MedGen

Hereditary paraganglioma-pheochromocytoma (PGL/PCC) syndromes are characterized by paragangliomas (tumors that arise from neuroendocrine tissues distributed along the paravertebral axis from the base of the skull to the pelvis) and pheochromocytomas (paragangliomas that are confined to the adrenal medulla). Sympathetic paragangliomas cause catecholamine excess; parasympathetic paragangliomas are most often nonsecretory. Extra-adrenal parasympathetic paragangliomas are located predominantly in the skull base and neck (referred to as head and neck paragangliomas [HNPGLs]) and sometimes in the upper mediastinum; approximately 95% of such tumors are nonsecretory. In contrast, extra-adrenal sympathetic paragangliomas are generally confined to the lower mediastinum, abdomen, and pelvis, and are typically secretory. Pheochromocytomas, which arise from the adrenal medulla, typically lead to catecholamine excess. Symptoms of PGL/PCCs result from either mass effects or catecholamine hypersecretion (e.g., sustained or paroxysmal elevations in blood pressure, headache, episodic profuse sweating, forceful palpitations, pallor, and apprehension or anxiety). The risk for developing metastatic disease is greater for extra-adrenal sympathetic paragangliomas than for pheochromocytomas. Additional tumors reported in individuals with hereditary PGL/PCC syndromes include gastrointestinal stromal tumors (GISTs), pulmonary chondromas, and clear cell renal cell carcinoma. [from GeneReviews]

Hereditary paraganglioma-pheochromocytoma (PGL/PCC) syndromes are characterized by paragangliomas (tumors that arise from neuroendocrine tissues distributed along the paravertebral axis from the base of the skull to the pelvis) and pheochromocytomas (paragangliomas that are confined to the adrenal medulla). Sympathetic paragangliomas cause catecholamine excess; parasympathetic paragangliomas are most often nonsecretory. Extra-adrenal parasympathetic paragangliomas are located predominantly in the skull base and neck (referred to as head and neck paragangliomas [HNPGLs]) and sometimes in the upper mediastinum; approximately 95% of such tumors are nonsecretory. In contrast, extra-adrenal sympathetic paragangliomas are generally confined to the lower mediastinum, abdomen, and pelvis, and are typically secretory. Pheochromocytomas, which arise from the adrenal medulla, typically lead to catecholamine excess. Symptoms of PGL/PCCs result from either mass effects or catecholamine hypersecretion (e.g., sustained or paroxysmal elevations in blood pressure, headache, episodic profuse sweating, forceful palpitations, pallor, and apprehension or anxiety). The risk for developing metastatic disease is greater for extra-adrenal sympathetic paragangliomas than for pheochromocytomas. Additional tumors reported in individuals with hereditary PGL/PCC syndromes include gastrointestinal stromal tumors (GISTs), pulmonary chondromas, and clear cell renal cell carcinoma. [from GeneReviews]

Multiple endocrine neoplasia type 2 (MEN2) includes the following phenotypes: MEN2A, familial medullary thyroid carcinoma (FMTC, which may be a variant of MEN2A), and MEN2B. All three phenotypes involve high risk for development of medullary carcinoma of the thyroid (MTC); MEN2A and MEN2B involve an increased risk for pheochromocytoma; MEN2A involves an increased risk for parathyroid adenoma or hyperplasia. Additional features of MEN2B include mucosal neuromas of the lips and tongue, distinctive facies with enlarged lips, ganglioneuromatosis of the gastrointestinal tract, and a marfanoid habitus. MTC typically occurs in early childhood in MEN2B, early adulthood in MEN2A, and middle age in FMTC. [from GeneReviews]

Hereditary paraganglioma-pheochromocytoma (PGL/PCC) syndromes are characterized by paragangliomas (tumors that arise from neuroendocrine tissues distributed along the paravertebral axis from the base of the skull to the pelvis) and pheochromocytomas (paragangliomas that are confined to the adrenal medulla). Sympathetic paragangliomas cause catecholamine excess; parasympathetic paragangliomas are most often nonsecretory. Extra-adrenal parasympathetic paragangliomas are located predominantly in the skull base and neck (referred to as head and neck paragangliomas [HNPGLs]) and sometimes in the upper mediastinum; approximately 95% of such tumors are nonsecretory. In contrast, extra-adrenal sympathetic paragangliomas are generally confined to the lower mediastinum, abdomen, and pelvis, and are typically secretory. Pheochromocytomas, which arise from the adrenal medulla, typically lead to catecholamine excess. Symptoms of PGL/PCCs result from either mass effects or catecholamine hypersecretion (e.g., sustained or paroxysmal elevations in blood pressure, headache, episodic profuse sweating, forceful palpitations, pallor, and apprehension or anxiety). The risk for developing metastatic disease is greater for extra-adrenal sympathetic paragangliomas than for pheochromocytomas. Additional tumors reported in individuals with hereditary PGL/PCC syndromes include gastrointestinal stromal tumors (GISTs), pulmonary chondromas, and clear cell renal cell carcinoma. [from GeneReviews]

Andersen-Tawil syndrome (ATS) is characterized by a triad of: episodic flaccid muscle weakness (i.e., periodic paralysis); ventricular arrhythmias and prolonged QT interval; and anomalies including low-set ears, widely spaced eyes, small mandible, fifth-digit clinodactyly, syndactyly, short stature, and scoliosis. Affected individuals present in the first or second decade with either cardiac symptoms (palpitations and/or syncope) or weakness that occurs spontaneously following prolonged rest or following rest after exertion. Mild permanent weakness is common. Mild learning difficulties and a distinct neurocognitive phenotype (i.e., deficits in executive function and abstract reasoning) have been described. [from GeneReviews]

Mutations in the PRKAG2 gene (602743) give rise to a moderate, essentially heart-specific, nonlysosomal glycogenosis with clinical onset typically in late adolescence or in the third decade of life, ventricular pre-excitation predisposing to supraventricular arrhythmias, mild to severe cardiac hypertrophy, enhanced risk of sudden cardiac death in midlife, and autosomal dominant inheritance with full penetrance (summary by Burwinkel et al., 2005). [from OMIM]

Any familial isolated dilated cardiomyopathy in which the cause of the disease is a mutation in the SCN5A gene. [from MONDO]

Emery-Dreifuss muscular dystrophy (EDMD) is characterized by the clinical triad of: joint contractures that begin in early childhood; slowly progressive muscle weakness and wasting initially in a humero-peroneal distribution that later extends to the scapular and pelvic girdle muscles; and cardiac involvement that may manifest as palpitations, presyncope and syncope, poor exercise tolerance, and congestive heart failure along with variable cardiac rhythm disturbances. Age of onset, severity, and progression of muscle and cardiac involvement demonstrate both inter- and intrafamilial variability. Clinical variability ranges from early onset with severe presentation in childhood to late onset with slow progression in adulthood. In general, joint contractures appear during the first two decades, followed by muscle weakness and wasting. Cardiac involvement usually occurs after the second decade and respiratory function may be impaired in some individuals. [from GeneReviews]

An autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the ACTC1 gene, encoding actin, alpha cardiac muscle 1. [from NCI]

Any familial isolated arrhythmogenic right ventricular dysplasia in which the cause of the disease is a mutation in the DSC2 gene. [from MONDO]

SCN9A neuropathic pain syndromes (SCN9A-NPS) comprise SCN9A erythromelalgia (EM), SCN9A paroxysmal extreme pain disorder (PEPD), and SCN9A small fiber neuropathy (SFN). SCN9A-EM is characterized by recurrent episodes of bilateral intense, burning pain, and redness, warmth, and occasionally swelling. While the feet are more commonly affected than the hands, in severely affected individuals the legs, arms, face, and/or ears may be involved. SCN9A-PEPD is characterized by neonatal or infantile onset of autonomic manifestations that can include skin flushing, harlequin (patchy or asymmetric) color change, tonic non-epileptic attacks (stiffening), and syncope with bradycardia. Later manifestations are episodes of excruciating deep burning rectal, ocular, or submandibular pain accompanied by flushing (erythematous skin changes). SCN9A-SFN is characterized by adult-onset neuropathic pain in a stocking and glove distribution, often with a burning quality; autonomic manifestations such as dry eyes, mouth, orthostatic dizziness, palpitations, bowel or bladder disturbances; and preservation of large nerve fiber functions (normal strength, tendon reflexes, and vibration sense). [from GeneReviews]

ARVC may not cause any symptoms in its early stages. However, affected individuals may still be at risk of sudden death, especially during strenuous exercise. When symptoms occur, they most commonly include a sensation of fluttering or pounding in the chest (palpitations), light-headedness, and fainting (syncope). Over time, ARVC can also cause shortness of breath and abnormal swelling in the legs or abdomen. If the myocardium becomes severely damaged in the later stages of the disease, it can lead to heart failure.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a form of heart disease that usually appears in adulthood. ARVC is a disorder of the myocardium, which is the muscular wall of the heart. This condition causes part of the myocardium to break down over time, increasing the risk of an abnormal heartbeat (arrhythmia) and sudden death. [from MedlinePlus Genetics]

ARVC may not cause any symptoms in its early stages. However, affected individuals may still be at risk of sudden death, especially during strenuous exercise. When symptoms occur, they most commonly include a sensation of fluttering or pounding in the chest (palpitations), light-headedness, and fainting (syncope). Over time, ARVC can also cause shortness of breath and abnormal swelling in the legs or abdomen. If the myocardium becomes severely damaged in the later stages of the disease, it can lead to heart failure.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a form of heart disease that usually appears in adulthood. ARVC is a disorder of the myocardium, which is the muscular wall of the heart. This condition causes part of the myocardium to break down over time, increasing the risk of an abnormal heartbeat (arrhythmia) and sudden death. [from MedlinePlus Genetics]

Any hypertrophic cardiomyopathy in which the cause of the disease is a mutation in the MYL2 gene. [from MONDO]

Thyrotoxic periodic paralysis is a sporadic muscle disorder characterized by episodic attacks of weakness associated with hypokalemia in individuals with hyperthyroidism. The paralysis resolves upon treatment of hyperthyroidism. The disorder is most common among males of Asian descent, including Chinese, Japanese, Vietnamese, Filipino, and Koreans, although it occurs less commonly in individuals of Caucasian background. Thyrotoxic periodic paralysis is clinically similar to hereditary hypokalemic periodic paralysis (HOKPP; 170400), but the paralysis in TTPP occurs only in the presence of hyperthyroidism. TTPP can also be precipitated by factors that result in hypokalemia, such as carbohydrate ingestion and rest after exercise (review by Kung, 2006). Genetic Heterogeneity of Thyrotoxic Periodic Paralysis See also TTPP2 (613239), conferred by variation in the KCNJ18 gene (613236) on chromosome 17p11, and TTPP3 (614834), mapped to chromosome 17q24. [from OMIM]

Congenital long QT syndrome is electrocardiographically characterized by a prolonged QT interval and polymorphic ventricular arrhythmias (torsade de pointes). These cardiac arrhythmias may result in recurrent syncope, seizure, or sudden death (Jongbloed et al., 1999). For a discussion of genetic heterogeneity of long QT syndrome, see LQT1 (192500). [from OMIM]

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disturbance, affecting more than 2 million Americans, with an overall prevalence of 0.89%. The prevalence increases rapidly with age, to 2.3% between the ages of 40 and 60 years, and to 5.9% over the age of 65. The most dreaded complication is thromboembolic stroke (Brugada et al., 1997). For a discussion of genetic heterogeneity of atrial fibrillation, see 608583. [from OMIM]

ARVC may not cause any symptoms in its early stages. However, affected individuals may still be at risk of sudden death, especially during strenuous exercise. When symptoms occur, they most commonly include a sensation of fluttering or pounding in the chest (palpitations), light-headedness, and fainting (syncope). Over time, ARVC can also cause shortness of breath and abnormal swelling in the legs or abdomen. If the myocardium becomes severely damaged in the later stages of the disease, it can lead to heart failure.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a form of heart disease that usually appears in adulthood. ARVC is a disorder of the myocardium, which is the muscular wall of the heart. This condition causes part of the myocardium to break down over time, increasing the risk of an abnormal heartbeat (arrhythmia) and sudden death. [from MedlinePlus Genetics]

Any hypertrophic cardiomyopathy in which the cause of the disease is a mutation in the MYL3 gene. [from MONDO]

Wolff-Parkinson-White syndrome is a condition characterized by abnormal electrical pathways in the heart that cause a disruption of the heart's normal rhythm (arrhythmia).

The heartbeat is controlled by electrical signals that move through the heart in a highly coordinated way. A specialized cluster of cells called the atrioventricular node conducts electrical impulses from the heart's upper chambers (the atria) to the lower chambers (the ventricles). Impulses move through the atrioventricular node during each heartbeat, stimulating the ventricles to contract slightly later than the atria.

People with Wolff-Parkinson-White syndrome are born with an extra connection in the heart, called an accessory pathway, that allows electrical signals to bypass the atrioventricular node and move from the atria to the ventricles faster than usual. The accessory pathway may also transmit electrical impulses abnormally from the ventricles back to the atria. This extra connection can disrupt the coordinated movement of electrical signals through the heart, leading to an abnormally fast heartbeat (tachycardia) and other changes in heart rhythm. Resulting symptoms include dizziness, a sensation of fluttering or pounding in the chest (palpitations), shortness of breath, and fainting (syncope). In rare cases, arrhythmias associated with Wolff-Parkinson-White syndrome can lead to cardiac arrest and sudden death. The most common arrhythmia associated with Wolff-Parkinson-White syndrome is called paroxysmal supraventricular tachycardia.

Complications of Wolff-Parkinson-White syndrome can occur at any age, although some individuals born with an accessory pathway in the heart never experience any health problems associated with the condition.

Wolff-Parkinson-White syndrome often occurs with other structural abnormalities of the heart or underlying heart disease. The most common heart defect associated with the condition is Ebstein anomaly, which affects the valve that allows blood to flow from the right atrium to the right ventricle (the tricuspid valve). Additionally, the heart rhythm problems associated with Wolff-Parkinson-White syndrome can be a component of several other genetic syndromes, including hypokalemic periodic paralysis (a condition that causes episodes of extreme muscle weakness), Pompe disease (a disorder characterized by the storage of excess glycogen), Danon disease (a condition that weakens the heart and skeletal muscles and causes intellectual disability), and tuberous sclerosis complex (a condition that results in the growth of noncancerous tumors in many parts of the body). [from MedlinePlus Genetics]