Echocardiography: a requisite friend of the cardiac geneticist.

790 In this issue of the Journal of the American Society of Echocardiography, Mottram et al. illustrate the role of echocardiography in the early detection of the expression of a mutation in the protein frataxin known to cause Friedreich’s ataxia. It triggers this editorial tribute to echocardiography and the role cardiac echocardiographers have played in our pursuit of genetic cardiac disorders. Echocardiography is well recognized for its noninvasive application. It does not require isotopes, so there is no risk of radiation. It does not require magnetic resonance, so it can be used conveniently and in a patient-friendly manner, even with an in-dwelling device such as a pacemaker. Echocardiography is also portable. The portability lends many advantages, such as for very ill patients who cannot be moved and for screening in the clinic or in the field. Second, it provides both anatomy and function. It also provides comprehensive assessment of all four chambers, the four valves, and the great vessels taking blood to and from the heart. Echocardiography, with its modifications such as Doppler and two-dimensional imaging, has become the standard to detect the phenotypes of inherited cardiac diseases. The inherited cardiac diseases are usually divided into structural and nonstructural groups. It is self-evident that echocardiography is the sine qua non to detect and elucidate structural cardiac disease. However, those with nonstructural disease will require echocardiography to exclude structural disease and/or to assess ventricular and atrial function. It is estimated there are 6000 rare single-gene disorders. In the past 20 years, >2000 responsible genes have been identified. More than 200 of these genes involve cardiac disease. The bulk of them relate to cardiomyopathies, including hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy, while others relate to rhythm disturbances such as long-QTsyndrome. The phenotype of cardiomyopathy has traditionally been detected by echocardiography as it still is today. It is true that arrhythmogenic right ventricular cardiomyopathy, once it is detected by echocardiography, is often further assessed using magnetic resonance imaging if available. In patients presenting with symptoms such as syncope or palpitations, echocardiography is an essential tool to exclude structural abnormalities and to assess ventricular function. The most common cause of sudden cardiac death (SCD) at <35 years of age is an inherited cardiac abnormality. The norm rather than the exception for SCD in this age group is a lack of symptoms preceding the event. HCM is claimed to be the most common cause of SCD in patients aged <35 years. However, in Italy, the most common cause of SCD is arrhythmogenic right ventricular cardiomyopathy. HCM occupies a unique position because it is considered to