Table 1 Characteristics of the study population (n=94) ^a

Gender (males)

Age at first study visit (years)

Age at onset of symptoms (years)

• < 18 years

• ≥ 18 years

Age at diagnosis (years)

Disease duration since onset of first symptoms at first study visit (years)

Time since diagnosis at first study visit (years)

• 0 to 5 years

• 5 to 10 years

• 10 to 15 years

• > 15 years

Use of walking aids

Wheelchair use

Age at start of wheelchair use (years)

Use of mechanical ventilation ^b

Age at start of mechanical ventilation (years)

First symptoms noted ^c

Skeletal muscle weakness

• Difficulty running

• Difficulty performing sports

• Difficulty climbing stairs

• Difficulty walking

• Difficulty rising from an armchair

• Difficulty rising from a lying position

Fatigue

Muscle soreness / cramps

Respiratory failure

Clinical features

Ptosis

Bulbar muscle weakness ^d

Scapular winging ^d

Scoliosis

Increased lumbar lordosis

Prominent muscle atrophy

• Shoulder girdle / upper arms

• Trunk muscles

• Pelvic girdle / Upper leg (Figure1a)

Laboratory parameters

CK (U/l)

• Males

• Females

α-glucosidase activity in leukocytes (nmol glucose/h/mg protein) ^e

α-glucosidase activity in fibroblasts (nmol 4-MU/h/mg protein) ^f

Genotype

• c.-32-13T>G / very severe or potentially less severe pathogenic mutation

• c.671G>A / c.525del

• unknown