Nelson Textbook of Pediatrics 22nd Edition — Nuclear envelope disorders: EMD (emerin, X-linked) and LMNA (lamin A/C, AD). Triad: early contractures (elbows, neck, Achilles), humeroperoneal weakness, life-threatening cardiac arrhythmias (atrial standstill, ventricular tachycardia). Pacemaker/ICD essential.
🌐 paeds.online — Pakistan's Pediatric Platform| Feature | X-linked (EDMD1) | Autosomal Dominant (EDMD2/3) | Autosomal Recessive (EDMD4) |
|---|---|---|---|
| Gene | EMD (emerin) | LMNA (lamin A/C) | LMNA |
| Locus | Xq28 | 1q21 | 1q21 |
| Protein | Emerin (inner nuclear membrane) | Lamin A/C | Lamin A/C |
| Sex affected | Males (females carriers may have cardiac risk) | Both sexes | Both sexes |
| Contractures | Early: elbows, neck, Achilles | Early: elbows, neck, Achilles | Early |
| Weakness pattern | Humeroperoneal | Humeroperoneal / scapulohumeroperoneal | Variable |
| Cardiac | Conduction defects, atrial standstill, VT, sudden death | Conduction defects, dilated cardiomyopathy, sudden death | Severe |
| CK level | Mild-moderate elevation | Mild-moderate | Mild-moderate |
| Emerin immunostaining | Absent | Present (normal) | Present |
Life-threatening arrhythmias: Atrial fibrillation/flutter, atrial standstill, complete heart block, ventricular tachycardia, sudden cardiac death. May occur before significant muscle weakness develops.
Management: Annual ECG/echocardiogram/Holter. Pacemaker for symptomatic bradycardia. Implantable cardioverter-defibrillator (ICD) for ventricular arrhythmias or high-risk LMNA mutations. Antithrombotic drugs if atrial arrhythmias.
Emerin testing: Can be done on blood (lymphocytes), buccal smear, or skin fibroblasts (absent in X-linked form).