Prognosis
A significant proportion of those with CPVT will experience a life-threatening abnormal heart rhythm, with estimates of this risk ranging from 13 to 20% over the course of 7–8 years. Life-threatening arrhythmias are more likely to occur if CPVT has been diagnosed in childhood, if a person with CPVT does not take beta blockers, and if arrhythmias occur on exercise testing despite taking beta blockers.During treatment with nadolol, the preferred beta blocker for the treatment of CPVT, event rates have been estimated to be 0.8% per year. In patients treated with beta blockers, life-threatening arrhythmias are more likely if a person had already survived a cardiac arrest, had a syncope, or are carriers of disease-causing mutations affecting the highly conserved terminal portion of RYR2 gene, called the C-terminal domain (amino acids 4889–4969). Epidemiology
CPVT is estimated to affect 1 in 10,000 people. Symptoms from CPVT are typically first seen in the first or second decade of life, and more than 60% of affected individuals experience their first episode of syncope or cardiac arrest by age 20. Syncope during exercise or strong emotion should be considered a red flag, as it is a characteristic of the disease. Lastly, a small number of patients may present later in life, and genetic testing in these patients frequently fails to identify a causative gene. History
In 1960, Norwegian cardiologist Knut Berg published a report on three sisters who had blackouts during exercise or emotional stress in what is now recognised as the first description of CPVT.
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Type III – obesity and pseudoacanthosis nigricans
In young persons, acanthosis nigricans is a visible marker which strongly suggests insulin resistance. Higher than normal insulin levels in the blood stream cause the growth of darkened skin over certain areas of the body. No skin treatment will get rid of AN. Acanthosis nigricans may lighten up and possibly go away by treating the root cause, insulin resistance, but it can take months or years to do so. Insulin resistance syndromes may be divided into type A (HAIR-AN) and type B syndromes. : 978 The majority of cases of acanthosis nigricans are associated with obesity and otherwise idiopathic. This is likely because of insulin resistance and more likely to occur in darker-skinned persons. : 968  This can also be referred to as pseudoacanthosis nigricans. : 86  In some cases, AN attributable to obesity and insulin resistance will occur on ones face. Most typically it will be present as a horizontal band on the forehead, but may also appear as perioral hyperpigmentation, periorbital hyperpigmentation, or generalized facial skin darkening. Type IV – drug-related
Acanthosis nigricans has been linked to the use of nicotinic acid, glucocorticoid use, combined oral contraceptive pills, and growth hormone therapy. : 86

Type V – malignancy
Malignant acanthosis nigricans: 86  refers to acanthosis nigricans occurring as a paraneoplastic syndrome associated with a cancer. Malignant acanthosis nigricans is most commonly associated with gastrointestinal adenocarcinomas, as well as genitourinary cancers such as those of the prostate, breast, and ovary. Other cancers, such as those of the lung, stomach, and lymphoma, are occasionally associated with acanthosis nigricans.