Table 1 Clinical characteristics of cases

Age (y)

46

34

52

Sex

M

M

F

Duration of symptoms prior to first evaluation (mo)

5

12

36

Muscle symptoms

Limb weakness

UE > LE

LE > UE

LE > UE

Neck flexor

–

–

–

Muscle atrophy

–

–

–

Max CK/(U·L^− 1) (reference range 25–195 U/L)

8528

806

2043

Anti-mitochondrial antibody

+

+

+

Myositis-specific antibodies

Associated antibodies*

ANA 1:320

Ro-52

ANA 1:1000

Ro-52

Irritable myopathy on EMG

+

+

+

Serum creatinine/(µmol·L^− 1) (reference range 44–133 µmol/L)

60.11

44.46

42.00

Proteinuria

1.83 g/24 h

0.30 g/24 h

+++

Complements

C3/(g·L^− 1) (reference range 0.6–1.5 g/L)

Not tested

1.180

0.721

C4/(g·L^− 1) (reference range 0.12–0.36 g/L)

Not tested

0.064

0.168

Autoimmune diseases

PBC

+

+

+

AIH

–

–

+

Hashimoto thyroiditis

–

–

+

Cardiac

Cardiomyopathy

–

+

+

Arrhythmia

Heart block

+

–

+

PVC

–

+

+

AF

–

–

+

ILD

–

–

+

Respiratory failure, type 2

–

+

+

Arthritis

–

–

–

Skin rash

–

–

–

Treatments received

Pred

Pred, MTX, RTX

Pred, MTX, CTX