Table 1.
Results of clinical, radiological and laboratory examinations
| Patient 1 | Patient 2 | Patient 3 | |
|---|---|---|---|
| Gender | Male | Male | Male |
| Descent | New Zealand/British | British | British |
| Age, years | 49 | 52 | 34 |
| Age of onset, years | 34 | 46/50 | 23 |
| Initial symptoms | Shortness of breath, chest pain on exertion, lethargy and palpitations | CVA/Chest pain, sweatiness and palpitations | Shortness of breath and chest pain |
| ICD | Age 45 years | Age 49 years | Age 31 years |
| Cardiac MRI (with gadolinium) | Severely impaired left ventricular function with severe dilatation. Thinned out myocardium in the posterolateral wall showing almost full thickness scarring. Diffusely patchy scarring mostly in the epicardial and mid-myocardial regions. | Severely dilated LV with a large area of thinning and akinesis affecting the entire lateral wall from base to apex (anterolateral, anterior and inferolateral walls). Other regions were hypertrophied with preserved systolic function. Extensive late gadolinium enhancement in the entire thinned region. | Very extensive (>50 %) late gadolinium enhancement in a non-ischaemic pattern. Moderate LV impairment. Maximum LV wall thickness of 23 mm. |
| ECG (before ICD insertion) | Sinus rhythm. Widespread T wave inversion. QRS duration 120 ms | Sinus rhythm with poor lateral R wave progression. QRS duration 126 ms. QTc normal. | T wave inversion in leads I, II, III, AVF and V6 with ST elevation in leads V3-V6. QRS duration 102 ms. QTc normal. |
| Echocardiogram | Age 48 years | Age 50 years | Age 32 years |
| Left ventricular end-diastolic volume (ml) | 281 | 277 | 151 |
| Septal wall thickness (cm) | 1,4 | 1,6 | 1,6 |
| Posterior wall thickness (cm) | 0,9 | 1,0 | 1,4 |
| Ejection fraction (%) | 25–30 | 30–35 | 59 |
| Coronary angiogram | Normal | Normal | Normal |
| Heart transplantation | Age 48 years | Age 52 years | No |
| Endomyocardial biopsy Light microscopy |
PAS-positive inclusions partial removal by diastase | PAS-positive inclusions partial removal by diastase | PAS-positive inclusions |
| Electron microscopy | Normal glycogen and filamentous or amorphous material | Not performed | Storage of non-lysosomal glycogen |
| Muscle biopsy | Variability of fibre size and scattered fibres with accumulation of PAS-positive inclusions | Not performed | Not performed |
| Skeletal muscle strength | Normal | Normal | Normal |
| GYG1 mutation | Homozygous c.304G > C, p.(Asp102His) |
Homozygous c.304G > C, p.(Asp102His) |
Homozygous c.304G > C, p.(Asp102His) |
ICD Implantable cardioverter-defibrillator, CVA Cerebral vascular accident, MRI Magnetic resonance imaging, LV Left ventricle, ECG Electrocardiography, PAS Periodic acid-Schiff