HEREDITARY DEFICIENCIES OF CLOTTING FACTORS VII AND X ASSOCIATED WITH CAROTID-BODY TUMORS

Endocrine hypertension: then and now

OBJECTIVE

To review the first reported cases of successfully treated pheochromocytoma and primary aldosteronism and to document the diagnostic and therapeutic advances that have occurred since the initial descriptions.

METHODS

The original case descriptions and the subsequent pertinent literature were reviewed.

RESULTS

The successful management of the initial cases of pheochromocytoma in 1926 and primary aldosteronism in 1954 was highlighted by keen clinical observation, clinical intuition, and application of scientific principles. Since those prismatic case descriptions, the technological advances in laboratory-based diagnosis, radiology-based tumor localization, and surgical approaches to the adrenal glands have been truly remarkable.

CONCLUSIONS

The evolution in the diagnosis and treatment of pheochromocytoma will continue to progress as we identify more genetic causes, develop biochemical markers for "preclinical" pheochromocytoma, identify better markers for malignant disease, and develop more effective treatment options for malignant pheochromocytoma. Over the next decade, we hope to determine the pathophysiology for bilateral idiopathic hyperaldosteronism, develop less invasive and less technically demanding tests to distinguish between unilateral aldosterone-producing adenoma and bilateral idiopathic hyperaldosteronism, determine where low renin hypertension stops and primary aldosteronism starts, and determine the impact of genetic and environmental factors on aldosterone secretion in patients with and without primary aldosteronism.

SDH-related pheochromocytoma and paraganglioma

Pheochromocytoma and paraganglioma are rare tumors of adrenals as well as the sympathetic and parasympathetic paraganglia. Clinical presentation of these tumors depends on localization, secretory profile and malignant potential. Four distinct syndromes--PGL1-4--are related to mutations in the succinate dehydrogenase gene--mitochondrial complex involved in electron transfer and Krebs cycle. Here we describe etiology, genetics, as well as clinical aspects of SDH-related tumors. We also describe recent discoveries in HIF-related pathway of tumorigenesis and mutations in new SDH-related genes that have improved our understanding of this disease.

Congenital combined defects of factor VII: a critical review

Factor VII deficiency is the least rare among uncommon congenital coagulation disorders. The majority of cases are isolated deficiencies. In some cases, FVII deficiency has been found to be associated with the deficiency in another coagulation factor or with non-coagulation-related abnormalities or defects. The evaluation of all published studies on the subject has shown that the FVII defect has been reported in association with FV, FVIII, FIX, FX, FXI and protein C defects. Furthermore, FVII deficiency has been described in association with bilirubin metabolism disorders, mental retardation, microcephaly, epicanthus, cleft palate and persistence of ductus arteriosus. The most interesting association appears to be that with FX. This has been shown to be due to a deletion in part of the long arm of chromosome 13. This arm contains genes coding for both FVII and FX. Interestingly, this combined coagulation defect has been found to be associated with carotid body tumors and several other malformations. Combined defects in blood coagulation often create diagnostic difficulties since results cannot be explained if a single factor deficiency is assumed. For example the combined FVII and FX defect yields a rather peculiar laboratory picture (prolonged prothrombin time and partial thromboplastin time, but normal thrombin time) that could suggest FII or FV or FX single deficiency and not FVII deficiency, indicating the need for specific factor assays whenever data are confusing. Finally, the elevated incidence of mental and skeletal malformations present in these combined defects indicates the need for a careful evaluation of all these patients lest some aspects of the defect are missed.

Genetic analysis of mitochondrial complex II subunits SDHD, SDHB and SDHC in paraganglioma and phaeochromocytoma susceptibility

BACKGROUND

Germline mutations in three subunits of mitochondrial complex II (SDHB, SDHC and SDHD) may be associated with susceptibility to phaeochromocytoma (PC) and/or head and neck paraganglioma (HNPGL).

METHODS

To further define the role of SDH subunit mutations in these disorders, we analysed a series of 22 probands with PC and evidence of genetic susceptibility (seven with familial PC only, one with familial PC and HNPGL, 10 sporadic cases with multiple PC and four cases of isolated paediatric onset PC) for germline SDHB, SDHC and SDHD mutations. In addition, we analysed 34 cases of HNPGL (30 isolated cases with single tumours, three isolated cases with multiple tumours and one familial case with multiple tumours) for somatic and germline mutations in SDHB, SDHC and SDHD.

RESULTS

We identified four germline mutations (three SDHB and one SDHD, three novel) in the 22 PC probands. Combining these results with our previous series, we have detected germline SDHB or SDHD mutations in 2/12 (17%) of familial PC only kindreds, 4/5 (80%) of familial PC and HNPGL cases, 1/10 of sporadic multiple PC cases and 2/4 (50%) of paediatric PCs. No somatic mutations were detected in the HNPGL tumours, but four cases with multiple HNPGL had the common P81L germline SDHD mutation. Intriguingly a silent SNP (c.204C > T) in SDHD was significantly more common in HNPGL cases (6/34) than in controls (1/100, P = 0.0011). Combining our results with those from two other large studies in which both SDHB and SDHD have been analysed, SDHB mutations were most commonly associated with phaeochromocytoma susceptibility and SDHD with the development of HNPGL (P = 0.025). However, germline SDHB and SDHD mutations demonstrate considerable phenotypic variability and genotype-phenotype correlations are complex.

CONCLUSION

The significantly lower frequency (P = 0.028) of germline SDH subunit mutations in familial PC only cases compared to those with familial PC and HNPGL suggests that further PC susceptibility gene(s) remain to be identified.

A role for mitochondrial enzymes in inherited neoplasia and beyond

Mitochondrial defects have been associated with neurological disorders, as well as cancers. Two ubiquitously expressed mitochondrial enzymes--succinate dehydrogenase (SDH) and fumarate hydratase (FH, fumarase)--catalyse sequential steps in the Krebs tricarboxylic-acid cycle. Inherited heterozygous mutations in the genes encoding these enzymes cause predispositions to two types of inherited neoplasia syndromes that do not share any component tumours. Homozygous mutations in the same genes result in severe neurological impairment. Understanding this link between inherited cancer syndromes and neurological disease could provide further insights into the mechanisms by which mitochondrial deficiencies lead to tumour development.

A novel mutation in the SDHD gene in a family with inherited paragangliomas--implications of genetic diagnosis for follow up and treatment

BACKGROUND

Early detection of paragangliomas (PGs) has been linked to low morbidity after surgical resection. Recent identification of causative genes (SDHB, SDHC, and SDHD) has made it possible to detect individuals at high risk for tumors.

METHODS

We identified a three-generation family, with four individuals affected with PGs. Because pedigree analysis suggested maternal imprinting (the phenotype is present only if inherited through the paternal line), the SDHD gene (PGL1) was screened.

RESULTS

A novel mutation that causes skipping of exon 3 was identified. Ten of the seventeen tested individuals carried the mutation. All six clinically unaffected individuals inherited the mutation from their mother. Five of them are men, with a 50% risk for affected progeny.

CONCLUSIONS

To allow early treatment with low morbidity, genetic counseling is needed when familial paraganglioma is suspected. Asymptomatic carriers should be followed by cervical MRI. In addition, because pheochromocytomas may occur, catecholamine excretion can be performed. This screening should probably be proposed at 5 to 10 years of age.

Familial paraganglioma and gastric stromal sarcoma: a new syndrome distinct from the Carney triad

Paragangliomas may be inherited in an autosomal dominant manner either alone (as in PGL1, PGL2, and PGL3 syndromes) or as a component of a multiple tumor syndrome (as in von Hippel-Lindau disease and neurofibromatosis type 1). In this article, we describe 12 patients (7 male and 5 female) with an average age of 23 years from five unrelated families that manifested paraganglioma and gastric stromal sarcoma; the tumors were inherited in an apparent autosomal dominant manner, with incomplete penetrance. Seven patients had paraganglioma, four had paraganglioma and gastric stromal sarcoma, and one had gastric stromal sarcoma. The paraganglioma was multicentric and the gastric stromal sarcoma multifocal. Because of the rarity of gastric stromal sarcoma and its multifocality, the young age of the patients, and the unlikelihood of coincidental co-occurrence of paragangliomas and gastric stromal sarcomas, we suggest that a new syndrome exists with these two main components, a condition that is familial and distinct from the Carney triad.

Genetics of familial paragangliomas: past, present, and future

Genetic studies of hereditary paraganglioma tumors could increase the understanding of the biology of these fascinating tumors, with important clinical implications for diagnosis and treatment. This article focuses on the genetics of paraganglioma tumors, with limited reference to their general morphologic and clinical aspects. The paraganglioma tumor phenotype is defined. The genetic and physical mapping studies recently performed are summarized--studies that eventually led to the discovery of the gene for hereditary paraganglioma type 1 (PGL1). Finally, future directions stemming from the PGL gene discovery are described.

Familial carotid body tumors: incidence and implications

Carotid body tumors may occur sporadically (90%) or in a familial pattern (10%). One third of the patients with familial disease have bilateral tumors. We report the case of a patient with bilateral carotid body tumors and a strong family history of such tumors. Details of his evaluation and treatment are reviewed. Relatives of patients with carotid body tumors should be examined carefully, and any suspicious neck mass should be appropriately investigated.

Production and characterization of a human monoclonal antibody recognizing a new antigen expressed on some lymphoid cells

A cell line secreting a human monoclonal antibody was established by Epstein-Barr virus transforming B cells derived from an enlarged cervical lymph node excised from a patient bearing a carotid body tumor. The reactivity of the monoclonal antibody, designated as mNISP, was tested on various cells and cell lines. An antigen defined by the mNISP was expressed on some Burkitt's lymphoma cell lines and on a non-T non-B acute lymphoblastic leukemia cell line. Furthermore, this antigen was expressed on leukemic cells from 2 of 8 patients with chronic myelocytic leukemia, 2 of 10 patients with acute myeloblastic leukemia, one of 13 patients with acute lymphoblastic leukemia, and two patients with adult T cell leukemia, but it was not expressed on normal T, B and adherent (macrophage) cells. In addition, mNISP reacted with T cells obtained from human T-cell leukemia virus type I carriers. We found that the antigen defined by mNISP was distinct from any previously reported antigen in terms of its pattern of cellular expression and molecular weight, suggesting that mNISP recognizes a new antigen expressed on some lymphoid cells.

Genomic imprinting in hereditary glomus tumours: evidence for new genetic theory

A study based on fifteen pedigrees showed that familial glomus tumours are inherited almost exclusively via the paternal line, a finding inconsistent with autosomal dominant transmission. The results can be explained in terms of the genomic imprinting hypothesis--the maternally derived gene is inactivated during female oogenesis and can be reactivated only during spermatogenesis. Genomic imprinting may have considerable implications for genetic counselling with respect to glomus tumours and also for the understanding of other hereditary diseases.

Radionuclide angiography and surgery for familial bilateral chemodectomas

Carotid body tumours, or chemodectomas, can occur on both sides of the neck (5%), and this bilaterality increases sixfold (30%) where a familial pattern is evident. The known pathological behaviour of chemodectomas makes early recognition and management desirable, especially when an inherited predisposition can be anticipated. Difficulties in clinical diagnosis and the hazards of blind exploration have imposed a reliance on contrast angiography, which is a potentially dangerous procedure. The family tree of a patient with bilateral chemodectomas was traced and 28 individuals were studied using radionuclide angiography (99mTechnetium gluconate), a quick, safe technique with a high yield. Bilateral chemodectomas were observed in five siblings, establishing conclusively the existence of a dominant hereditary trait. Excision of newly discovered tumours was accomplished without complication. The techniques which permitted such a favourable surgical outcome are discussed, emphasising the view that these tumours are best dealt with by vascular surgeons.

Novel factor X deficiency. Normal partial thromboplastin time and associated spindle cell thymoma

This report presents a heretofore undescribed laboratory variant of congenital factor X deficiency, seen in conjunction with a relatively rare tumor. The patient had a history of bleeding, a prolonged prothrombin time, and a factor X value of 4.2 percent of normal activity, but the partial thromboplastin time and Russell's viper venom clotting time were normal. Management of this case required unusual measures to treat the patient's coagulopathy.

Studies on a family with combined functional deficiencies of vitamin K-dependent coagulation factors

Two siblings with m ild hemorrhagic symptoms had combined functional deficiencies of vitamin K-dependent clotting factors. Prothrombin (0.18-0.20 U/ml) and Stuart factor (Factor X, 0.18-0.20 U/ml) and Stuart factor (Factor X, 0.18-0.20 U/ml) were most severely affected. Antigenic amounts of affected coagulation factors were normal and normal generation of thrombin activity occurred in the patients' plasmas after treatment with nonophysiologic activators that do not require calcium for prothrombin activation. Hepatobilary disease, malabsorptive disorders, and plasma warfarin were not present. Both parents had normal levels of all coagulation factors. The patients' plasmas contained prothrombin that reacted both with antibody directed against des-gamma-carboxyprothrombin and native prothrombin. Crossed immunoelectrophoresis of patients' plasmas and studies of partially purified patient prothrombin suggested the presence of a relatively homogeneous species of dysfunctional prothrombin, distinct from the heterologous species found in the plasma of warfarin-treated persons. These studies are most consistent with a posttranslational defect in hepatic carboxylation of vitamin K-dependent factors. This kindred uniquely possesses an autosomal recessive disorder of vitamin K-dependent factor formation that causes production of an apparently homogeneous species of dysfunctional prothrombin; the functional deficiencies in clotting factors are totally corrected by oral or parenteral administration of vitamin K1.

New methods in coagulation

Recent advances in the elucidation of the molecular biochemistry of the coagulation proteins have provided the foundation for the development of synthetic substrates. These substrates are oligopeptide with either a chromophore or fluorophore group attached to the C-terminal end. They may be used in the laboratory to assay for a number of the serine proteases involved in either coagulation or fibrinolysis. Also, by suitably modifying the assay system, the various inhibitors can be quantitated. These substrates promise to revolutionize the coagulation laboratory allowing for more precise quantitation of trace enzymes and also improved standardization and precision of coagulation assays. In addition to these substrates, the introduction of a number of immunologic procedures into the diagnostic laboratory have been of major importance in elucidating the heterogeneity of hereditary coagulation defects. By correlating the immunologic assays, coagulation assays and clinical picture, a number of subgroups of hereditary deficiencies have been identified. Also, the immunologic assays have provided a means for identifying the carrier state of hemophilia A and have significantly contributed to the improved diagnosis of von Willebrand's disease. The use of ristocetin cofactor assays, when used in conjunction with the Factor VIII antigens, have enable the laboratory to more accurately diagnose the majority of patients with von Willebrand's disease. Ristocetin cofactor may be assayed utilizing either formalin fixed or washed platelets and recently a snake venom has been introduced to assay for this particular aspect of the Factor VIII complex. Platelet specific proteins (i.e., platelet factor 4 and beta-thromboglobulin) may be assayed utilizing either radioimmunoassays or in the case of platelet factor 4 modified coagulation assays. These proteins provide evidence of in vivo platelet activation and hopefully may, in the future, be correlated with platelet kinetics.

Familial carotid body tumors: case report and epidemiologic review

We report on the cases of two sisters with carotid body tumor (CBT) and present a literature review that assembles epidemiologic information on 88 familial and 835 nonfamilial CBT patients. The sex ratio (males/females) of 1.0 for familial CBT (0.7 for nonfamilial) and CBT reports with complete sibship information suggest autosomal dominant genetic transmission. As in other familial cancers, bilateral disease is significantly more frequent in familial (31.8% of cases) than in nonfamilial CBT (4.4%). However, there is no difference in age at diagnosis between familial and nonfamilial CBR. Thus, this adult-onset familial cancer does not completely fit the Knudson "two-step mutation" model of carcinogenesis. We also found that 6% of reported CBT patients developed second primary tumors, mostly other paragangliomas. This feature suggests that CBT may be part of a larger neurocristopathy syndrome of multiple tumors of cells of neural crest origin.

Paragangliomas of the head and neck region: a clinical study of 69 patients

Over a 38-year-period 73 paragangliomas from the head and neck region were seen at Memorial Hospital. These occurred in 69 patients. There were 44 carotid body, 13 vagal body, eight jugulo-tympanic, and three nasal paragangliomas. In addition, one each arose in the orbit, larynx, and area of the aortic arch. Sixty-two patients were surgically treated while three received irradiation only and four were observed but not treated. Follow-up was obtained for 94% of the patients. There were six postoperative deaths, five of which occurred before 1945. Of those treated surgically, 37 had no evidence of recurrent tumor while the paragangliomas recurred locally in 11. All patients in the radiation and untreated groups had persistent tumor. Malignant behavior with death due to tumor was observed in five cases (four carotid body and one vagal body paraganglioma). Using modern techniques carotid body and vagal body paragangliomas can usually be managed by surgery alone. Other paragangliomas of the head and neck due to their anatomic location are sometimes best treated by a combination of surgery and radiation or only by radiation therapy.

Bilateral familial carotid body tumors: report of a patient with an occult contralateral tumor and postoperative hypertension

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