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Laminopathy Diseases: At the present time, genetic mutations in the lamin A/C gene (LMNA) have been linked to over 10 different diseases, including: Dilated Cardiomyopathy, Arrhythmogenic Right Ventricular Cardiomyopathy, Emery Dreifuss Muscular Dystrophy Type 3, Limb-Girdle Muscular Dystrophy type 1B, Charcot-Marie-Tooth-Disease Type 2B, Mancibuloacral Dysplasia, Familial Partial Lipodystrophy, Hutchinson-Gilford Progeria, Heart-hand syndrome (Slovenian type), Lethal Tight Skin Contracture syndrome, Benign Scapuloperoneal Muscular Dystrophy with Cardiomyopathy, and Dilated Cardiomyopathy-Hypergonadotrophic Hypogonadism syndrome.
Importantly, most patients with LMNA mutations will have ONLY ONE of the above conditions.
This website currently focuses predominantly on LMNA mutations leading to Dilated Cardiomyopathy. Further information on the other diseases caused by LMNA mutations can be found on at the Genetics Home Reference.
Dilated Cardiomyopathy due to LMNA mutations:
Patients with Dilated Cardiomyopathy LMNA genetic mutations can develop problems with the size and function of their heart. Over time, the heart size increases and can contain more blood than is normal. This 'enlargement' of the heart is often described as 'dilated'. Along with an enlarged heart, the function of the heart declines and the heart is no longer able to pump enough blood to meet the demands of the body. The 'decline' in heart function is often described as a 'cardiomyopathy', which roughly translates to a problem or disease of the heart muscle.
The result of dilated cardiomyopathy is that the enlarged heart is unable to pump enough blood and oxygen for the body's need. Doctors often refer to this problem as 'heart failure'. The American Heart Association provides high quality information about heart failure. Symptoms may include: fatigue, feeling short of breath (especially when lying down flat or with exercise), swelling of the legs due to fluid accumulation (called 'edema'), a chronic cough or wheezing, and other symptoms.
Heart failure is common in adults over the age of 60 years. Genetic forms of heart failure, including dilated cardiomyopathy due to LMNA mutations, can occur much earlier in life and may start affecting persons between the age of 20-40 years. Sometimes it can occur earlier in teenagers, or even later in life where it mimics more typical heart failure. Most persons need to be evaluated by a doctor before a diagnosis of heart failure can be made. If the person is younger than the typical age for heart failure or there is no clear explanation for the heart failure, genetic causes (including LMNA mutations) might be considered.
Dilated Cardiomyopathy: Other Findings
In addition to an enlarged heart that has reduced heart function, persons with LMNA mutations may also have problems with the electrical activity in their heart. This may cause arrhythmias that patients may notices as palpitations (racing heart), lightheadedness, or even episodes of passing out. An doctor may request an electrocardiogram (also called an 'ECG' or 'EKG') to measure the electrical activity of the heart. In persons with LMNA mutations, the electrocardiogram may show arrhythmias or heart block. Muscle disease is also quite common and may be experienced as muscle weakness by the affected person or noted through laboratory testing.