The group of familial cardiomyopathies is one of the primary cardiomyopathies (Brieler 2017).
Familial cardiomyopathies include:
- 1. hypertrophic cardiomyopathy (HCM).
HCM represents the most common familial cardiomyopathy with an incidence of 1: 500 (Stiefelhagen 2020). It is familial in approximately 50% and is inherited in an autosomal dominant manner (Kaltenbach 2013). It is a disease of the sarcomere, resulting in concentric, asymmetric, and apical myocardial hypertrophy (Sieverding 2020).
Deaths have been described in sports starting at 10 years of age (Moog 2014).
- 2. arrhythmogenic (right) ventricular cardiomyopathy (A[R]VC):
A(R)VC was originally described as a disease of the right ventricle. However, it has since been shown that one or both ventricles can be affected (Kasper 2015).
The disease is rather rare with an incidence of 1: 5,000 (Stiefelhagen 2020). A(R)VC shows a familial clustering in about 30% (Kaltenbach 2013).
The mode of inheritance is predominantly autosomal dominant with genetic heterogeneity and variable clinical expression (Greten 2010). The mutation affects cell contact proteins (Stiefelhagen 2020). This results in electroanatomical abnormalities (Sieverding 2020). Deaths in sports have also been described from the age of 10 (Moog 2014).
- 3. long QT syndrome (LQT):
An autosomal dominant inheritance is found in the more common form, also known as Romano-Ward syndrome, and an autosomal recessive inheritance in the rarer variant, Jervell and Lange-Nielsen syndrome (Greten 2010).
The disease usually occurs in late childhood or early adolescence. Girls are more frequently affected (Greten 2010).
The syndrome is blamed for drowning accidents in children (Moog 2014).
- 4. brugada syndrome:
Brugada- syndrome is a genetically heterogeneous disorder. Approximately 20 % of the patients have a defect in the ion channel (Greten 2010).
This can lead to life-threatening arrhythmias, particularly in the context of high-fever infections (Moog 2014).
- 5. dilated cardiomyopathy (DCM):
DCM is the most common form of all cardiomyopathies and is familial in 25% (Stiefelhagen 2020 / Wappler 2011). Kasper (2015) reports familial involvement at 30%, and the incidence is 1: 2,500 (Kaltenbach 2013).
There is a predominantly autosomal dominant inheritance, more rarely an autosomal recessive, X chromosomal (Kaltenbach 2013) or mitochondrial. So far, > 40 genes have been identified as carriers of the mutation (Soares 2017). Men usually develop cardiomyopathy 10 years earlier than women, albeit asymptomatically (Kasper 2015).
Approximately 30% have a mutation of DCM-associated genes (Meder 2017).
- 6. restrictive cardiomyopathy (RCM):
This is a rare disease that can occur in association with scleroderma, sarcoidosis, Fabry disease, Gaucher disease, Hurler disease, etc (Greten 2010). In this case, there is a reduced distensibility of the myocardium and mutations of troponin I (Sieverding 2020).
RCM manifests itself predominantly in conduction disorders (Meder 2017).
- 7. noncompaction cardiomyopathy (NCCM), also known as left ventricular noncompaction cardiomyopathy (LVNC):
The incidence of NCCM is 1: 1,000 and the disease is inherited in an autosomal dominant manner. NCCM shows genetic and phenotypic overlap with hypertrophic cardiomyopathy and dilated cardiomyopathy (Stiefelhagen 2020).
Approximately 5% of cardiomyopathies in children are due to NCCM. The disease leads to an increased risk of thromboembolic events and arrhythmias (Hänselmann 2020).
- 8. ion channel diseases/primary arrhythmia syndromes:
These include, for example, long Q syndrome, Brugada syndrome (Schimpf 2013).
Mostly, these are mutated sodium and potassium ion channels (Engelhardt 2022).
With regard to ion channel diseases, no other field has so many findings on direct correlations between genetic cause and clinical phenomenon. Nevertheless, due to the large number of changes in the ECG, there is still uncertainty regarding the relevance of the findings (Ziakos 2019).
The mode of inheritance is autosomal dominant in the majority of cases (Beckmann 2011).
Before the age of 40, 3 in 100,000 individuals experience sudden cardiac death. In more than half, a hereditary arrhythmia syndrome can be identified retrospectively (Schaaf 2018).
- 9. mitochondrial cardiomyopathies:
Mitochondrial diseases represent a heterogeneous group of multisystemic diseases.
In mitochondrial cardiomyopathy, there is a disruption of mitochondrial protein import into the inner mitochondrial mambrane (Wachoski- Dark 2022). This disrupts cardiac structure and/or function and manifests as hypertrophicor dilated cardiomyopathy, heart failure, arrhythmias, and left ventricular myocardial noncompaction (Meyers 2013).
The mutations affect the mtDNA and nDNA, respectively. The incidence of mitochondrial disease is 1: 10,000, and there is an inheritance pattern with autosomal dominant, recessive, and X chromosomal inheritance (Meyers 2013). This mitochondrial cardiomyopathy is one of the rare forms of cardiomyopathy (Gerok 2007).
- 10. syndromic cardiomyopathies:
The syndromic cardiomyopathies may occur in the context of the following diseases such as Fabry disease or Danon disease. There is an X- chromosomal inheritance (Meder 2017). This form of cardiomyopathy results in dilatation with defects in conduction of excitation (Meder 2017).
- 11. familial amyloid cardiomyopathy.
This is inherited in an autosomal dominant manner. In this case, there are mutations of transthyretin. The conduction system is often affected (Erdmann 2009).
Clinically, a restrictive cardiomyopathy is found due to amyloid deposits (Roskamm 2013). In this disease, monoclonal proteins are found in the urine (Caspary 2013).