Noncanonical protein kinase A activation by oligomerization of regulatory subunits as revealed by inherited Carney complex mutations.

Familial mutations of the protein kinase A (PKA) R1α regulatory subunit lead to a generalized predisposition for a wide range of tumors, from pituitary adenomas to pancreatic and liver cancers, commonly referred to as Carney complex (CNC). CNC mutations are known to cause overactivation of PKA, but the molecular mechanisms underlying such kinase overactivity are not fully understood in the context of the canonical cAMP-dependent activation of PKA. Here, we show that oligomerization-induced sequestration of R1α from the catalytic subunit of PKA (C) is a viable mechanism of PKA activation that can explain the CNC phenotype. Our investigations focus on comparative analyses at the level of structure, unfolding, aggregation, and kinase inhibition profiles of wild-type (wt) PKA R1α, the A211D and G287W CNC mutants, as well as the cognate acrodysostosis type 1 (ACRDYS1) mutations A211T and G287E. The latter exhibit a phenotype opposite to CNC with suboptimal PKA activation compared with wt. Overall, our results show that CNC mutations not only perturb the classical cAMP-dependent allosteric activation pathway of PKA, but also amplify significantly more than the cognate ACRDYS1 mutations nonclassical and previously unappreciated activation pathways, such as oligomerization-induced losses of the PKA R1α inhibitory function.

A rare case of cutaneous myxoma with trichofolliculoma-like features.

Carney complex is a rare genetic disorder associated with a number of cutaneous lesions, especially cutaneous myxomas. We present a rare case of cutaneous myxoma (superficial angiomyxoma) with trichofolliculoma-like features in a patient with Carney complex, and explore how the associated histopathology provides critical context for elucidating the etiology of this benign neoplasm.

Recurrent multi-cameral cardiac myxomas in a child with Carney complex.

Cardiac myxoma is a relatively rare tumour, usually solitary, that occurs primarily in the left atrium of adults, but comprises only 30% of cardiac tumours in children. We recently treated a 12-year-old girl with multiple recurrent myxomas in three cardiac chambers(following surgical resection 3 years earlier). Genomic analysis showed the PKAR1A mutation typical for Carney complex.

Loss of PKA regulatory subunit 1α aggravates cardiomyocyte necrosis and myocardial ischemia/reperfusion injury.

Reperfusion therapy, the standard treatment for acute myocardial infarction, can trigger necrotic death of cardiomyocytes and provoke ischemia/reperfusion (I/R) injury. However, signaling pathways that regulate cardiomyocyte necrosis remain largely unknown. Our recent genome-wide RNAi screen has identified a potential necrosis suppressor gene PRKAR1A, which encodes PKA regulatory subunit 1α (R1α). R1α is primarily known for regulating PKA activity by sequestering PKA catalytic subunits in the absence of cAMP. Here, we showed that depletion of R1α augmented cardiomyocyte necrosis in vitro and in vivo, resulting in exaggerated myocardial I/R injury and contractile dysfunction. Mechanistically, R1α loss downregulated the Nrf2 antioxidant transcription factor and aggravated oxidative stress following I/R. Degradation of the endogenous Nrf2 inhibitor Keap1 through p62-dependent selective autophagy was blocked by R1α depletion. Phosphorylation of p62 at Ser349 by mammalian target of rapamycin complex 1 (mTORC1), a critical step in p62-Keap1 interaction, was induced by I/R, but diminished by R1α loss. Activation of PKA by forskolin or isoproterenol almost completely abolished hydrogen-peroxide-induced p62 phosphorylation. In conclusion, R1α loss induces unrestrained PKA activation and impairs the mTORC1-p62-Keap1-Nrf2 antioxidant defense system, leading to aggravated oxidative stress, necrosis, and myocardial I/R injury. Our findings uncover a novel role of PKA in oxidative stress and necrosis, which may be exploited to develop new cardioprotective therapies.

Phenotypic Variability in a Family with Carney Complex Accompanied by a Novel Mutation Involving PRKAR1A.

Carney complex is a rare, autosomal dominant disease accompanied by multiple endocrine neoplastic syndromes. Mutations in the PRKAR1A gene have recently been reported as a cause of Carney complex, but genotype-phenotype correlations vary widely. A 15-year-old Japanese man (Case 1) with short stature visited our hospital with suspected Cushing's syndrome. Biochemical investigations suggested corticotropin-independent Cushing's syndrome. Computed tomography revealed multiple bilateral adrenal tumors, and a two-staged partial adrenalectomy was performed. Pathological findings revealed primary pigmented nodular adrenocortical disease (PPNAD). The patient also exhibited distinctive spotty skin pigmentation. Based on these features, the patient was diagnosed as Carney complex. Cascade screening of family members was performed, and the mother (Case 2) and elder brother (Case 3) were diagnosed as Carney complex. Case 2 showed cardiac myxoma, acromegaly, spotty skin pigmentation, and mammary myxoid fibroadenoma. Case 3 exhibited gigantism, spotty skin pigmentation, and thyroid nodules. Target gene testing in Case 1 and 2 revealed the same novel mutation in PRKAR1A gene (c.503G>T, p.Gly168Val). This mutation was predicted as a pathogenic variant by multiple in silico analyses. Here, we present a family of Carney complex cases with a novel PRKAR1A pathogenic variant exhibiting varied clinical phenotypes within each case. In these cases, some specific phenotypes of Carney complex, such as pigmentary disorders, myxomas, and PPNAD are important as clues for diagnosis and prognostic factors. Clinicians should consider further examination in patients with Carney complex-specific phenotypes.

Bloody nipple discharge in Carney complex: A case report.

Carney complex (CNC) is an extremely rare, autosomal dominant genetic syndrome consisting of pigmented skin and mucosal changes with multiple endocrine and nonendocrine tumors, including the breast. Breast tumors are typically multiple and benign and are most commonly reported as myxoid fibroadenomas and/or intraductal papillomas. We present a young female patient with known CNC who presented with copious bloody nipple discharge with multiple breast lumps and discuss the breast imaging features regarding this complex and often underrecognized genetic condition.

Generalized congenital epithelioid blue nevi (pigmented epithelioid melanocytomas) in an infant: Report of case and review of the literature.

The epithelioid blue nevus (EBN) is a variant of the blue nevus characterized by heavily pigmented epithelioid melanocytes and lightly or nonpigmented spindle cells. It may be associated with Carney complex, a multiple neoplasia syndrome. Congenital cases of EBN not associated with Carney complex are rarely reported. We herein describe an infant who presented with multiple blue-gray nodules and papules involving the head, trunk, and extremities at birth, the corresponding histopathologic findings, and genetic testing results.

Growth hormone-producing pituitary adenomas in childhood and young adulthood: clinical features and outcomes.

PURPOSE: Growth hormone (GH)-producing pituitary adenomas (PAs) in childhood or young adulthood are rare, and the details surrounding these tumors remain enigmatic. We present the clinical, pathological and genetic features of this disease. METHODS: We identified 25 patients aged 20 years or younger with GH-producing PAs who underwent surgery between 2003 and 2016 at Toranomon Hospital in Tokyo. We retrospectively reviewed the clinical data, treatment outcomes and pathological features of these patients to shed light on childhood acromegaly. RESULTS: The cohort comprised 14 male and 11 female patients whose average age at the time of surgery was 17.3 years. Germline AIP mutations were present in 5 of 13 patients examined, and Carney complex was identified in 2 of 25 patients. The mean maximum tumor diameter was 26.7 mm, and total resection assessed during surgery was achieved in 17 patients. Based on their respective pathological findings, patients were divided into the following 4 groups: sparsely granulated adenomas (5), densely granulated (DG) adenomas (6), plurihormonal adenomas (9), and silent subtype 3 (SS3) adenomas (5). During the mean follow-up period of 50.3 months, complete endocrinological remission was achieved in 14 of 25 patients (56%) by surgery alone and in 19 patients (76%) after postoperative adjuvant therapy. CONCLUSIONS: GH-producing PAs in young patients are intriguing and difficult to treat due to their distinct tumor characteristics, including a lower incidence of the DG subtype and a higher incidence of SS3 adenomas and genetic abnormalities. Therefore, multi-modal therapies are essential to achieve optimal clinical outcomes.

Sporadic melanotic schwannoma with overlapping features of melanocytoma bearing a GNA11 mutation in an adolescent girl.

Melanotic schwannoma (MS) is a soft tissue neoplasm that shares histologic features with melanocytic tumors and schwannomas. A type of MS, called psammomatous MS (PMS), is associated with Carney complex (CNC), which is caused by PRKAR1A mutations. Other pigmented neoplasms, such as uveal melanomas and melanocytomas (MCs), are associated with genetic defects in other genes including GNA11. We report an adolescent female with a large sporadic mesenteric MS with complex histologic findings reminiscent of both PMS and MC. The lesion carried a mutation of the GNA11 gene. We conclude that sporadic MSs may occur rarely in adolescents without CNC; MSs may also be associated with somatic GNA11 mutations.

Unusual presentations of Carney Complex in patient with a novel PRKAR1A mutation.

Carney Complex (CNC) is a multiple neoplasia syndrome characterized by skin tumors and pigmented lesions, myxomas, and various endocrine tumors. The aim of this case report was to describe a case of CNC with a novel PRKAR1A mutation. A man aged 46 years with a medical history of surgery for cardiac myxomas at the age of 39 was admitted to our hospital because of four newly-developed heart masses. The histologic examination confirmed cardiac myxomas. He had many presentations of CNC such as growth hormone (GH) and prolactin (PRL)-secreting mixed pituitary adenoma, benign thyroid nodule, large-cell calcifying Sertoli cell tumor (LCCST), and superficial angiomyxoma. A bilateral adrenalectomy was performed because the laboratory findings suggested primary pigmented nodular adrenocortical disease (PPNAD). The pathologic examination revealed a focal unilateral PPNAD, unilateral nonpigmented adrenocortical nodule, and bilateral adrenal medullary hyperplasia. Two years after the second cardiac operation, an interatrial septum-derived tumor was detected. An atrial myxoma was confirmed with histologic studies. Based on these findings, the patient was confirmed to have CNC. A novel insertion mutation in the type 1A regulatory subunit of the cAMP-dependent protein kinase A gene (PRKAR1A) in exon 2 was detected in our patient through genetic analysis. The presence of multiple myxomas and endocrine abnormalities should be an indication to physicians to further investigate for CNC. Herein, we described a case of CNC with a novel mutation in exon 2 of the PRKAR1A gene with typical and atypical clinical features.

[A Case of a Pituitary Adenoma Diagnosed as Carney Complex Syndrome in an Older Female Patient].

Carney complex syndrome is an autosomal dominant familial tumor syndrome first described by Carney et al. in 1985. The diagnostic criteria include endocrine hyperactivity and spotty skin pigmentation. A 73-year-old woman with cerebral infarction was referred to our department because her brain magnetic resonance imaging(MRI)revealed a pituitary tumor. Her blood tests revealed elevated levels of growth hormone(GH), thyroid stimulating hormone(TSH), and insulin-like growth factor-1(IGF-1). We suspected the presence of a GH-secreting tumor and performed the operation. The pathological finding was a TSH-positive pituitary adenoma. Her cervical computed tomography(CT)revealed a thyroid tumor and the tumor removal was performed. The pathological diagnosis was papillary carcinoma. She had skin pigmentation bilaterally on her face, forearms, hands, and legs. We diagnosed this case as Carney complex syndrome based on these findings.

Carney complex: A familial lentiginosis predisposing to a variety of tumors.

Carney complex is a familial lentiginosis syndrome; these disorders cover a wide phenotypic spectrum ranging from a benign inherited predisposition to develop cutaneous spots not associated with systemic disease to associations with several syndromes. Carney complex is caused by PRKAR1A mutations and perturbations of the cyclic AMP-dependent protein kinase (PKA) signaling pathway. In addition to the cutaneous findings, the main tumors associated with Carney complex are endocrine: 1) primary pigmented nodular adrenocortical disease, a bilateral adrenal hyperplasia leading to Cushing syndrome; 2) growth-hormone secreting pituitary adenoma or pituitary somatotropic hyperplasia leading to acromegaly; 3) thyroid and gonadal tumors, including a predisposition to thyroid cancer. Other tumors associated with Carney complex include: 1) myxomas of the heart, breast and other sites; 2) psamommatous melanotic schwannomas which can become malignant; 4) a predisposition to a variety of cancers.

MEN1, MEN4, and Carney Complex: Pathology and Molecular Genetics.

Pituitary adenomas are a common feature of a subset of endocrine neoplasia syndromes, which have otherwise highly variable disease manifestations. We provide here a review of the clinical features and human molecular genetics of multiple endocrine neoplasia (MEN) type 1 and 4 (MEN1 and MEN4, respectively) and Carney complex (CNC). MEN1, MEN4, and CNC are hereditary autosomal dominant syndromes that can present with pituitary adenomas. MEN1 is caused by inactivating mutations in the MEN1 gene, whose product menin is involved in multiple intracellular pathways contributing to transcriptional control and cell proliferation. MEN1 clinical features include primary hyperparathyroidism, pancreatic neuroendocrine tumours and prolactinomas as well as other pituitary adenomas. A subset of patients with pituitary adenomas and other MEN1 features have mutations in the CDKN1B gene; their disease has been called MEN4. Inactivating mutations in the type 1α regulatory subunit of protein kinase A (PKA; the PRKAR1A gene), that lead to dysregulation and activation of the PKA pathway, are the main genetic cause of CNC, which is clinically characterised by primary pigmented nodular adrenocortical disease, spotty skin pigmentation (lentigines), cardiac and other myxomas and acromegaly due to somatotropinomas or somatotrope hyperplasia.

Case studies of two related Chinese patients with Carney complex presenting with extensive cardiac myxomas and PRKAR1A gene mutation of c.491_492delTG.

Carney complex is an autosomal dominant disease that is clinically characterized by cardiac myxomas, spotty skin pigmentation, and endocrine overactivity. Carney complex is most commonly caused by mutations in the PRKAR1A gene on chromosome 17q22-24. Currently, there are at least 117 pathogenic mutations in PRKAR1A that have been identified. Herein, we report on two cases of Carney complex in related Chinese patients with a c.491_492delTG mutation that presented with multiple and extensive cardiac myxomas and skin pigmentation.

Tumorectomy with right thoracotomy for synchronous left atrial myxomas from Carney complex: report of a case.

This report describes a case of synchronous left atrial myxomas from Carney complex resected through a right thoracotomy. The patient was a 30-year-old female that had previously been diagnosed with Carney complex following a genetic examination. Preoperative echocardiography showed a left atrial tumor, but intraoperative inspection revealed another tumor in the left atrium. Carney complex was first described in the 1980s and cardiac myxoma from Carney complex can occur in any cardiac chamber, presenting multiple times with postoperative recurrences, occurring at any age and without any predilection for gender, and is inherited in an autosomal-dominant manner. Treatment for cardiac myxoma from Carney complex is very important for patient mortality and morbidity and, despite the endocrine nature of the disorder, cardiologists and cardiac surgeons play an important role.

Carney complex: A clinicopathologic study on a single family from several Canadian provinces.

Carney syndrome is an autosomal dominant complex involving endocrinopathy, mucocutaneous hyperpigmentation, and different tumors, including cardiac myxomas. We report on a single family with several members affected with Carney syndrome. Family and individual medical histories were investigated in several Canadian provinces. The histology slides were also reviewed. Four family members (two young women, both sisters, their mother, and maternal grandmother) were found to harbor Carney syndrome. Everyone was presented with multiple and recurrent atrial myxomas of the heart, requiring multiple open cardiac surgeries. Breast myxomas and cutaneous hyperpigmentation were also revealed in one of the sisters and their mother. Interestingly, genetic testing was positive for the female family members and negative for the father and brother. We cannot rule out that the brother may have had a new mutation or harboring a mosaic. The young woman's brother did not have cardiac myxoma but developed a unilateral Sertoli cell tumor of testis. Carney syndrome is a rare complex multisystemic genetic disorder, including multiple and recurrent cardiac myxomas. We strongly suggest that reporting familial Carney syndrome is still critical in the 21st century to augment the awareness of this situation among clinicians and pathologists.

Molecular characterization of large cell calcifying sertoli cell tumors: A multi-institutional study of 6 benign and 2 malignant tumors.

Large cell calcifying Sertoli cell tumors (LCCSCTs) are rare testicular tumors, representing <1 % of all testicular neoplasms. Almost 40 % of patients with LCCSCTs will present in the context of the inherited tumor predisposition syndrome, the Carney complex. While most LCCSCTs are benign, 10-20 % have malignant behavior. The aim of our study was to analyze LCCSCTs for novel molecular alterations in addition to PRKAR1A mutations and to identify potential drivers for malignant progression. Eight LCCSCTs diagnosed at two institutions were included. Two patients had the Carney complex confirmed on subsequent genetic testing, and two tumors had several adverse pathological findings. One patient presented with metastatic disease at the time of initial diagnosis. Targeted next-generation sequencing detected PRKAR1A alterations in all cases, with heterozygous PRKAR1A mutations in 5 tumors, germline Carney-complex-associated PRKAR1A mutation in 2 patients, and PRKAR1A fusion in 1 tumor. Additionally, sequencing the metastatic case identified CDKN1B and TERT promoter gene mutations. All tumors showed a low tumoral mutational burden and unremarkable copy number alterations except for frequent LOH of 17q24 encompassing the PRKAR1A locus. RNA expression analysis showed increased expression of several markers including novel PRUNE2, and usual markers like inhibin and calretinin. Our study showed that while LCCSCTs have been reported in the setting of cancer predisposition syndromes, the majority of these tumors occur sporadically. PRKAR1A alterations were present in all cases and appear to be the major driver in LCCSCTs. It remains to be determined whether malignant progression may be caused by additional driver mutations.

Frequent protein kinase A regulatory subunit A1 mutations but no GNAS mutations as potential driver in sporadic cardiac myxomas.

PURPOSE: Cardiac myxomas (CMs) are the second most common benign primary cardiac tumors, mainly originating within the left atrium. Approximately 5% of CM cases are associated with Carney Complex (CNC), an autosomal dominant multiple neoplasia syndrome often caused by germline mutations in the protein kinase A regulatory subunit 1A (PRKAR1A). Data concerning PRKAR1A alterations in sporadic myxomas are variable and sparse, with PRKAR1A mutations reported to range from 0% to 87%. Therefore, we investigated the frequency of PRKAR1A mutations in sporadic CM using next-generation sequencing (NGS). Additionally, we explored mutations in the catalytic domain of the Protein Kinase A complex (PRKACA) and examined the presence of GNAS mutations as another potential driver. METHODS AND RESULTS: This study retrospectively collected histological and clinical data from 27 patients with CM. First, we ruled out the possibility of underlying CNC through clinical evaluations and standardized interviews for each patient. Second, we performed PRKAR1A immunohistochemistry (IHC) analysis and graded the reactivity of myxoma cells semi-quantitatively. NGS was then applied to analyze the coding regions of PRKAR1A, PRKACA, and GNAS in all 27 cases. Of the 27 sporadic CM cases, 13 (48%) harbored mutations in PRKAR1A. Among these 13 mutant cases, six displayed more than one mutation in PRKAR1A. Most of the identified mutations resulted in premature stop codons or affected splicing. In PRKAR1A mutant CM cases, the loss of PRKAR1A protein expression was significantly more common. In two cases with missense mutations, protein expression remained preserved. Furthermore, a single mutation was detected in the catalytic domain of the protein kinase A complex, while no GNAS mutations were found. CONCLUSION: We identified a relatively high frequency of PRKAR1A mutations in sporadic CM. These PRKAR1A mutations may also represent an important oncogenic mechanism in sporadic myxomas, as already known in CM cases associated with CNC.

[Psammomatous melanotic schwannoma as indicator of a Carney complex]. / Psammomatöses melanotisches Schwannom als Indikator eines Carney-Komplexes.

Within a few months a 31-year-old female patient was diagnosed with a psammomatous melanotic schwannoma, an atrial myxoma and microfollicular adenomas in both thyroid lobes. Therefore, sufficient diagnostic criteria of a Carney complex were fulfilled. The Carney complex is an inherited autosomal dominant disorder with highly variable phenotypes, which was initially described by Carney in 1985 as a complex of myxomas, spotty skin pigmentation and endocrine overactivity. Pathologists should consider this differential diagnosis in reports when confronted with a psammomatous melanotic schwannoma.