Dilated cardiomyopathy is a progressive disease of heart muscle, characterized by ventricular chamber enlargement and contractile dysfunction with normal left ventricular (LV) wall thickness. The right ventricle may also be dilated and dysfunctional. Dilated cardiomyopathy has a prevalence of one case out of 2500 individuals with an incidence of 7/100,000/year, and it is the third most common cause of heart failure and the most frequent reason for heart transplantation. DCM is an idiopathic disease and sometimes appear sporadically. In many cases, the disease is inherited and is termed familial DCM (FDC). FDC may account for 20-48% of DCM. Different forms have been identified based on patterns of transmission and characteristics of the phenotype, these include: autosomal dominant FDC without extracardiac manifestations; autosomal recessive FDC; FDC with X-linked transmission; autosomal dominant FDC with subclinical skeletal muscle involvement; autosomal dominant FDC with conduction defects; autosomal dominant left ventricular non-compaction; unclassifiable FDC with retinitis pigmentosa and hearing loss. Diagnosis of DCM is based on medical history, physical exam, blood tests, electrocardiogram (ECG or EKG), chest X-ray, echocardiogram, exercise stress test, cardiac catheterization, CT scan, and MRI. Genetic testing may also be available to identify abnormal genes. There are no therapies that can cure DCM; however, some therapeutic interventions treat symptoms, whereas others treat factors that affect survival. In some severe cases, heart transplantation is needed.
Seliem et al. (2000) described 55 cases of dilated cardiomyopathy in patients less than 10 year old of age from 41 Saudi families from the Eastern Province. Among these families, one family had four affected offspring, three families each had four affected offspring, one family had two affected offspring, and 36 families had a single affected offspring. There were 21 affected males and 34 affected females. Age at presentation was less than 30 months (95%; range, 1 to 100 months); 26 patients were less than 12 months of age, 49 patients were less than 24 months, and 52 patients were less than 30 months. In 19 families, parents were first cousins, while the other 22 families were not consanguineous. All affected patients presented with congestive heart failure and respiratory distress. Twenty five patients died, the left ventricular shortening fraction (LVSF%) returned normal in 15 patients, and in 15 the LVSF% improved from the initial study. Complex segregation analysis of the family data, using the mixed model of inheritance, showed that a model of recessive inheritance was probable.