Succinate Dehydrogenase Complex Subunit D Research Articles

FRI368 Thyroid Paraganglioma: A Rare Manifestation Of Paraganglioma Syndrome Associated With SDHD Mutation

Abstract Disclosure: K. Samuel: None. C. McMullen: None. C. Veloski: None. S. Kushchayev: None. J.E. Hallanger-Johnson: None. J. Hernandez Prera: None. J. Muzaffar: None. G.Q. Yang: None. V. Tarasova: None. Background: Thyroid paragangliomas (TP) are exceptionally rare, representing 0.5% of all paragangliomas (PGL) with total of less than 70 cases reported to date. We report a case of a TP presenting with an indeterminate thyroid nodule, as a first manifestation of multifocal head and neck PGL, associated with succinate dehydrogenase complex subunit D (SDHD) mutation. Clinical case: A 59-year female was initially seen at the tertiary referral center for an indeterminate thyroid nodule discovered incidentally on neck ultrasound (US) ordered for evaluation of a palpable posterior left neck mass. Neck/thyroid US showed multiple nonspecific bilateral lymph nodes measuring up to 1.2 cm and a 1.7 cm right interpolar markedly hypoechoic and hypervascular solid thyroid nodule (TR5). Clinically, the patient did not have symptoms related to the thyroid nodules or lymph nodes in the neck. Thyroid function tests were within normal range. An US-guided FNA biopsy was nondiagnostic. Core biopsy was suspicious for papillary thyroid carcinoma (hypercellular thyroid parenchyma with some follicular cells with nuclear irregularity, grooves, and hyperchromasia). Pathology slides review at the tertiary center showed nondiagnostic sample (Bethesda I) on cytopathology and neuroendocrine neoplasm consistent with PGL on core biopsy (immunohistochemical stains showed tumor cells positive for synaptophysin, chromogranin and GATA3. TTF1, TG, calcitonin, CEA and AE1/3 negative). US of the neck/thyroid 4 months later showed stable disease. Calcitonin and 24-h urinary catecholamines, metanephrines were within normal limits. There was no family history of pheochromocytoma or PGL. Genetic testing showed germline SDHD mutation (p.P81L(c.242c>5). 68Ga-DOTATATE PET/CT revealed multifocal areas of increased somatostatin receptor expression from the skull base to the left thoracic inlet, which included right and left skull base lesions, left neck level IIA lymph node, right and left level III lymph nodes, right thyroid lobe lesion, and left prevascular superior mediastinal lesion. An MRI of the brain and neck with and without contrast showed 1.7 cm right jugular, 0.6 cm right carotid, and 0.6 cm left vagal PGL, 1.3 cm right thyroid nodule, left level II 1.1x.6 cm lymphadenopathy, and 0.4 cm left superior mediastinal nodule. A CT of the neck w/contrast showed multiple areas likely representing bilateral carotid body tumors, left vagal PGL, right glomus jugular, and thyroid PGL stable over 6 months. MIBG nuclear medicine scan revealed no radiotracer accumulation in the lesions. EBRT therapy is planned to the skull base lesion. Conclusions: TP should be considered in the differential diagnosis of hypervascular thyroid nodules in patients with SDH-related pheochromocytoma-PGL syndromes. This case illustrates the importance of experienced multidisciplinary team evaluation and management of complex and rare PRG cases. Presentation: Friday, June 16, 2023

Management of Multiple Head and Neck Paragangliomas With Assistance of a 3-D Model.

Extirpation of multiple head and neck paragangliomas carries challenge due to close anatomic relationships with critical neurovascular bundles. This study aims to assess whether the application of 3-D models can assist with surgical planning and treatment of these paragangliomas, decrease surgically related morbidity and mortality. Fourteen patients undergoing surgical resection of multiple head and neck paragangliomas were enrolled in this study. A preoperative 3-D model was created based on radiologic data, and relevant critical anatomic relationships were preoperatively assessed and intraoperatively validated. All 14 patients presented with multiple head and neck paragangliomas, including bilateral carotid body tumors (CBT, n = 9), concurrent CBT with glomus jugulare tumors (GJT, n = 4), and multiple vagal paragangliomas (n = 1). Ten patients underwent genomic analysis and all harbored succinate dehydrogenase complex subunit D (SDHD) mutations. Under guidance of the 3-D model, the internal carotid artery (ICA) was circumferentially encased by tumor on 5 of the operated sides, in 4 (80%) of which the tumor was successfully dissected out from the ICA, whereas ICA reconstruction was required on one side (20%). Following removal of CBT, anterior rerouting of the facial nerve was avoided in 3 (75%) of 4 patients during the extirpation of GJT with assistance of a 3-D model. Two patients developed permanent postoperative vocal cord paralysis. There was no vessel rupture or mortality in this study cohort. The 3-D model is beneficial for establishment of a preoperative strategy, as well as planning and guiding the intraoperative procedure for resection of multiple head and neck paragangliomas.

The emerging clinical relevance of genomic profiling in neuroendocrine tumours

BackgroundNeuroendocrine tumours (NETs) arise from hormone-producing or nervous system cells and can develop from anywhere in the body. They have heterogeneous origins from skin to gastrointestinal track and a complicated histology. Thus, there is an inevitable need for genomic profiling to determine the exact genetics of each tumour for prognosis and treatment strategies to overcome the disease’s complexity. For this purpose, next-generation-sequencing (NGS) is the most reliable methodology for both germ-line and somatic studies to make a clinical diagnosis. In this study, we analyse liquid biopsies, formalin fixed paraffin embedded (FFPE) tissues, and peripheral blood samples for their ability to provide information for actionability.MethodsA customized multi-gene panel comprised of Succinate Dehydrogenase Complex Iron Sulfur Subunit B (SDHB), Succinate Dehydrogenase Complex Subunit C (SDHC), Cell Division Cycle 73(CDC73), Calcium Sensing Receptor (CASR), Platelet Derived Growth Factor Receptor Alpha (PDGFRA), Succinate Dehydrogenase Complex Flavoprotein Subunit A (SDHA), Ret Proto-Oncogene (RET), Succinate Dehydrogenase Complex Assembly Factor 2(SDHAF2), Menin 1(MEN1), Succinate Dehydrogenase Complex Subunit D (SDHD), MYC Associated Factor X (MAX) and Protein Kinase CAMP-Dependent Type I Regulatory Subunit Alpha (PRKAR1A) genes was constructed to assess multiple specimen types including: 3 liquid biopsies, 6 FFPE tissues, and 26 peripheral blood samples from 35 unique NET patients. Quality-control and bioinformatics analyses were performed using QCI-Analyze and QCI-Interpret.ResultsThe three liquid biopsies and the 6 FFPE tissue samples were evaluated for somatic mutations; while the 26 peripheral blood samples were analysed using the germ-line pipeline. Five (55.6%) of the nine patients that were studied for somatic changes carried actionable mutations related to therapy sensitivities. Through the germ-line studies, we observed a 50% positivity rate for disease predisposition with 16 variants classified according to ACMG (American College of Medical Genetics) Standards and Guidelines.ConclusionsGenomic profiling medicine is an emerging area of clinical oncology and has become crucial for disease and patient management by providing a precision approach; this is especially true for rare diseases including rare cancers such as NETs. Notably, this study emphasized the relevance of multiple distinctive biological sample types for use in the genetic testing of cancers to help with the choice of therapy to maximize the likelihood of a positive clinical outcome.

Bcl2l10 induces metabolic alterations in ovarian cancer cells by regulating the TCA cycle enzymes SDHD and IDH1.

Bcl2-like-10 (Bcl2l10) has both oncogenic and tumor suppressor functions depending on the type of cancer. It has been previously demonstrated that the suppression of Bcl2l10 in ovarian cancer SKOV3 and A2780 cells causes cell cycle arrest and enhances cell proliferation, indicating that Bcl2l10 is a tumor suppressor gene in ovarian cancer cells. The aim of the present study was to identify possible downstream target genes and investigate the underlying mechanisms of action of Bcl2l10 in ovarian cancer cells. RNA sequencing (RNA-Seq) was performed to obtain a list of differentially expressed genes (DEGs) in Bcl2l10-suppressed SKOV3 and A2780 cells. The RNA-Seq data were validated by reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis, and the levels of metabolites after Bcl2l10-knockdown were measured using colorimetric assay kits. Pathway enrichment analysis revealed that the commonly downregulated genes in SKOV3 and A2780 cells after Bcl2l10-knockdown were significantly enriched in metabolic pathways. The analysis of the DEGs identified from RNA-Seq and validated by RT-qPCR revealed that succinate dehydrogenase complex subunit D (SDHD) and isocitrate dehydrogenase 1 (IDH1), which are key enzymes of the TCA cycle that regulate oncometabolite production, may be potential downstream targets of Bcl2l10. Furthermore, Bcl2l10-knockdown induced the accumulation of succinate and isocitrate through the downregulation of SDHD and IDH1. The present study was the first to elucidate the metabolic regulatory functions of Bcl2l10 in ovarian cancer cells, and the results indicated that Bcl2l10 may serve as a potential therapeutic target in ovarian cancer.

MON-249 SDHD Mutation: Nonfunctional Paragangliomas Presenting as Bilateral Carotid Body Tumors with Syncope

SDHD Mutation: Nonfunctional paragangliomas presenting as bilateral carotid body tumors with syncopeBackground:A mutation of the SDHD gene is associated with hereditary paraganglioma-pheochromocytoma (PGL/PCC) syndromes which most commonly originate in the head and neck region, and usually form in the carotid body. Paragangliomas (PGL) can be secretory or non-secretory with about 95% of head and neck PGL being non-secretory. They can rarely present with symptoms due to compression, however, as in this case of a 29 year-old female presenting with syncope.Clinical Case:A 29 year-old female presented for evaluation after syncope. She had a syncopal event and fell down while walking in her home. Syncope was preceded by about 15 minutes of flushing, nausea and palpitations. She reported similar episodes once weekly in the preceding months, which generally lasted an hour. Initial workup included normal vital signs at presentation, normal ECG and echocardiogram, normal TFT, CBC, complete metabolic panel. Subsequent head/neck CT revealed bilateral masses in the carotid bifurcations consistent with carotid body tumors. Further history revealed a family history of bilateral carotid body tumors in her father which had never been evaluated. Plasma and urine metanephrines were normal. She underwent carotid body tumor excision. The left carotid body tumor was successfully excised and pathology revealed a paraganglioma with positive synaptophysin and chromogranin stains. Genetic testing revealed an SDHD (succinate dehydrogenase complex subunit D) gene mutation. Repeat biochemical assessment 4 months later was again negative and patient remained asymptomatic postoperatively.Conclusion:Paragangliomas can be secretory or non-secretory with about 95% of head and neck paragangliomas being non-secretory, as in this case. Symptoms can arise from catecholamine hypersecretion, which generally presents as hypertension, headaches, diaphoresis, flushing, anxiety or palpitations, and can be episodic or sustained, or mass effect. Syncope as a presenting symptom is rare, however, and has not been quantified but only reported in case reports. The exact etiology of syncope in our patient is not clear. Hereditary PGL/PCC syndromes should be suspected in any individual with multiple, recurrent, early-onset (age less than 45 years) or family history of PGL/PCC, as these syndromes are inherited in an autosomal dominant manner.

Natural History and Management of Familial Paraganglioma Syndrome Type 1: Long-Term Data from a Large Family.

Head and neck paragangliomas are the most common clinical features of familial paraganglioma syndrome type 1 caused by succinate dehydrogenase complex subunit D (SDHD) mutation. The clinical management of this syndrome is still unclear. In this study we propose a diagnostic algorithm for SDHD mutation carriers based on our family case series and literature review. After genetic diagnosis, first evaluation should include biochemical examination and whole-body imaging. In case of lesion detection, nuclear medicine examination is required for staging and tumor characterization. The study summarizes the diagnostic accuracy of different functional imaging techniques in SDHD mutation carriers. 18F-3,4-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET)-computed tomography (CT) is considered the gold standard. If it is not available, 123I-Metaiodobenzylguanidine (MIBG) could be used also for predicting response to radiometabolic therapy. 18F-fluoro-2-deoxy-D-glucose (18F-FDG) PET-CT has a prognostic role since high uptake identifies more aggressive cases. Finally, 68Ga-peptides PET-CT is a promising diagnostic technique, demonstrating the best diagnostic accuracy in our and in other published case series, even if this finding still needs to be confirmed in larger studies. Periodic follow-up should consist of annual biochemical and ultrasonographic screening and biannual magnetic resonance examination to identify biochemical silent tumors early.

Germline SDHB and SDHD mutations in pheochromocytoma and paraganglioma patients.

Pheochromocytoma and paragangliomas (PCC/PGL) are neuroendocrine tumors that arise from chromaffin cells of the adrenal medulla and sympathetic/parasympathetic ganglia, respectively. Of clinical relevance regarding diagnosis is the highly variable presentation of symptoms in PCC/PGL patients. To date, the clear-cut correlations between the genotypes and phenotypes of PCC/PGL have not been entirely established. In this study, we reviewed the medical records of PCC/PGL patients with pertinent clinical, laboratory and genetic information. Next-generation sequencing (NGS) performed on patient samples revealed specific germline mutations in the SDHB (succinate dehydrogenase complex iron-sulfur subunit B) and SDHD (succinate dehydrogenase complex subunit D) genes and these mutations were validated by Sanger sequencing. Of the 119 patients, two were identified with SDHB mutation and one with SDHD mutation. Immunohistochemical (IHC) staining was used to analyze the expression of these mutated genes. The germline mutations identified in the SDH genes were c343C>T and c.541-542A>G in the SDHB gene and c.334-337delACTG in the SDHD gene. IHC staining of tumors from the c.343C>T and c.541-2A>G carriers showed positive expression of SDHB. Tumors from the c.334-337delACTG carrier showed no expression of SDHD and a weak diffused staining pattern for SDHB. We strongly recommend genetic testing for suspected PCC/PGL patients with a positive family history, early onset of age, erratic hypertension, recurrence or multiple tumor sites and loss of SDHB and/or SDHD expression. Tailored personal management should be conducted once a patient is confirmed as an SDHB and/or SDHD mutation carrier or diagnosed with PCC/PGL.

SDHD Gene Mutations: Looking Beyond Head and Neck Tumors

Objective: Succinate dehydrogenase complex, subunit D (SDHD) gene mutations are most commonly associated with head and neck paragangliomas. We describe a pair of cases with early-onset, bilateral pheochromocytoma (PCC) and paraganglioma (PGL) syndrome associated with SDHD mutation. Methods: We describe 2 cases of hereditary, early-onset, bilateral PCC/PGL syndrome associated with SDHD mutation. Results: Both cases presented under the age of 30 with bilateral PCC and PGL with SDHD mutations. Case 1 is a female who was initially diagnosed with hypertension and later work-up revealed elevated norepinephrine levels. Positron emission tomography coupled with computed tomography showed avid uptake of fluorodeoxyglucose by the right adrenal gland, the organ of Zuckerkandl, and the left carotid bifurcation. Surgical resection was performed and resulted in normalization of her catecholamines. Case 2 is a male who similarly presented with hypertension and elevated norepinephrine levels. Imaging revealed head, neck,...

Cowden syndrome-associated germline succinate dehydrogenase complex subunit D (SDHD) variants cause PTEN-mediated down-regulation of autophagy in thyroid cancer cells.

Thyroid cancer is a major component cancer of Cowden syndrome (CS), a disorder typically associated with germline mutations in PTEN. Germline variants in succinate dehydrogenase genes (SDHx) co-occurring with PTEN germline mutations confer a 2-fold increased prevalence (OR 2.7) of thyroid cancer compared to PTEN-associated CS but 50% decreased prevalence (OR 0.54) of thyroid cancer compared to SDHx-associated CS. We have previously shown that CS-associated SDHD variants G12S and H50R induce PTEN oxidation and nuclear accumulation in thyroid cancer. Our current study shows that SDHD-G12S and -H50R variants cause down-regulation of autophagy, demonstrating a role for SDHD in autophagy-associated pathogenesis of differentiated thyroid cancer. These findings could explain the increased prevalence of thyroid cancer in CS patients with SDHx germline mutations compared to those with PTEN mutations alone. Importantly, we demonstrate the dependence of this process on functional wild-type PTEN with reversal of decreased autophagy after PTEN knockdown. The latter could explain the clinically observed decrease in thyroid cancer prevalence in patients with co-existent PTEN mutations and SDHx variants. We also show that SDHD-G12S/H50R promotes mono-ubiquitination of PTEN, causing its translocation into the nucleus, upregulation of AKT and consequent phosphorylation of FOXO3a. Furthermore, SDHD-G12S/H50R-mediated increase in acetylation of FOXO3a further enhances AKT-associated phosphorylation of FOXO3a. This combination of phosphorylation and acetylation of FOXO3a results in its nuclear export for degradation and consequent down-regulation of FOXO3a-target autophagy-related gene (ATG) expression. Overall, our study reveals a novel mechanism of crosstalk amongst SDHD, PTEN and autophagy pathways and their potential roles in thyroid carcinogenesis.

Endocrine tumors associated with the vagus nerve.

The vagus nerve (cranial nerve X) is the main nerve of the parasympathetic division of the autonomic nervous system. Vagal paragangliomas (VPGLs) are a prime example of an endocrine tumor associated with the vagus nerve. This rare, neural crest tumor constitutes the second most common site of hereditary head and neck paragangliomas (HNPGLs), most often in relation to mutations in the succinate dehydrogenase complex subunit D (SDHD) gene. The treatment paradigm for VPGL has progressively shifted from surgery to abstention or therapeutic radiation with curative-like outcomes. Parathyroid tissue and parathyroid adenoma can also be found in close association with the vagus nerve in intra or paravagal situations. Vagal parathyroid adenoma can be identified with preoperative imaging or suspected intraoperatively by experienced surgeons. Vagal parathyroid adenomas located in the neck or superior mediastinum can be removed via initial cervicotomy, while those located in the aortopulmonary window require a thoracic approach. This review particularly emphasizes the embryology, molecular genetics, and modern imaging of these tumors.

Carotid Body Paraganglioma With an SDHD Gene Mutation: The Need For Genetic Testing

ABSTRACT Objective: To report a case of carotid body paraganglioma occurring in conjunction with a succinate dehydrogenase complex subunit D (SDHD) gene mutation with comorbidities of multiple retroperitoneal paragangliomas and pheochromocytoma. This case emphasizes the importance of performing genetic analyses in all cases of paragangliomas with carotid body involvement, multifocal origin, or concurrent pheochromocytoma to identify potential hereditary tumor susceptibility. We also emphasize the importance of familial screening of all first-degree family relatives of patients who test positive for germline mutations. Methods: A 30-year-old male underwent surgery to excise a carotid body tumor and multiple retroperitoneal masses and to perform a partial adrenalectomy. Results: Pathologic evaluation of carotid body and retroperitoneal specimens confirmed that they were histologically and immunohistochemically consistent with paragangliomas. The excised adrenal gland specimen tested positive for pheochromoc...

Disomy as the Genetic Underlying Mechanisms of Loss of Heterozigosity in SDHD-Paragangliomas

Succinate dehydrogenase complex, subunit D (SDHD) mutations cause pheochromocytoma/paraganglioma syndrome. SDHD, located at chromosome 11q23, shows a parent-of-origin effect because the disease is observed almost exclusively when the mutation is transmitted from the father, although some cases of maternal transmission have been reported. Several hypotheses have been proposed for this peculiar inheritance pattern, but the underlying mechanisms have not yet been clearly elucidated. The objective of the study was to explain the parent-of-origin effect in a family, mainly affected by paternally transmitted paragangliomas, and with a maternally transmitted renal tumor. Peripheral blood DNA from 15 carriers and 7 tumor DNA samples from SDHD-p.Trp5* carriers were studied. We conducted mutation genotyping and microsatellite marker analysis in germline and tumor DNA and methylation status analysis in tumor DNA by methylation-specific multiplex ligation-dependent probe amplification. Mutation genotyping and microsatellite marker analysis demonstrated loss of heterozygosity of the wild-type allele (maternal) in all studied tumors, except the renal tumor, which lost the mutated allele (maternal), and the prostate tumor, which had no loss of heterozygosity. The methylation-specific multiplex ligation-dependent probe amplification demonstrated that the methylation profile corresponded exclusively to the paternal chromosome without genomic loss, suggesting paternal uniparental disomy as the mechanism underlying the parent-of-origin effect in this SDHD family. The paternal uniparental disomy involves the loss of maternally imprinted cell cycle regulators and the overexpression of paternally imprinted growth activators, leading to tumorigenesis in this syndrome.

A spontaneous paraganglioma-pheochromocytoma syndrome.

We present a case of a 40–year old woman diagnosed with a four–place spontaneous paraganglioma–pheochromocytoma syndrome, which was treated surgically. The presence of the succinate dehydrogenase complex subunit D (SDHD) mutation that causes the pheochromocytoma was confirmed but no mutations in the family members were found. After the excision of the paragangliomas located in the areas of the division of carotid arteries, and mediastinum, as well as a tumor on the left site of the celiac trunk, the patient remains asymptomatic and is regularly followed–up.

Cloning, mapping and association study with carcass traits of the porcine SDHD gene

A 1320-bp cDNA containing the full coding region of the porcine succinate dehydrogenase complex, subunit D (SDHD) gene was obtained by random sequencing of clones from a Chinese Tongcheng pig 55-day fetal longissimus dorsi muscle cDNA library. Analysis of the SDHD gene across the INRA-University of Minnesota porcine radiation hybrid panel indicated close linkage with microsatellite marker SW2401, located on SSC9p21. The open reading frame of this cDNA covers 480 bp and encodes 159 amino acids. The deduced porcine amino acid sequence showed greater similarity with human and bovine protein sequences than with those from mouse and rat. The BLAST analysis of the porcine SDHD to NCBI identified Unigene Cluster Ssc.2586. Possible single nucleotide polymorphisms (SNP) were identified by alignment of expressed sequence tags in the cluster. The polymerase chain reaction (PCR) single strand conformation polymorphism, sequencing, and PCR restriction fragment length polymorphism were used to confirm and detect a synonymous polymorphic MboI site within the open-reading frame. Allele frequencies of this SNP were investigated in two commercial and five Chinese local pig breeds. These five Chinese breeds had very high frequencies for one allele, whereas frequencies of both alleles were intermediate in Large White and Duroc. An association analysis suggested that different SDHD genotypes have significant differences in loin-muscle area (P < 0.01).

Identification of novel SDHD mutations in patients with phaeochromocytoma and/or paraganglioma.

Familial paraganglioma is a dominantly inherited disorder characterised by the development of highly vascular tumours in the head and neck. Recently, a relationship between hereditary tumours derived from the autonomic nervous system and germline mutations in the gene encoding succinate dehydrogenase complex subunit D (SDHD) is increasingly a subject of study. Familial paraganglioma syndrome is embryologically related to phaeochromocytoma, another neuroendocrine tumour that shows great aetiological and genetic heterogeneity. Some hereditary phaeochromocytomas may be associated with germline mutations in VHL, RET and NF1 genes in genetic disorders such as von Hippel-Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN 2) and neurofibromatosis type 1 (NF 1), respectively. However, there are many cases that cannot be explained by mutations in these genes. In this report, we describe two previously unreported mutations in two patients from 25 unrelated kindreds with phaeochromocytoma and/or paraganglioma disorders and with or without familial antecedents: a mutation featuring the change of tryptophan to a termination codon in exon 2, and a 4-bp deletion in exon 4 that results in a truncated protein. We also describe one missense substitution of uncertain significance. The patients had previously tested negative for germline mutations in VHL and RET genes and had not been previously selected. The involvement of SDHD mutations in familial phaeochromocytoma and/or paraganglioma predisposition is of considerable interest since other studies have shown these alterations to be associated with highly expressed angiogenic factors.

Germline SDHD mutation in familial phaeochromocytoma

The genetic basis for familial phaeochromocytoma is unknown in many cases. Since the disorder has been reported in some cases of familial head and neck paraganglioma, which is caused by a mutation in the gene encoding succinate dehydrogenase complex subunit D (SDHD), we investigated this gene in kindreds with familial phaeochromocytoma. A germline SDHD frameshift mutation was identified in a two-generation family consisting of four children with phaeochromocytoma, but somatic mutations were not detected in 24 sporadic phaeochromocytoma tumours. Germline SDHD mutation analysis should be done in individuals with familial, multiple, or early-onset phaeochromocytomas even if a personal or family history of head and neck paraganglioma is absent.