicker amplitude right, left (46.6–130.1 μV) | 42, 53.6 | 25.6, 21.1 |
| 30 Hz flicker latency right, left (25.0–29.7 msec) | 25.8, 26.6 | 32.2, 35.7 |
| Multifocal ERG findings | Reproducible P1 responses only in ring 1 in the right eye (31.7 nV/deg2; lower limit of normal 42.5) | Reproducible responses only in ring 1 in both eyes (right 25.8, left 31.2 nV/deg2; lower limit of normal 21.6) |
DA, dark-adapted; ERG, electroretinogram; ERT, enzyme replacement therapy; NM, not measurable.