False positives include other conditions with fatty infiltration of the ventricle, such as long-term excessive alcohol use and Duchenne or Becker muscular dystrophy. False negatives are common, however, because the disease progresses typically from the epicardium to the endocardium (with the biopsy sample coming from the endocardium), and the segmental nature of the disease. Also, due to the paper-thin right ventricular free wall that is common in this disease process, most biopsy samples are taken from the ventricular septum, which is commonly not involved in the disease process. A biopsy sample that is consistent with ACM would have > 3% fat, >40% fibrous tissue, and <45% myocytes. A post mortem histological demonstration of full thickness substitution of the RV myocardium by fatty or fibro-fatty tissue is consistent with ACM. Genetic testing
ACM is an autosomal dominant trait with reduced penetrance. Approximately 40–50% of ACM patients have a mutation identified in one of several genes encoding components of the desmosome, which can help confirm a diagnosis of ACM. Since ACM is an autosomal dominant trait, children of an ACM patient have a 50% chance of inheriting the disease-causing mutation. Whenever a mutation is identified by genetic testing, family-specific genetic testing can be used to differentiate between relatives who are at-risk for the disease and those who are not. ACM genetic testing is clinically available. Diagnostic criteria
There is no pathognomonic feature of ACM. The diagnosis of ACM is based on a combination of major and minor criteria.
Based on these findings and other evidence, it is thought that in most patients, additional factors such as other genes, athletic lifestyle, exposure to certain viruses, etc. may be required for a patient to eventually develop signs and symptoms of ACM. It accounts for up to 17% of all sudden cardiac deaths in the young. In Italy, the prevalence is 40/10,000, making it the most common cause of sudden cardiac death in the young population. Society and culture
Notable cases
Columbus Crew midfielder Kirk Urso collapsed out with friends on August 5, 2012, and was pronounced dead an hour later. An autopsy later revealed the disease to be the likely culprit. Sevilla FC and Spanish international left wing-back Antonio Puerta died from the condition, at the age of 22, on 28 August 2007, three days after suffering several cardiac arrests, while disputing a La Liga game against Getafe CF. Englishman Matt Gadsby also died from the condition after collapsing on the pitch on 9 September 2006, while playing for Hinckley United in a Conference North game against Harrogate Town. Suzanne Crough, an American child actress best known for her role on The Partridge Family, died suddenly from the condition in 2015 at age 52. James Taylor English international cricketer, retired April 2016. Krissy Taylor, an American model, died at the age of 17 on July 2, 1995, in the family home in Florida. Her official cause of death was cardiac arrhythmia and severe asthma, the latter of which she had never been diagnosed with.