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Table 2 Main phenotype data in all Spanish McArdle patients (n = 333)

From: Genotypic and phenotypic features of all Spanish patients with McArdle disease: a 2016 update

  N with data Result (men + women) Main change with regards to previous data (n = 239 patients) [1]
Gender   55% male
Age, years
(mean ± SD, range)
333 48 ± 19 (12, 99)a
BMI, kg/m2
(mean ± SD, range)
132 24.7 ± 4.8 (16, 43)
Familial consaguinity (%) 188 17%
Symptomatic father (%)a 201 3%
Symptomatic mother (%)a 201 6%
Symptoms’ onset (%) 235   
1st decade   66%
2nd decade   20%
3rd decade   5%
≥4th decade   9%
Genetic diagnosis (%) 275   
1st decade   5%
2nd decade   23%
3rd decade   23%
≥4th decade   49%
Exercise intolerance (%) 272 99.6%
Second wind, self-reported (%) 164 91.5%
Second wind, laboratory- determined (%) 119 99.2%
Fixed muscle weakness (%) 240 21%
Recurrent episodes of myoglobinuria (%) 240 51%
Disease severity (%)b 240   
Class 0   8%
Class 1   41%
Class 2   30%
Class 3   21%
Disease progression (%) 151   
Improvement   34% ↑↑
Worsening   28%
Constant   35% ↓↓
Acute renal failure (%) 173 6%
Chronic renal failure (%) 171 1%
Comorbidities (%)
Diabetesc 140 9%
CAD 136 9%
Hypertension 135 11%
Cancer 134 1%
Obesity 127 10%
COPD 131 1%
Serum CK (%) >200 U/L, >1000 U/L 179 98%, 68% ↔, ↓
Biopsy diagnosis (%) 205 100%
Physical activity data (% active) 120 50% ↑↑
VO2peak, mLO2/kg/min (mean ± SD, range) 120 19.9 ± 6.6 (5.9, 41.5)
  1. Data on 3 patients (all males) who died recently (all after the 6th decade of life, due to cardiovascular disease) are included
  2. Symbols: a ‘symptomatic’ refers to having the main symptomatic features of McArdle disease (i.e., exercise intolerance with or without myoglobinuria or self-reported second wind)
  3. bdisease severity class following the classification originally reported by Martinuzzi et al. [2]: 0 = asymptomatic or virtually asymptomatic (mild exercise intolerance, but no functional limitation in any daily life activity); 1 = exercise intolerance, contractures, myalgia, and limitation of acute strenuous exercise, and occasionally in daily life activities; no record of myoglobinuria, no muscle wasting or weakness; 2 = same as 1, plus recurrent exertional myoglobinuria, moderate restriction in exercise, and limitation in daily life activities; 3 = same as 2, plus fixed muscle weakness, with or without wasting and severe limitations on exercise and most daily life activities
  4. cdiabetes diagnosed based on a glucose tolerance test. Abbreviations: BMI, body mass index; CAD, coronary artery disease; COPD, chronic obstructive pulmonary disease; VO2peak, peak oxygen uptake