Catecholamine

Catecholamine: Pronounced cat·e·chol·amine. An amine derived from the amino acid tyrosine — examples include epinephrine (adrenaline), norepinephrine (noradrenaline), and dopamine — that act as hormones or neurotransmitters. There are a number of disorders involving catecholamines, including neuroblastoma, pheochromocytoma, chemodectina, the familial paraganglioma syndrome, dopamine-�-hydroxalase deficiency, and tetrahydrobiopterin deficiency

Neuroblastoma is the second most common solid tumor in childhood (after brain tumors). It usually produce catecholamines. The catecholamine metabolites vanillylmandelic acid and homovanillic acid can be measured quantitatively in the urine as a test for the disease.

Pheochromocytoma is a benign tumor derived from the adrenal medulla or sympathetic paraganglia. The tumor secretes epinephrine and norepinephrine. These catecholamines cause attacks of hypertension, headache, nausea and vomiting, sweating, pallor and severe apprehension.

Chemodectoma is another benign tumor of the chemoreceptor system, the most common types being the carotid body tumor and the glomus jugulare tumor. Also known as nonchromaffin paraganglioma.

Familial paraganglioma syndrome is an unusual familial disease involving slow-growing benign tumors — paragangliomas, glomus tumors, or chemodectomas — predominantly in the head and neck region. The gene for the disease is on chromosome 11q23. The tumors may lead to disfiguring local swellings, cranial nerve injury, or involvement of the base of the skull and may cause dysphonia, aspiration, hearing loss, dysphagia, tinnitus, pain, persistent cough, and shoulder weakness (due to tumor encroachment on cranial nerves). All individuals with hereditary paragangliomas inherit the disease gene from their father. This is consistent with genomic imprinting: the maternally derived gene is inactivated during oogenesis and can be reactivated only during spermatogenesis.

Dopamine-�-hydroxalase deficiency is a congenital form of severe orthostatic hypotension caused by complete absence of the enzyme dopamine-�-hydroxalase. During childhood impaired exercise tolerance, fatigue, and episodes of syncope (fainting) are common. Symptoms from orthostatic hypotension become worse in late adolescence and in early adulthood.

Tetrahydrobiopterin deficiency is a genetic defect of enzymes required for the synthesis (production) of catecholamines, resulting in a deficiency in neurotransmitters. Symptoms begin between two and eight months of age, and include unstable body temperature, swallowing difficulties, hypersalivation, pinpoint pupils, ptosis of the eyelids, decreased mobility, drowsiness, and irritability.