Carney complex | |
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Other names | LAMB syndrome |
Carney complex with main associated diseases: Lentiginosis, myxoma of skin and heart, and primary pigmented nodular adrenocortical disease (PPNAD) | |
Specialty | Oncology, cardiology |
Carney complex and its subsets LAMB syndrome [1] and NAME syndrome [1] are autosomal dominant conditions comprising myxomas of the heart and skin, hyperpigmentation of the skin (lentiginosis), and endocrine overactivity. [2] [3] It is distinct from Carney's triad. Approximately 7% of all cardiac myxomas are associated with Carney complex. [4]
The spotty skin pigmentation and lentigines occur most commonly on the face, especially on the lips, eyelids, conjunctiva and oral mucosa. [3] Cardiac myxomas may lead to embolic strokes and heart failure [4] and may present with fever, joint pain, shortness of breath, diastolic rumble and tumor plop. Myxomas may also occur outside the heart, usually in the skin and breast. Endocrine tumors may manifest as disorders such as Cushing syndrome. The most common endocrine gland manifestation is an ACTH-independent Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). [5]
Manifestations of Carney complex [6] | Percentage [6] |
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Lentiginosis | 60-70% |
Cardiac myxoma | 30-60% |
Primary pigmented nodular adrenocortical disease (PPNAD) | 25-60% |
Ovarian cyst | 20-67% |
Skin myxoma | 20-63% |
Testicular tumor | 33-56% |
Ductal carcinoma of the breast | 25% |
Thyroid tumor | 10-25% |
Melanotic schwannoma | 8-18% |
Acromegaly | 10% |
Osteochondrotic myxoma | <10% |
Multiple blue nevi |
The LAMB acronym refers to lentigines, atrial myxomas, and blue nevi. [1] NAME refers to nevi, atrial myxoma, myxoid neurofibromas, and ephelides. [1]
Testicular cancer, particularly Sertoli cell type, is associated with Carney syndrome. [7] Thyroid and pancreas cancer may also occur. [8] [9]
Although J Aidan Carney also described Carney's triad it is entirely different. [10]
Carney complex is most commonly caused by mutations in the PRKAR1A gene on chromosome 17 (17q23-q24) [11] which may function as a tumor-suppressor gene. The encoded protein is a type 1A regulatory subunit of protein kinase A. Inactivating germline mutations of this gene are found in 70% of people with Carney complex. [12]
Less commonly, the molecular pathogenesis of Carney complex is a variety of genetic changes at chromosome 2 (2p16). [13] [14]
Both types of Carney complex are autosomal dominant. Despite dissimilar genetics, there appears to be no phenotypic difference between PRKAR1A and chromosome 2p16 mutations. [13]
Cardiac myxomas can be difficult to manage surgically because of recurrence within the heart, often far away from the site of the initial tumor. [3] [4]
In 1914 an American neurosurgeon, Harvey Cushing, reported on a patient with a pituitary tumour on whom he had operated. [15] The post mortem findings as reported were consistent with Carney complex, though at the time this condition had yet to be described. In 2017 archived tissue from the operation in Cushing's report was subjected to DNA sequencing, revealing an Arg74His (arginine to histidine: guanine (G)-> adenosine (A) transition in the second codon position of the 74th codon in the protein) mutation in the PRKAR1A gene, confirming a diagnosis of Carney complex. Therefore, Cushing's paper appears to be the first report of this complex.[ citation needed ]
Cushing's syndrome is a collection of signs and symptoms due to prolonged exposure to glucocorticoids such as cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, a round red face due to facial plethora, a fat lump between the shoulders, weak muscles, weak bones, acne, and fragile skin that heals poorly. Women may have more hair and irregular menstruation. Occasionally there may be changes in mood, headaches, and a chronic feeling of tiredness.
Multiple endocrine neoplasia is a condition which encompasses several distinct syndromes featuring tumors of endocrine glands, each with its own characteristic pattern. In some cases, the tumors are malignant, in others, benign. Benign or malignant tumors of nonendocrine tissues occur as components of some of these tumor syndromes.
A myxoma is a myxoid tumor of primitive connective tissue. It is most commonly found in the heart but can also occur in other locations.
Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms and the estimated prevalence rate in the general population is approximately 17%.
Adrenocortical carcinoma (ACC) is an aggressive cancer originating in the cortex of the adrenal gland.
A benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize. Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have relatively well differentiated cells. They are often surrounded by an outer surface or stay contained within the epithelium. Common examples of benign tumors include moles and uterine fibroids.
Succinate dehydrogenase [ubiquinone] cytochrome b small subunit, mitochondrial (CybS), also known as succinate dehydrogenase complex subunit D (SDHD), is a protein that in humans is encoded by the SDHD gene. Names previously used for SDHD were PGL and PGL1. Succinate dehydrogenase is an important enzyme in both the citric acid cycle and the electron transport chain. Hereditary PGL-PCC syndrome is caused by a parental imprint of the SDHD gene. Screening can begin by 6 years of age.
Succinate dehydrogenase complex subunit C, also known as succinate dehydrogenase cytochrome b560 subunit, mitochondrial, is a protein that in humans is encoded by the SDHC gene. This gene encodes one of four nuclear-encoded subunits that comprise succinate dehydrogenase, also known as mitochondrial complex II, a key enzyme complex of the tricarboxylic acid cycle and aerobic respiratory chains of mitochondria. The encoded protein is one of two integral membrane proteins that anchor other subunits of the complex, which form the catalytic core, to the inner mitochondrial membrane. There are several related pseudogenes for this gene on different chromosomes. Mutations in this gene have been associated with pheochromocytomas and paragangliomas. Alternatively spliced transcript variants have been described.
Multiple endocrine neoplasia type 1 (MEN-1) is one of a group of disorders, the multiple endocrine neoplasias, that affect the endocrine system through development of neoplastic lesions in pituitary, parathyroid gland and pancreas. Individuals suffering from this disorder are prone to developing multiple endocrine and nonendocrine tumors. It was first described by Paul Wermer in 1954.
McCune–Albright syndrome is a complex genetic disorder affecting the bone, skin and endocrine systems. It is a mosaic disease arising from somatic activating mutations in GNAS, which encodes the alpha-subunit of the Gs heterotrimeric G protein.
Noonan syndrome with multiple lentigines (NSML) which is part of a group called Ras/MAPK pathway syndromes, is a rare autosomal dominant, multisystem disease caused by a mutation in the protein tyrosine phosphatase, non-receptor type 11 gene (PTPN11). The disease is a complex of features, mostly involving the skin, skeletal and cardiovascular systems, which may or may not be present in all patients. The nature of how the mutation causes each of the condition's symptoms is not well known; however, research is ongoing. It is a RASopathy.
A myxoma is a rare benign tumor of the heart. Myxomata are the most common primary cardiac tumor in adults, and are most commonly found within the left atrium near the valve of the fossa ovalis. Myxomata may also develop in the other heart chambers. The tumor is derived from multipotent mesenchymal cells. Cardiac myxoma can affect adults between 30 and 60 years of age.
Rabson–Mendenhall syndrome is a rare autosomal recessive disorder characterized by severe insulin resistance. The disorder is caused by mutations in the insulin receptor gene. Symptoms include growth abnormalities of the head, face and nails, along with the development of acanthosis nigricans. Treatment involves controlling blood glucose levels by using insulin and incorporating a strategically planned, controlled diet. Also, direct actions against other symptoms may be taken This syndrome usually affects children and has a prognosis of 1–2 years.
The catalytic subunit α of protein kinase A is a key regulatory enzyme that in humans is encoded by the PRKACA gene. This enzyme is responsible for phosphorylating other proteins and substrates, changing their activity. Protein kinase A catalytic subunit is a member of the AGC kinase family, and contributes to the control of cellular processes that include glucose metabolism, cell division, and contextual memory. PKA Cα is part of a larger protein complex that is responsible for controlling when and where proteins are phosphorylated. Defective regulation of PKA holoenzyme activity has been linked to the progression of cardiovascular disease, certain endocrine disorders and cancers.
cAMP-dependent protein kinase type I-alpha regulatory subunit is an enzyme that in humans is encoded by the PRKAR1A gene.
Medullary thyroid cancer is a form of thyroid carcinoma which originates from the parafollicular cells, which produce the hormone calcitonin. Medullary tumors are the third most common of all thyroid cancers and together make up about 3% of all thyroid cancer cases. MTC was first characterized in 1959.
Carney triad (CT) is characterized by the coexistence of three types of neoplasms, mainly in young women, including gastric gastrointestinal stromal tumor, pulmonary chondroma, and extra-adrenal paraganglioma. The underlying genetic defect remains elusive. CT is distinct from Carney complex, and the Carney-Stratakis syndrome.
Mild androgen insensitivity syndrome (MAIS) is a condition that results in a mild impairment of the cell's ability to respond to androgens. The degree of impairment is sufficient to impair spermatogenesis and / or the development of secondary sexual characteristics at puberty in males, but does not affect genital differentiation or development. Female genital and sexual development is not significantly affected by the insensitivity to androgens; as such, MAIS is only diagnosed in males. The clinical phenotype associated with MAIS is a normal male habitus with mild spermatogenic defect and / or reduced secondary terminal hair.
Tegumental angiomyxoma-neurothekeoma is a syndrome, an acronym, and eponym proposed by Malaysian ophthalmologist of Chinese Descent, Tan Aik Kah. Angiomyxomas are associated with LAMB syndrome, NAME syndrome and Carney syndrome.
Primary pigmented nodular adrenocortical disease (PPNAD) was first coined in 1984 by Carney et al. it often occurs in association with Carney complex (CNC). CNC is a rare syndrome that involves the formation of abnormal tumours that cause endocrine hyperactivity.
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