Table 1 Phenotypic features of myoglobinopathy

Inheritance pattern

AD

AD

AD

AD

unknown

unknown

Myoglobin mutation

His98Tyr

His98Tyr

His98Tyr

His98Tyr

His98Tyr

His98Tyr

Country of origin

Spain

Spain

Sweden

France

France

Netherlands

No. of patients

2

1

6

3

1

1

Mean age of onset (range)

37.5 (36–39)

38

44.5 (39–49)

46 (44–48)

40

33

Gender (female/male)

0/2

1/0

2/4

2/1

0/1

0/1

Initial symptoms

Proximal LL and axial weakness (2/2)

Proximal LL and axial weakness (1/1)

Distal hand weakness (2/6)

Proximal LL and axial weakness (6/6)

Proximal LL and axial weakness (3/3)

Proximal LL weakness (1/1)

Proximal LL and axial weakness (1/1)

 Distribution of weakness

Proximal and axial > distal 4 EE

Proximal and axial > distal 4 EE

Proximal and axial > distal 4 EE

Proximal and distal 4 EE > axial

Proximal and axial > distal 4 EE

Proximal and axial > distal legs

 Involvement of hand muscles

2/2

1/1

6/6

2/2**

1/1

0/1

 Facial weakness

0/2

0/1

0/6

0/2

0/1

0/1

 Muscle atrophy

2/2

1/1

6/6

2/2

0/1

1/1

 Dysphagia

2/2

0/1

2/4

0/2

1/1

0/1

 Respiratory insufficiency

2/2

1/1

2/6

1/2

1/1

1/1

 Cardiac involvement*

2/2

1/1

2/6

0/2

1/1

0/1

 Mean age at wheelchair dependency

54

65

56 (4/6 patients wheelchair dependent, 2/6 ambulant)

66 (1/3 patients wheelchair dependent, 2/3 ambulant)

56

47

 Mean age at death (range)

60.5 (54–67)

–

64 (58–71)

72

–

–

 CK fold elevation above normal levels

1.5–2

2

1.5–4

2.3–3.7

4

3.5–7

 EMG

Myogenic with spontaneous activity at rest

Myogenic with spontaneous activity at rest

Myogenic with spontaneous activity at rest

Myogenic with spontaneous activity at rest

Myogenic with spontaneous activity at rest

Myogenic with spontaneous activity at rest