Table 2.
Demographic and Clinical Features and Outcomes of Juvenile Myositis Patients with Anti-HMGCR Autoantibodies Compared to those with other Myositis Autoantibodies.
| Feature | Anti-HMGCR (n=5) | Anti-SRP (n=8) | Anti-Synthetase (n=16) | Anti-p155/140 (n=142) | Anti-MJ (n=111) | MSA and MAA negative (n=62) | |
|---|---|---|---|---|---|---|---|
|
| |||||||
| Median [IQR] | Median [IQR] | Median [IQR] | Median [IQR] | Median [IQR] | Median [IQR] | ||
| Age at Diagnosis (yr.) | 8.1 [7.1–12.0] |
14.9 [10.7–16.0] |
14.0 [8.2–16.6] |
7.2 [4.4–11.0] |
6.3 [4.5–10.3] |
8.4 [5.4–11.5] |
|
| Delay in Diagnosis (mo.) | 3.3 [2.8–4.6] |
1.9 [1.1–5.4] |
6.9 [1.5–13.0] |
5.0 [2.0–10.0] |
3.0 [1.0–7.0] |
4.0 [2.0–12.0] |
|
|
| |||||||
| N (%) | N (%) | N (%) | N (%) | N (%) | N (%) | ||
|
| |||||||
| Gender | Female | 3 (60.0) | 5 (62.5) | 13 (81.3) | 115 (81.0) | 76 (68.5) | 37 (59.7) |
| Race | Caucasian | 3 (60.0) | 1 (14.3) | 9 (56.3) | 115 (81.0) | 79 (71.2) | 41 (66.1) |
| African American | 1 (20.0) | 6 (85.7) | 5 (31.3) | 6 (4.2) | 17 (15.3) | 7 (11.3) | |
| Other | 1 (20.0) | 0 (0) | 2 (12.5) | 21 (14.8) | 15 (13.5) | 14 (22.6) | |
| Disease Onset Speed | Insidious (>6 mo.) | 0 (0) | 2 (28.6) | 10 (62.5) | 60 (42.6) | 33 (30.0) | 24 (40.7) |
| Slow (3–6 mo.) | 2 (40.0) | 1 (14.3) | 2 (12.5) | 32 (22.7) | 27 (24.6) | 21 (35.6) | |
| Subacute (1–3 mo.) | 3 (60.0) | 4 (57.1) | 0 (0) | 33 (23.4) | 31 (28.2) | 10 (17.0) | |
| Onset Severity | Mild/Moderate | 0 (0) | 0 (0) | 8 (50.0) | 114 (80.3) | 73 (66.4) | 42 (71.2) |
| Severe/Very Severe | 5 (100) | 7 (100) | 8 (50.0) | 28 (19.7) | 37 (33.6) | 18 (28.8) | |
| Disease Course | Chronic | 4 (80.0) | 6 (75.0) | 10 (62.5) | 76 (53.5) | 41 (36.9) | 22 (35.5) |
| Polycyclic | 1 (20.0) | 0 (0) | 2 (12.5) | 22 (15.5) | 26 (23.4) | 14 (22.6) | |
| Monocyclic | 0 (0) | 0 (0) | 2 (12.5) | 14 (9.9) | 26 (23.4) | 16 (25.8) | |
| Undefined | 0 (0) | 2 (25.0) | 2 (12.5) | 30 (21.1) | 18 (16.2) | 10 (16.1) | |
| Outcomes | Ever hospitalized | 5 (100) | 8 (100) | 11 (68.8) | 66 (48.9) | 68 (64.2) | 28 (50.0) |
| Calcinosis | 1 (20.0) | 0 (0) | 1 (6.3) | 41 (28.9) | 40 (36.0) | 24 (38.7) | |
| Wheelchair use | 2 (40.0) | 6 (75.0) | 3 (20.0) | 16 (11.5) | 27 (25.2) | 4 (7.0) | |
| Devices for mobility | 0 (0) | 5 (71.4) | 2 (13.3) | 12 (8.6) | 12 (11.2) | 1 (1.8) | |
| Mortality | 0 (0) | 0 (0) | 2 (12.5) | 3 (2.1) | 2 (1.8) | 3 (4.8) | |
Abbreviations: hydroxy-3-methylglutaryl-coenzyme A reductase; SRP, signal recognition particle; ARS, anti-synthetase; p155/140, transforming inhibitory factor-1, TIF-1; MSA, myositis-specific autoantibodies; MAA, myositis-associated autoantibodies; Ab, autoantibodies;