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C A Stratakis

Publications and source records attributed to C A Stratakis.

At least 37 records · Page 2Linked to original sources
PubMed2001

Hamartoma and lentiginosis syndromes: clinical and molecular aspects.

The classic hamartoma syndromes and the related conditions discussed in this chapter show varying degrees of phenotypic and genetic overlap. Knowledge of the susceptibility genes underlying their phenotypes has provided additional information for the classification of these syndromes. Germline PTEN mutations appear to cause both CS and BRR. These two syndromes are therefore likely to be different manifestations of a single disease with variable expression. It has been suggested that PTEN mutation-positive CS and BRR should be grouped as a single entity for clinical purposes and classified as the 'PTEN hamartoma-tumour syndrome' [111]. Germline PTEN mutations are unlikely to cause JPS. However, germline SMAD4 mutation, especially a well-described 4-bp deletion, can be used to confirm a clinical diagnosis of JPS. Like the hamartoma syndromes, the lentiginoses also show substantial clinical overlap; it remains to be seen whether this is reflected in the molecular pathways that are involved in the pathogenesis of these syndromes. Given that the degree and type of cancer susceptibility between the hamartoma and lentiginosis syndromes is different, clarification of these syndromes at the molecular level is predicted to allow directed cancer surveillance. The molecular story is still evolving with regards to aspects of genetic heterogeneity, signalling pathways and the manner in which these hamartoma genes function in the development of their respective syndromes. It is likely that in all of these syndromes, tumours develop against a background created by loss of the growth-suppressive function of their susceptibility gene via mechanisms including disruption of the cell cycle and the activation of anti-apoptotic pathways.

Chromosome Mapping↗
PubMed2001

Spectrum of mutations of the AAAS gene in Allgrove syndrome: lack of mutations in six kindreds with isolated resistance to corticotropin.

Familial glucocorticoid deficiency due to corticotropin (ACTH) resistance consists of two distinct genetic syndromes that are both inherited as autosomal recessive traits: isolated ACTH resistance (iACTHR), which may be caused by inactivating mutations of the ACTH receptor (the MC2R gene) or mutations in an as yet unknown gene(s), and Allgrove syndrome (AS). The latter is also known as triple-A syndrome (MIM 231550). In three large cohorts of AS kindreds, the disease has been mapped to chromosome 12; most recently, mutations in the AAAS gene on 12q13 were found in these AS families. AAAS codes for the WD-repeat containing ALADIN (for alacrima-achalasia-adrenal insufficiency-neurologic disorder) protein. We investigated families with iACTHR (n = 4) and AS (n = 6) and a Bedouin family with ACTHR and a known defect of the TSH receptor. Four AS families were of mixed extraction from Puerto Rico (PR); most of the remaining six families were Caucasian families from North America (NA). Sequencing analysis found no MC2R genetic defects in any of the kindreds. No iACTHR kindreds, but all of AS families, had AAAS mutations. The previously reported IVS14+1G-->A splice donor mutation was found in all PR families, apparently due to a founder effect; one NA kindred was heterozygous for this mutation. In the latter family, long-range PCR failed to identify a deletion or other rearrangements of the AAAS gene. No other heterozygote or transmitting parent had any phenotype that could be considered part of AS. The IVS14+1G-->A mutation results in a premature termination of the predicted protein; although it was present in all PR families (in the homozygote state in three of them), there was substantial clinical variation between them. One PR family also carried a novel splice donor mutation of the AAAS gene in exon 11, IVS11+1G-->A; the proband was a compound heterozygote. A novel point mutation, 43C-->A(Gln15Lys), in exon 1 of the AAAS gene was identified in the homozygote state in a Canadian AS kindred with a milder AS phenotype. The predicted amino acid substitution in this family is located in a sequence that may participate in the preservation of stability of ALADIN beta-strands, whereas the splicing mutation in exon 11 may interfere with the formation of WD repeats in this molecule. We conclude that 1) AAAS does not appear to be frequently mutated in families with iACTHR; 2) AAAS is mutated in AS families from PR (that had previously been mapped to 12q13) and NA; and, 3) there is significant clinical variability between patients with the same AAAS defect.

Adrenocorticotropic Hormone↗
PubMed2001

Mutational analysis of the PRL receptor gene in human breast tumors with differential PRL receptor protein expression.

PRL is a major growth and differentiating hormone in the human breast, with activation of the PRL-PRL receptor complex increasingly recognized as an important mechanism in the induction and progression of mammary tumors. Although constitutive activation of various hormone and growth factor receptors is newly recognized as a common cause of tumor development, the PRL receptor gene has not been analyzed for similar aberrations in breast and other tumors. Therefore, using bacterial artificial chromosomes containing the PRL receptor gene and intron-spanning PCR, we determined the exon-surrounding intron sequences providing primers for the first analysis of the entire coding region of the human PRL receptor gene. We examined the presence of PRL receptor in 41 breast tumors by immunohistochemistry and attempted a correlation of its expression to pathological grading of the disease. Then tumor cells were isolated by laser capture microdissection to examine DNA from 30 patients for PRL receptor mutations. The PRL receptor immunoreactive score did not correlate to the tumor size, histopathological grading, age, or family history of patients. PRL receptor immunoreactivity was predominantly found in steroid hormone receptor-positive tumors, but without overall correlation of immunoreactive score. In both PRL receptor-positive and PRL receptor- negative breast cancer cells, direct sequencing of the coding sequence of the PRL receptor gene did not detect any somatic or hereditary gene aberrations. In conclusion, PRL receptor mutations do not appear to be common in human breast cancer, suggesting that constitutive activation of the PRL receptor can be excluded as a major cause of mammary tumor genesis. The molecular structure of the PRL receptor seems to remain intact in tumor tissue, and systemic and local production of PRL may participate in tumor cell growth and proliferation through functional receptors.

Adult↗
PubMed2001

Clinical and molecular features of the Carney complex: diagnostic criteria and recommendations for patient evaluation.

Carney complex is a multiple neoplasia syndrome featuring cardiac, endocrine, cutaneous, and neural tumors, as well as a variety of pigmented lesions of the skin and mucosae. Carney complex is inherited as an autosomal dominant trait and may simultaneously involve multiple endocrine glands, as in the classic multiple endocrine neoplasia syndromes 1 and 2. Carney complex also has some similarities to McCuneAlbright syndrome, a sporadic condition that is also characterized by multiple endocrine and nonendocrine tumors. Carney complex shares skin abnormalities and some nonendocrine tumors with the lentiginoses and certain of the hamartomatoses, particularly Peutz-Jeghers syndrome, with which it shares mucosal lentiginosis and an unusual gonadal tumor, large-cell calcifying Sertoli cell tumor. Careful clinical analysis has enabled positional cloning efforts to identify two chromosomal loci harboring potential candidate genes for Carney complex. Most recently, at the 17q22-24 locus, the tumor suppressor gene PRKAR1A, coding for the type 1alpha regulatory subunit of PKA, was found to be mutated in approximately half of the known Carney complex kindreds. PRKAR1A acts a classic tumor suppressor gene as demonstrated by loss of heterozygosity at the 17q22-24 locus in tumors associated with the complex. The second locus, at chromosome 2p16, to which most (but not all) of the remaining kindreds map, is also involved in the molecular pathogenesis of Carney complex tumors, as demonstrated by multiple genetic changes at this locus, including loss of heterozygosity and copy number gain. Despite the known genetic heterogeneity in the disease, clinical analysis has not detected any corresponding phenotypic differences between patients with PRKAR1A mutations and those without. This article summarizes the clinical manifestations of Carney complex from a worldwide collection of affected patients and also presents revised diagnostic criteria for Carney complex. In light of the recent identification of mutations in the PRKAR1A gene, an estimate of penetrance and recommendations for genetic screening are provided.

Adrenal Cortex Neoplasms↗
PubMed2001

Genetics of adrenocortical tumors: Carney complex.

Adrenal cancer is a rare neoplasm; however, up to 1 in 1 500 adrenal incidentalomas may hide a carcinoma, which, if diagnosed late or left untreated, is associated with significant morbidity and mortality. Despite extensive investigation of the molecular mechanisms involved in adrenal carcinogenesis and significant improvements in diagnostic imaging, efforts to cure advanced adrenal cancer remain largely unsuccessful. Thus, the investigation of the genetics of adrenocortical cancer by the candidate or positional cloning gene approach is essential in the development of new therapies for this disease. We propose that adrenocortical tumorigenesis follows a pattern similar to that in other organs: As the pathology of the adrenocortical tumor increases towards malignancy, the genetic changes that are observed also increase. Known genetic associations, like TP53 gene changes, occur during the latest stages of adrenocortical tumorigenesis. Thus, it is essential to study the relatively few genes that are affected at the beginning of this process, at the stages of benign tumorigenesis in the cortex. We have studied primary pigmented adrenocortical disease (PPNAD), a benign, bilateral, adrenocortical hyperplasia, which either in its isolated form or as part of Carney complex (CNC), is inherited in an autosomal dominant manner and, therefore, the gene(s) responsible for this disorder could be identified by positional cloning approaches. Indeed, we have identified two genetic loci harboring genes for PPNAD and/or CNC on chromosomal loci 2p16 and 17q22-24. The chromosome 17 gene, PRKAR1A, was recently cloned and the identification of other responsible genes is currently under way in our, and collaborating laboratories. The present report reviews the genetics of adrenocortical cancer first, followed by what is known today about the genetics of PPNAD and/or CNC.

Adrenal Cortex Diseases↗
PubMed2000

Genetic heterogeneity and spectrum of mutations of the PRKAR1A gene in patients with the carney complex.

Carney complex (CNC) is an autosomal dominant multiple neoplasia syndrome, which has been linked to loci on 2p16 and 17q22-24. We recently reported that PRKAR1A, which codes for the type 1A regulatory subunit of protein kinase A (PKA), is a tumor suppressor gene on chromosome 17 that is mutated in some CNC families. To evaluate the spectrum of PRKAR1A mutations, we identified its genomic structure and screened for mutations in 54 CNC kindreds (34 families and 20 patients with sporadic disease). Fourteen families were informative for linkage analysis: four of four families that mapped to 17q had PRKAR1A mutations, whereas there were no mutations found in seven families exhibiting at least one recombination with 17q. In six of the latter, CNC mapped to 2p16. PRKAR1A mutations were also found in 12 of 20 non-informative families and 7 of 20 sporadic cases. Altogether, 15 distinct PRKAR1A mutations were identified in 22 of 54 kindreds (40.7%). In 14 mutations, the sequence change was predicted to lead to a premature stop codon; one altered the initiator ATG codon. Mutant mRNAs containing a premature stop codon were unstable, as a result of nonsense-mediated mRNA decay. Accordingly, the predicted truncated PRKAR1A protein products were absent in these cells. We conclude that (i) genetic heterogeneity exists in CNC; and (ii) all of the CNC alleles on 17q are functionally null mutations of PRKAR1A. CNC is the first human disease recognized to be caused by mutations of the PKA holoenzyme, a critical component of cellular signaling.

Amino Acid Sequence↗
PubMed2000

Structure of the human ubiquitin fusion gene Uba80 (RPS27a) and one of its pseudogenes.

Ubiquitin is a highly conserved 76 amino acid protein that is generated in the cell by proteolysis of larger proteins containing either polyubiquitin chains or ubiquitin fused to carboxyl extension proteins (CEPs). In humans, the two human ubiquitin-CEP genes are Uba80 and Uba52, which code for ubiquitin fused to ribosomal protein S27a and L40, respectively. Working from a recently generated physical map of human chromosome 2p16, we determined the genetic and physical location and the genomic structure of the Uba80 gene in its entirety. A comparison of Uba80 to Uba52 revealed that the two genes share a conserved 5'-end structure, but that the structure of the ubiquitin coding regions was not conserved. Analysis of 400 bp of the promoter of Uba80 revealed strong similarity not only to the Uba52 promoter, but also to the other known human ribosomal gene promoters that have been identified to date. Homology searches also detected the presence of a pseudogene for Uba80, and the structure of this sequence feature is also reported.

Amino Acid Sequence↗
PubMed2000

[Primary pigmented nodular adrenocortical dysplasia (PPNAD) within the scope of Carney complex as the etiology of Cushing syndrome].

BACKGROUND: Primary pigmented adrenocortical dysplasia (PPNAD) represents a rare disorder of the adrenal glands and frequently occurs in patients with the so-called Carney complex. Carney complex is an autosomal dominant neoplasia syndrome including skin and mucosal lentigines, myxomas, and PPNAD. CASE REPORT: A 37-year-old woman suffered from several episodes of weight gain/depression and weight loss/mania indicating cyclic hypercortisolism. Finally, she developed a full-blown Cushing's syndrome (CS) treated by bilateral adrenalectomy. She had PPNAD in the setting of Carney complex. CONCLUSION: PPNAD may lead to different clinical manifestations: 1. subclinical hypercortisolism, 2. intermittent hypercortisolemia, and 3. full-blown CS. It can be diagnosed with the 6-day Liddle test that typically shows a paradoxical stimulation of cortisol secretion after dexamethasone administration. The treatment of choice for PPNAD is bilateral adrenalectomy in order to prevent devastating long-term effects of hypercortisolism.

Adrenal Cortex↗
PubMed2000

Genetics of Carney complex and related familial lentiginoses, and other multiple tumor syndromes.

Carney complex is a multiple endocrine neoplasia (MEN) syndrome that affects the adrenal cortex, the pituitary and thyroid glands, and the gonads. The complex is also associated with skin and mucosa pigmentation abnormalities and myxoid and other neoplasms of mesenchymal and neural crest origin. Thus, this syndrome also belongs to another group of genetic disorders, the lentiginoses (or lentigenoses), which include the Peutz-Jeghers, LEOPARD, arterial dissections and lentiginosis, and Laugier-Hunziker syndromes, Cowden disease and Ruvalcaba-Myhre-Smith (Bannayan-Zonana) syndrome and the centrofacial, benign patterned and segmental lentiginoses, all of which can be associated with a variety of developmental defects. The inheritance of Carney complex, just like that of the other MENs and the lentiginoses, is autosomal dominant. Genetic loci or genes have been identified for Carney complex, Peutz-Jeghers and Ruvalcaba-Myhre-Smith syndromes, but not for other lentiginoses. Elucidation of the molecular defects responsible for these disorders is expected to shed light on aspects of early neural crest differentiation, the regulation of pigmentation, the development of autonomous endocrine function, and endocrine and nonendocrine tumorigenesis.

Humans↗
PubMed2000

Genetic heterogeneity in Peutz-Jeghers syndrome.

LKB1, the human gene encoding a serine threonine kinase, was recently identified as a susceptibility gene for Peutz-Jeghers syndrome (PJS), a disease characterized by the constellation of intestinal hamartomata, oral mucocutaneous hyperpigmentation, and an increased risk for gastrointestinal as well as extraintestinal malignancies. To date, the majority of individuals with PJS have been found to have genetic alterations in LKB1, most of which result in protein truncation. Additionally, linkage analyses have suggested a modicum of genetic heterogeneity, with the majority of PJS families showing linkage to the LKB1 locus. In this study, we evaluated five kindreds with greater than two affected family members, five PJS probands with only one other affected family member, as well as 23 individuals with sporadic PJS for mutations within the LKB1 gene. Conformation sensitive gel electrophoresis was utilized for the initial screen, followed by direct sequence analysis for characterization. Long-range PCR was used for the detection of larger genetic insertions or deletions. Mutation analysis revealed genetic alterations in LKB1 in two probands who had a family history of PJS. LKB1 mutations were detected in only four of the remaining 23 cases of sporadic PJS. These data suggest the presence of significant genetic heterogeneity for PJS and the involvement of other loci in this syndrome.

AMP-Activated Protein Kinase Kinases↗
PubMed2000

Adrenal cancer.

Adrenal cancer is a rare neoplasm. Up to 1 in 1500 adrenal incidentalomas, however, may hide a carcinoma, which, if diagnosed late or left untreated, is associated with significant morbidity and mortality. Despite extensive investigation of the molecular mechanisms involved in adrenal carcinogenesis and significant improvements in diagnostic imaging, efforts to cure advanced adrenal cancer remain largely unsuccessful. This article reviews the recent advances in molecular understanding, clinical diagnosis, and treatment of adrenal cancer.

Adrenal Cortex Neoplasms↗
PubMed2000

Mutations of the gene encoding the protein kinase A type I-alpha regulatory subunit in patients with the Carney complex.

Carney complex (CNC) is a multiple neoplasia syndrome characterized by spotty skin pigmentation, cardiac and other myxomas, endocrine tumours and psammomatous melanotic schwannomas. CNC is inherited as an autosomal dominant trait and the genes responsible have been mapped to 2p16 and 17q22-24 (refs 6, 7). Because of its similarities to the McCune-Albright syndrome and other features, such as paradoxical responses to endocrine signals, genes implicated in cyclic nucleotide-dependent signalling have been considered candidates for causing CNC (ref. 10). In CNC families mapping to 17q, we detected loss of heterozygosity (LOH) in the vicinity of the gene (PRKAR1A) encoding protein kinase A regulatory subunit 1-alpha (RIalpha), including a polymorphic site within its 5' region. We subsequently identified three unrelated kindreds with an identical mutation in the coding region of PRKAR1A. Analysis of additional cases revealed the same mutation in a sporadic case of CNC, and different mutations in three other families, including one with isolated inherited cardiac myxomas. Analysis of PKA activity in CNC tumours demonstrated a decreased basal activity, but an increase in cAMP-stimulated activity compared with non-CNC tumours. We conclude that germline mutations in PRKAR1A, an apparent tumour-suppressor gene, are responsible for the CNC phenotype in a subset of patients with this disease.

Acromegaly↗
PubMed2000

A novel genetic locus for low renin hypertension: familial hyperaldosteronism type II maps to chromosome 7 (7p22).

Familial hyperaldosteronism type II (FH-II) is caused by adrenocortical hyperplasia or aldosteronoma or both and is frequently transmitted in an autosomal dominant fashion. Unlike FH type I (FH-I), which results from fusion of the CYP11B1 and CYP11B2 genes, hyperaldosteronism in FH-II is not glucocorticoid remediable. A large family with FH-II was used for a genome wide search and its members were evaluated by measuring the aldosterone:renin ratio. In those with an increased ratio, FH-II was confirmed by fludrocortisone suppression testing. After excluding most of the genome, genetic linkage was identified with a maximum two point lod score of 3.26 at theta=0, between FH-II in this family and the polymorphic markers D7S511, D7S517, and GATA24F03 on chromosome 7, a region that corresponds to cytogenetic band 7p22. This is the first identified locus for FH-II; its molecular elucidation may provide further insight into the aetiology of primary aldosteronism.

Chromosome Banding↗
PubMed2000

Adrenocorticotropin-independent macronodular adrenal hyperplasia: an uncommon cause of primary adrenal hypercortisolism.

PURPOSE: To describe the imaging findings in the adrenal glands of 12 patients with adrenocorticotropin (ACTH)-independent macronodular adrenocortical hyperplasia (AIMAH). MATERIALS AND METHODS: Computed tomographic (CT) and magnetic resonance (MR) imaging findings in the adrenal glands were reviewed retrospectively in 12 patients (three men, nine women) with ACTH-independent Cushing syndrome and with bilateral nonpigmented multinodular adrenal hyperplasia. The results of pituitary MR imaging, adrenal scintigraphy, and petrosal sampling were available in nine, five, and six patients, respectively. Eleven patients underwent bilateral and one patient underwent unilateral adrenalectomy. RESULTS: Eleven patients had enlarged multinodular adrenal glands: Nodules were 0.1-5.5 cm. The combined weight of both adrenal specimens for the 11 bilateral adrenalectomy specimens was 28-297 g, with a mean weight of 122 g. Glands were hypointense compared with the liver on T1-weighted images and were hyperintense on T2-weighted images. Pituitary MR imaging findings were negative in nine of nine patients. Iodomethylnorcholesterol scintigraphy showed bilateral uptake in four of five patients. Petrosal sinus sampling revealed no petrosal-to-peripheral ACTH gradients before corticotropin-releasing hormone (CRH) stimulation in six of six patients, but three patients had gradients after CRH stimulation. After undergoing bilateral or unilateral adrenalectomy, all patients were cured. CONCLUSION: AIMAH is a rare cause of ACTH-independent Cushing syndrome, with characteristic CT findings of massively enlarged multinodular adrenal glands. Bilateral adrenalectomy is indicated on the basis of clinical and CT findings.

Adrenal Glands↗