Pathogenic Mutations Research Articles

Myopathy in glycogen storage disease type IV: case report of a family

Aim. To study the clinical presentation and differential diagnosis of a rare hereditary disease glycogen storage disease type IV with progressive skeletal myopathy in a case report of a family.Materials and methods. Two patients were followed up in the specialized neurology unit of the regional clinical hospital and in the outpatient setting.Results. Long-term follow-up and examination in two clinically similar cases of myopathy in siblings allowed us to diagnose a hereditary metabolic disease. The congenital muscular form of glycogen storage disease type IV was manifested by myopathy and peripheral tetraparesis with the development of bone deformities. Difficulty in the diagnosis was due to isolated myopathy progression with no signs of liver involvement. The diagnosis was established with account of clinical manifestations, the progressive course of the disease, electromyography findings, and the results of molecular genetic testing for pathogenic mutations associated with hereditary neuromuscular diseases.Conclusion. Glycogen storage disease type IV can clinically manifest itself by progressive myopathy without liver involvement and changes in blood biochemistry. The presented clinical cases in siblings are identical. Myopathy does not have clinical features that are significant for the differential diagnosis with other hereditary neuromuscular diseases. Genetic testing identified a mutation in the GBE1 gene and is considered as the main diagnostic criterion of the disease.

Anakinra-Dependent Recurrent Pericarditis: The Role of the R202Q Variant of the MEFV Gene.

Background: the role of the R202Q (c.605G>A, p.Arg202Gln) missense variant of the MEFV gene has been debated as either a benign polymorphism or a potentially pathogenic mutation. We report and discuss here the case of a young female with corticosteroid-dependent recurrent pericarditis carrying the homozygous R202Q variant, exhibiting distinctive clinical features possibly influenced by this genetic variant. Methods: a 30-year-old woman with a previous diagnosis of cancer and recent respiratory infection presented with severe pleuritic chest pain, hypotension, tachycardia, and fever. Initial diagnostic evaluation indicated cardiac tamponade, and emergent pericardiocentesis was performed. Despite initial treatment with NSAIDs, colchicine, and corticosteroids, the patient experienced multiple recurrences. Genetic testing identified homozygous R202Q variant in the MEFV gene. Given the corticosteroid dependency and recurrent nature of her condition, IL-1 inhibitor anakinra was introduced, leading to significant improvement, although tapering below 150 mg per week failed to prevent recurrences. Results: the introduction of anakinra resulted in rapid symptom relief and resolution of pericardial effusion. However, attempts to taper or discontinue anakinra led to pericarditis recurrences. Ultimately, a maintenance dose of 50 mg every three days was established, which maintained remission for 18 months without recurrence. Despite multiple tapering attempts, further reduction in anakinra dosage was unsuccessful without triggering relapses. Conclusions: the R202Q variant, although typically considered benign, may contribute to an autoinflammatory phenotype resembling familial Mediterranean fever. This case underscores the potential pathogenicity of the homozygous R202Q variant in recurrent pericarditis and its responsiveness to IL-1 inhibition. In patients with corticosteroid-dependent recurrent pericarditis, genetic testing for the R202Q variant should be considered when anti-IL-1 drugs cannot be withdrawn. Further studies are warranted to elucidate the variant's role in pericardial inflammation and guide personalized treatment strategies.

The pathogenic germline ETV4 P433L mutation identified in multiple primary lung cancer affect tumor stem-like property by Wnt/β-catenin pathway

The occurrence of multiple primary lung cancer (MPLC) has witnessed a significant surge in recent years within the Chinese population. MPLC is distinguished by its potential genetic susceptibility and notable genetic heterogeneity. Investigating the etiology of MPLC holds substantial clinical importance.The whole genome sequencing (WGS) and genome-wide linkage analysis were performed in a family affected by a dominant form of lung abnormalities. Specifically, five family members were diagnosed with MPLC, while nine members had pulmonary nodules and one normal member. To confirm the potential pathogenic germline mutations sites, Sanger sequencing was performed in an additional 162 MPLC family patients. Furthermore, molecular biology experiments were conducted to investigate the function and the mechanism of the identified pathogenic mutation site in lung cancer A549 and H322, both in vitro and in vivo. Linkage analysis revealed the presence of shared genomic regions among affected family members. Subsequent exome sequencing identified a deleterious variant within these linkage intervals, specifically a heterozygous mutation in ETS-oncogene transcription factors 4 (ETV4). This particular variant was found in affected family members at a rate of 13 out of 15 individuals. Furthermore, ETV4 P433L mutation could be detected in an additional MPLC family patients and mutation frequency was 3.7% (6 out of 162). The ETV4 P433L mutations site was introduced into lung cancer cell lines, resulting in altered migration and stem-like properties of the cancer cells. Further investigation revealed that the activation of the Wnt/β-catenin signaling pathway, which is associated with stemness, could be attributed to the presence of the ETV4 P433L mutation, suggesting its involvement in tumor promotion. A novel pathogenic germline mutation, ETV4 P433L, was identified in a dominant MPLC family, with a mutation rate of 3.7% among MPLC family patients. The ETV4 P433L mutation was found to impact the stem-like properties and migration of tumors through Wnt/β-catenin signaling pathway.

Infrared spectroscopy as a new approach for early fabry disease screening: a pilot study

BackgroundFabry disease (FD) is a rare X-linked lysosomal storage disorder marked by alpha-galactosidase-A (α-Gal A) deficiency, caused by pathogenic mutations in the GLA gene, resulting in the accumulation of glycosphingolipids within lysosomes. The current screening test relies on measuring α-Gal A activity. However, this approach is limited to males. Infrared (IR) spectroscopy is a technique that can generate fingerprint spectra of a biofluid’s molecular composition and has been successfully applied to screen numerous diseases. Herein, we investigate the discriminating vibration profile of plasma chemical bonds in patients with FD using attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy.ResultsThe Fabry disease group (n = 47) and the healthy control group (n = 52) recruited were age-matched (39.2 ± 16.9 and 36.7 ± 10.9 years, respectively), and females were predominant in both groups (59.6% and 65.4%, respectively). All patients had the classic phenotype (100%), and no late-onset phenotype was detected. A generated partial least squares discriminant analysis (PLS-DA) classification model, independent of gender, allowed differentiation of samples from FD vs. control groups, reaching 100% sensitivity, specificity and accuracy.ConclusionATR-FTIR spectroscopy harnessed to pattern recognition algorithms can distinguish between FD patients and healthy control participants, offering the potential of a fast and inexpensive screening test.

A pathogenic mutation in the ALS/FTD gene VCP induces mitochondrial hypermetabolism by modulating the permeability transition pore

Valosin-containing protein (VCP) is a ubiquitously expressed type II AAA+ ATPase protein, implicated in both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This study aimed to explore the impact of the disease-causing VCPR191Q/wt mutation on mitochondrial function using a CRISPR/Cas9-engineered neuroblastoma cell line. Mitochondria in these cells are enlarged, with a depolarized mitochondrial membrane potential associated with increased respiration and electron transport chain activity. Our results indicate that mitochondrial hypermetabolism could be caused, at least partially, by increased calcium-induced opening of the permeability transition pore (mPTP), leading to mild mitochondrial uncoupling. In conclusion, our findings reveal a central role of the ALS/FTD gene VCP in maintaining mitochondrial homeostasis and suggest a model of pathogenesis based on progressive alterations in mPTP physiology and mitochondrial energetics.

Loss of mitochondrial Ca2+ response and CaMKII/ERK activation by LRRK2R1441G mutation correlate with impaired depolarization-induced mitophagy

BackgroundStress-induced activation of ERK/Drp1 serves as a checkpoint in the segregation of damaged mitochondria for autophagic clearance (mitophagy). Elevated cytosolic calcium (Ca2+) activates ERK, which is pivotal to mitophagy initiation. This process is altered in Parkinson’s disease (PD) with mutations in leucine-rich repeat kinase 2 (LRRK2), potentially contributing to mitochondrial dysfunction. Pathogenic LRRK2 mutation is linked to dysregulated cellular Ca2+ signaling but the mechanism involved remains unclear.MethodsMitochondrial damages lead to membrane depolarization. To investigate how LRRK2 mutation impairs cellular response to mitochondrial damages, mitochondrial depolarization was induced by artificial uncoupler (FCCP) in wild-type (WT) and LRRK2R1441G mutant knockin (KI) mouse embryonic fibroblasts (MEFs). The resultant cytosolic Ca2+ flux was assessed using live-cell Ca2+ imaging. The role of mitochondria in FCCP-induced cytosolic Ca2+ surge was confirmed by co-treatment with the mitochondrial sodium-calcium exchanger (NCLX) inhibitor. Cellular mitochondrial quality and function were evaluated by Seahorse™ real-time cell metabolic analysis, flow cytometry, and confocal imaging. Mitochondrial morphology was visualized using transmission electron microscopy (TEM). Activation (phosphorylation) of stress response pathways were assessed by immunoblotting.ResultsAcute mitochondrial depolarization induced by FCCP resulted in an immediate cytosolic Ca2+ surge in WT MEFs, mediated predominantly via mitochondrial NCLX. However, such cytosolic Ca2+ response was abolished in LRRK2 KI MEFs. This loss of response in KI was associated with impaired activation of Ca2+/calmodulin-dependent kinase II (CaMKII) and MEK, the two upstream kinases of ERK. Treatment of LRRK2 inhibitor did not rescue this phenotype indicating that it was not caused by mutant LRRK2 kinase hyperactivity. KI MEFs exhibited swollen mitochondria with distorted cristae, depolarized mitochondrial membrane potential, and reduced mitochondrial Ca2+ store and mitochondrial calcium uniporter (MCU) expression. These mutant cells also exhibited lower cellular ATP: ADP ratio albeit higher basal respiration than WT, indicating compensation for mitochondrial dysfunction. These defects may hinder cellular stress response and signals to Drp1-mediated mitophagy, as evident by impaired mitochondrial clearance in the mutant.ConclusionsPathogenic LRRK2R1441G mutation abolished mitochondrial depolarization-induced Ca2+ response and impaired the basal mitochondrial clearance. Inherent defects from LRRK2 mutation have weakened the cellular ability to scavenge damaged mitochondria, which may further aggravate mitochondrial dysfunction and neurodegeneration in PD.

Effect of Pathogenic Mutations on the Formation of High-Order Dynamin 2 Assemblies in Living Cells.

Mutations in dynamin 2 (DNM2) have been associated with two distinct movement disorders: Charcot-Marie-Tooth neuropathies (CMT) and centronuclear myopathy (CNM). Most of these mutations are clustered in the pleckstrin homology domain (PHD), which engages in intramolecular interactions that limit dynamin self-assembly and GTPase activation. CNM mutations interfere with these intramolecular interactions and suppress the formation of the autoinhibited state. CMT mutations are located primarily on the opposite surface of the PHD, which is specialized for phosphoinositide binding. It has been speculated that the distinct locations and interactions of residues mutated in CMT and CNM explain why each set of mutations causes either one disease or the other, despite their close proximity within the PHD sequence. We previously reported that at least one CMT-causing mutant, lacking residues 555DEE557 (ΔDEE), displays the same inability to undergo autoinhibition as observed in CNM-linked mutants. Here, we show that both the DNM2ΔDEE and CNM-linked DNM2A618T mutants form larger and more stable structures on the plasma membrane than that of wild-type DNM2 (DNM2WT). However, DNM2A618T forms cytoplasmic inclusions at concentrations lower than those of either DNM2WT or DNM2ΔDEE, suggesting that CNM-linked mutations confer more severe gain-of-function properties than the ΔDEE mutation.

Analyzing the Mutational Landscape of Prostate Cancer Susceptibility Genes through Next-Generation Sequencing (NGS) Analysis

Prostate cancer, a significant public health concern, exhibits a complex genetic landscape influenced by a variety of susceptibility genes. This study deciphers the intricate genetic makeup of prostate cancer by examining mutations in 14 prostate cancer susceptibility genes. The Next-Generation Sequencing (NGS) approach was employed on a cohort of 45 prostate cancer patients to detect mutations. The gnomAD database was used to analyze mutational frequencies in the Asian population suffering from prostate cancer. The cBioPortal database was employed to check the presence of observed mutations in The Cancer Genome Atlas (TCGA) dataset. In addition, this study employed RT-qPCR and Immunohistochemistry (IHC) techniques were utilized to check the functional consequences of the observed pathogenic mutations. Finally, Metascape and DrugBank resources were used for gene enrichment and drug prediction analyses. Results of the NGS analysis revealed a total of 29 mutations (pathogenic and benign) within the examined prostate cancer cohort, distributed across four key genes (BRCA1/2, TP53, and PMS2) out of the total analyzed 14 genes. Pathogenic mutations in BRCA1/2 and TP53 genes are of particular interest due to their fundamental roles in DNA repair, cell cycle regulation, and tumor suppression. Functional consequence analyses (RT-qPCR and IHC) demonstrated the down-regulation of BRCA1/2 and TP53 genes in prostate cancer samples with pathogenic mutations, reinforcing the disruption of their tumor suppressor roles. Lastly, drug prediction analysis uncovered promising therapeutic options by identifying drugs capable of enhancing the mRNA expression of these genes. This opens new avenues for tailored treatment strategies aimed at restoring normal cellular functions of the BRCA1/2 and TP53 genes. In conclusion, this study provides a comprehensive view of genetic mutations in prostate cancer susceptibility genes, ranging from benign to pathogenic. It emphasizes the genetic complexity of prostate cancer and offers insights into potential mechanisms driving this malignancy. These findings lay the groundwork for further research, personalized treatment approaches, and enhanced clinical management of prostate cancer.

Uncovering novel pathogenic variants and pathway mutations in triple-negative breast cancer among the endogamous mizo tribe.

The incidence of triple-negative breast cancer (TNBC) in India is higher compared to Western populations. The objective of this study is to identify novel and less reported variants in TNBC in Mizoram, a state with a high cancer incidence in India. We analysed whole exome sequencing data from triple-negative breast cancer (TNBC) patients in the Mizo population to identify key and novel variants. Moreover, we analysed reported breast cancer-related genes and pathway alterations. Somatic mutation analysis revealed that TP53 was the most frequently mutated gene and TP53, CACNA1E, IGSF3, RYR1, and FAM155A as significantly mutated driver genes. Based on the ACMG guidelines, we identified a rare pathogenic germline variant of BRCA1 (p.C1697R) in 13% and a likely pathogenic frameshift insertion in RBMX (p.P106Ffs) in 73% of the patients. We also found that the ATM, STK11, and CDKN2A genes were significantly mutated in germline TNBC samples compared to healthy samples. Moreover, we identified novel somatic variants in CHEK2 (p.K182M) and NF1 (p.C245X), and novel germline variants RB1 (p.D111G), CDH1 (p.A10Gfs), CDKN2A (p.V96G), CDKN2A (p.S12Afs*22), MAP3K1 (CAAdelins0), MSH6 (p.L1226_L1230del), and PMS2 (TTCdelins0). Pathway analysis revealed that most somatic mutations were highly associated with PI3K-Akt signalling pathway and MAPK signalling pathways in TNBC. These findings identified novel variants and key genes contributing to disease development and progression. Further analysis of less studied genes, including RBMX, MRC1, ATM, CTNNB1, and CDKN2A, in TNBC may reveal new potential genes for targeted therapeutic strategies and contribute to clinical advancements in the treatment of TNBC.

Taurine hypomodification underlies mitochondrial tRNATrp-related genetic diseases.

Escherichia coli MnmE and MnmG form a complex (EcMnmEG), generating transfer RNA (tRNA) 5-carboxymethylaminomethyluridine (cmnm5U) modification. Both cmnm5U and equivalent 5-taurinomethyluridine (τm5U, catalyzed by homologous GTPBP3 and MTO1) are found at U34 in several human mitochondrial tRNAs (hmtRNAs). Certain mitochondrial DNA (mtDNA) mutations, including m.3243A>G in tRNALeu(UUR) and m.8344A>G in tRNALys, cause genetic diseases, partially due to τm5U hypomodification. However, whether other mtDNA variants in different tRNAs cause a defect in τm5U biogenesis remains unknown. Here, we purified naturally assembled EcMnmEG from E. coli. Notably, EcMnmEG was able to incorporate both cmnm5U and τm5U into hmtRNATrp (encoded by MT-TW), providing a valuable basis for directly monitoring the effects of mtDNA mutations on U34 modification. In vitro, several clinical hmtRNATrp pathogenic mutations caused U34 hypomodification. A patient harboring an m.5541C>T mutation exhibited hmtRNATrp τm5U hypomodification. Moreover, using mtDNA base editing, we constructed two cell lines carrying m.5532G>A or m.5545C>T mutations, both of which exhibited hmtRNATrp τm5U hypomodification. Taurine supplementation improved mitochondrial translation in patient cells. Our findings describe the third hmtRNA species with mutation-related τm5U-hypomodification and provide new insights into the pathogenesis and intervention strategy for hmtRNATrp-related genetic diseases.

COSMIC Database and Structural Modeling Analysis of CYP2D6 Mutations in Human Cancers.

Single nucleotide polymorphisms (SNPs) in cytochrome P450 (CYP450) enzymes alter the metabolism of a variety of drugs. Numerous medications, including chemotherapies, are metabolized by CYP450 enzymes, making the expression of this suite of enzymes in tumor cells relevant to prescription regimens for cancer patients. We analyzed the characteristics of mutations of the CYP2D6 enzymes in cancer patients obtained from the Catalogue of Somatic Mutations in Cancer (COSMIC), including mutation type, age of the patient, tissue type, and histology. Mutations were analyzed through the Cancer-Related Analysis of Variants Toolkit (CRAVAT) software along with CHASM and VEST4 algorithms to determine the likelihood of being a driver and/or pathogenic mutation. For mutations with significant CHASM and VEST4 scores, structural analysis of each corresponding mutant protein was performed. The effect of each mutation was evaluated for its impact on the overall protein stability and ligand binding using Foldit Standalone and SwissDock, respectively. Structural analysis revealed that several missense mutations in CYP2D6 resulted in altered stability after energy minimization. Three missense mutations of CYP2D6 significantly altered docking stability and those located on alpha-helices near the docking site had a more significant impact than those not found in secondary protein structures. In conclusion, we have identified a series of mutations to CYP2D6 enzymes with possible relevance to cancer pathologies. Significance Statement CYP2D6 is responsible for the metabolism of many anti-cancer drugs. This study identified and characterized a series of mutations in the CYP2D6 enzyme that occurred in tumors. We found it likely that many of these mutations would alter enzyme function, leading to changes in drug metabolism in the tumor. We provide a basis for predicting the likelihood of a patient carrying these mutations to identify patients who may benefit from a precision medicine approach to drug selection and dosing.

Development and Assessment of a Point-of-Care Application (Genomic Medicine Guidance) for Heritable Thoracic Aortic Disease.

Genetic testing can determine familial and personal risks for heritable thoracic aortic aneurysms and dissections (TAD). The 2022 American College of Cardiology/American Heart Association guidelines for TAD recommend management decisions based on the specific gene mutation. However, many clinicians lack sufficient comfort or insight to integrate genetic information into clinical practice. We therefore developed the Genomic Medicine Guidance (GMG) application, an interactive point-of-care tool to inform clinicians and patients about TAD diagnosis, treatment, and surveillance. GMG is a REDCap-based application that combines publicly available genetic data and clinical recommendations based on the TAD guidelines into one translational education tool. TAD genetic information in GMG was sourced from the Montalcino Aortic Consortium, a worldwide collaboration of TAD centers of excellence, and the National Institutes of Health genetic repositories ClinVar and ClinGen. The application streamlines data on the 13 most frequently mutated TAD genes with 2286 unique pathogenic mutations that cause TAD so that users receive comprehensive recommendations for diagnostic testing, imaging, surveillance, medical therapy, and preventative surgical repair, as well as guidance for exercise safety and management during pregnancy. The application output can be displayed in a clinician view or exported as an informative pamphlet in a patient-friendly format. The overall goal of the GMG application is to make genomic medicine more accessible to clinicians and patients while serving as a unifying platform for research. We anticipate that these features will be catalysts for collaborative projects aiming to understand the spectrum of genetic variants contributing to TAD.

Nodule-specific NRF2-targeted upregulation in patients with KEAP1 mutations and familial nontoxic multinodular goiter.

Kelch-like ECH-associated protein 1 (KEAP1) is associated with nuclear factor erythroid-2 related factor 2 (NRF2) and promotes NRF2 degradation in normal conditions. Genetic abnormality in KEAP1 is a rare disease and presents with familial multinodular goiter. This study assessed the clinical and molecular findings concerning nodular formation in the thyroid gland of patients harboring KEAP1 germline mutations. Next-generation sequencing analysis targeting goiter-associated genes was performed on 39 patients with familial multinodular goiter. The expression of NRF2-targeted genes from surgical thyroid specimens of patients with KEAP1 mutations were analyzed using a whole transcript expression array and immunohistochemistry. We found five probands with pathogenic heterozygous mutations in KEAP1 (p.Q86*, p.L136P, p.V411fs, p.R415C, and p.R483H), which had no meaningful concomitance with mutations of other goiter-associated genes in germline and somatic levels. Their common histopathological features showed multinodular goiters in the entire thyroid gland with few degenerative lesions or complications of malignancy and slow proliferation indicating < 1% at the Ki-67 labeling index. Among 42 NRF2-targeted genes, antioxidant genes were most frequently upregulated (11/12) in the nodule, followed by detoxification genes (6/11). Immunohistochemical analysis showed relatively high expression of glutathione peroxidase 2 and NAD(P)H quinone oxidoreductase 1 (representative NRF2-targeted genes) in the nodules of various patients harboring KEAP1 mutations. KEAP1 germline heterozygous mutations exert excessive NRF2 activity in the thyroid gland and may confer cytoprotective effects even under abundant reactive oxygen species associated with thyroid hormone production, resulting in thyroid hyperplasia with scarce degradation.

Identification of Pathogenic Missense Mutations of NF1 Using Computational Approaches

Neurofibromatosis type 1 (NF1) is a prevalent autosomal dominant disorder caused by mutations in the NF1 gene, leading to multisystem disorders. Given the critical role of cysteine residues in protein stability and function, we aimed to identify key NF1 mutations affecting cysteine residues that significantly contribute to neurofibromatosis pathology. To identify the most critical mutations in the NF1 gene that contribute to the pathology of neurofibromatosis, we employed a sophisticated computational pipeline specifically designed to detect significant mutations affecting the NF1 gene. Our approach involved an exhaustive search of databases such as the Human Gene Mutation Database (HGMD), UniProt, and ClinVar for information on missense mutations associated with NF1. Our search yielded a total of 204 unique cysteine missense mutations. We then employed in silico prediction tools, including PredictSNP, iStable, and Align GVGD, to assess the impact of these mutations. Among the mutations, C379R, R1000C, and C1016Y stood out due to their deleterious effects on the biophysical properties of the neurofibromin protein, significantly destabilizing its structure. These mutations were subjected to further phenotyping analysis using SNPeffect 4.0, which predicted disturbances in the protein’s chaperone binding sites and overall structural stability. Furthermore, to directly visualize the impact of these mutations on protein structure, we utilized AlphaFold3 to simulate both the wild-type and mutant NF1 structures, revealing the significant effects of the R1000C mutation on the protein’s conformation. In conclusion, the identification of these mutations can play a pivotal role in advancing the field of precision medicine and aid in the development of effective drugs for associated diseases.

Mapping multimodal phenotypes to perturbations in cells and tissue with CRISPRmap.

Unlike sequencing-based methods, which require cell lysis, optical pooled genetic screens enable investigation of spatial phenotypes, including cell morphology, protein subcellular localization, cell-cell interactions and tissue organization, in response to targeted CRISPR perturbations. Here we report a multimodal optical pooled CRISPR screening method, which we call CRISPRmap. CRISPRmap combines in situ CRISPR guide-identifying barcode readout with multiplexed immunofluorescence and RNA detection. Barcodes are detected and read out through combinatorial hybridization of DNA oligos, enhancing barcode detection efficiency. CRISPRmap enables in situ barcode readout in cell types and contexts that were elusive to conventional optical pooled screening, including cultured primary cells, embryonic stem cells, induced pluripotent stem cells, derived neurons and in vivo cells in a tissue context. We conducted a screen in a breast cancer cell line of the effects of DNA damage repair gene variants on cellular responses to commonly used cancer therapies, and we show that optical phenotyping pinpoints likely pathogenic patient-derived mutations that were previously classified as variants of unknown clinical significance.

Identification of novel variants in hereditary spherocytosis patients by whole-exome sequencing

Defects in erythrocyte membrane proteins can cause the most common type of inherited hemolytic anemia, so called hereditary spherocytosis (HS). It is characterized by the appearance of spherocytes in peripheral blood, hemolytic anemia, splenomegaly, jaundice and gallstones. Due to difficulty of diagnosis solely based on aforementioned parameters, the addition of genetic testing seems to be effective and most acknowledged. Up to date, pathogenic variations in five genes encoding membrane proteins (ANK1, SPTA1, SPTB, SLC4A1, EPB42) are identified to cause HS. Here, we have studied the genetic spectrum in forty-one patients with clinically suspected HS and their families, as well as their genotype-phenotype correlations. Pathogenic mutations in ANK1, SPTB, SLC4A1 and SPTA1 were found in 17 (41.5 %), 12 (29.3 %), 7 (17.1 %) and 5 (12.2 %) patients, respectively. Deleterious variants include 12 missense, 15 nonsense, 12 frameshift, and 4 splicing variants. Among these variations 32 were novel. In our genotype-phenotype analysis, platelet levels in SPTB (p = 0.021) and SLC4A1 (p = 0.02) patients were found to be significantly lower than ANK1 patients. In addition, LDH levels in SPTB patients were remarkably lower than patients with ANK1 mutations (p = 0.025).

7768 Hereditary Phaeochromocytoma/Paraganglioma And Aortopathy In A Patient With Known Macroprolactinoma: A Series Of Incidental Findings

Abstract Disclosure: J.R. Kelly: None. S. Soule: None. P.J. Hunt: None. Background: The three P association (3PAs) describes the combination of pituitary adenoma and phaeochromocytoma/paraganglioma. Recent case series describe a range of underlying genetic causes, including SDH mutations. We describe a patient with a macroprolactinoma and their subsequent incidental diagnoses of phaeochromocytoma and paraganglioma, with a pathogenic SDHA mutation. Clinical Case: A 58-year-old man had previously received a combination of medical therapy with cabergoline and transsphenoidal debulking surgery for a histologically confirmed macroprolactinoma. Due to a small risk of valvulopathy associated with cumulative doses of cabergoline, screening echocardiogram was requested after seven years of treatment. This showed a calcified bicuspid aortic valve and severe dilatation of the ascending aorta at 58mm. Prior to surgical repair, CT aorta was requested, which showed an incidental left adrenal lesion. Formal adrenal imaging and functional assessment confirmed a 50mm phaeochromocytoma, with a right para-aortic paraganglioma subsequently revealed on Ga-68 DOTATATE-PET scan. He described symptoms of catecholamine excess, with episodic palpitations, chest pain, and increasing anxiety over the previous year, on a background of hypertension. Hereditary phaeochromocytoma/paraganglioma gene panel revealed a pathogenic mutation in SDHA (c.1663+1G&amp;gt;T) – a splicing variant, likely resulting in nonsense decay. Screening was recommended for his three children. He initiated alpha blockade with doxazosin, then beta blockade with metoprolol, prior to open adrenalectomy and excision of paraganglioma. Histology confirmed a left phaeochromocytoma (Ki67 0.1%, PASS score 8, no vascular or capsular invasion) and a paraganglioma. Post-operative plasma normetanephrine normalised (406 pmol/L, pre-operative 6776 pmol/L, normal &amp;lt;1200 pmol/L) and the patient described resolution of symptoms. He subsequently underwent tissue aortic valve replacement and Bentall’s procedure. Histology showed severe atherosclerosis with diffuse medial degeneration of the aorta. Repeat Ga-68 DOTATATE-PET seven months later showed no evidence of residual or recurrent disease. Ongoing management includes cabergoline, annual plasma metanephrine measurement, and intermittent MRI of pituitary and base of skull to coccyx. Conclusion: Macroprolactinomas are relatively common, with only a small proportion associated with underlying genetic abnormalities. This case describes a patient with 3PAs, initially presenting with a macroprolactinoma, with incidental detection of phaeochromocytoma and paraganglioma and subsequent identification of a pathogenic SDHA mutation. In the context of a calcified bicuspid aortic valve and severe aortic dilatation, pre-operative alpha blockade allowed successful surgical management of both potentially life-threatening conditions. Presentation: 6/3/2024

12466 Dual Bone Defect In Patients With Charge Syndrome

Abstract Disclosure: N. Reyes: None. R.J. Santen: None. S.M. Jan De Beur: None. R. Balasubramanian: None. Chromodomain Helicase DNA-binding protein 7 (Chd7) is an ATP-dependent chromatin modifier that mediates nucleosome remodeling. Chd7 mutations result in CHARGE syndrome characterized by coloboma, heart defects, choanal atresia, growth/developmental delay, ear abnormalities, and hypogonadotropic hypogonadism/Kallmann syndrome (IHH/KS). Testosterone has direct and indirect effects (through estrogen), to increase bone formation and decrease bone resorption. Untreated hypogonadism is associated with decreased bone density and fractures. Reports of fractures and low bone density in CHARGE syndrome patients have been attributed to sex hormone deficiency associated with hypogonadism. However, recent data from a Chd7 mouse knockout model suggests an intrinsic Chd7-related bone defect. In wild-type mice, Chd7 promotes osteogenic differentiation of mesenchymal stem cells. Chd7 deficient mice show markedly reduced osteoblasts. Thus, we propose, a dual bone defect in CHARGE syndrome resulting from impaired osteogenesis from CHD7 and sex steroid deficiency; and increased bone resorption due to lack of sex steroids. Here we present two individuals with CHARGE syndrome with markedly low bone density and literature review supporting the dual bone defect concept. Case 1 is a 30 yo male with a pathogenic CHD7 mutation, multiple congenital anomalies of CHARGE syndrome and hypogonadotropic hypogonadism. He had multiple fractures in his teen age years and a bone density Z score of -5.2 at the lumbar spine and -3.3 at the left femoral neck. Because he did not tolerate androgen therapy, a single infusion of zoledronic acid was administered with no further fractures for eight years following infusion. Case 2 is a male evaluated for IHH/KS and ultimately diagnosed with CHARGE Syndrome based on a pathogenic CHD7 mutation. Despite 7 years of testosterone therapy with full virilization, his bone density remained low at Z-score of -1.9 at the spine and -2.6 at the total hip. Results: Both patients had low bone density, one while untreated and the other after full virilization with exogenous androgens. This raises the question whether the bone defects were related to the CHD7 mutation, to androgen deficiency or both. To answer this question, a literature search examined bone density data in untreated patients with CHARGE syndrome versus IHH/KS. We found substantially lower bone density in untreated CHARGE patients Z score -3.46±0.36 (SEM) (n=13) versus IHH/KS -2.16 ±1.0 (n=4). Furthermore, the bone density was also lower in treated CHARGE patients -2.46±0.28 (n=6) versus IHH/KS -0.94±0.26 (n=140). Conclusion: These data, taken together, provide direct human evidence to support the concept that the CHD7-related CHARGE syndrome patients have a defect in both osteogenesis as well as an effect of sex steroid deficiency on bone. Presentation: 6/3/2024

8207 Insights From a Case of Insulinoma and Possible Genetic Variants in a Young Woman With Recurrent Hypoglycemia

Abstract Disclosure: M.A. Brandao: None. A. Bharara: None. V.I. Moncada Castro: None. T.C. Tsai: None. Y. Wu: None. S. Marquez Flores: None. K. Divari: None. Introduction: Insulinomas are neuroendocrine neoplasms causing hyperinsulinemic hypoglycemia. They are rare, with a prevalence of 1-4 people per million of the general population. Key features are symptoms of hypoglycemia, low plasma glucose, and symptom relief by correcting hypoglycemia. Here, we report a patient with recurrent hypoglycemia who was found to have insulinoma. Several variants of uncertain significance (VUS) were detected in this patient. This gives us some insights into a broader perspective. Clinical case: A 28-year-old healthy female was found unresponsive by her partner. Blood glucose (BG) was 40 mg/dL when paramedics arrived. She received dextrose and rapidly recovered. She was briefly hospitalized and received glucose infusion with improvement. Subsequently, the patient developed episodes of blurry vision and weakness. She had been eating more frequently to prevent symptoms. Her weight was stable at 65.77 kg. She had not been on any medications. She continued to experience hypoglycemic episodes with BG dropping to 30 mg/dL, so she sought evaluation from an endocrinologist. Laboratory work-up showed Proinsulin of 530.6 pmol/L, C-peptide 5 ng/ml, TSH 1.01 mciu/ml, Beta-hydroxybutyrate (BHOB) 0.7 mg/dL, hemoglobin A1c 4.7%, calcium 8.9 mg/dL, albumin 4.1. Abdominal computed tomography (CT) scan showed an 11 mm nodule anterior to the pancreatic tail. No discrete calcification was noted. Magnetic resonance imaging (MRI) of the abdomen redemonstrated the 10 x 6mm, slightly exophytic lesion in the pancreatic tail. Therefore, she underwent laparoscopic enucleation with pathology showing a 1.7cm well-differentiated grade 2 neuroendocrine tumor, with positive margins. Given its indolent nature, further surgical resection was not recommended. Germline testing showed several VUS: the AXIN2 gene (c.1822C&amp;gt;G), GPC3 gene (c.565G&amp;gt;T), NF2 gene (c.296A&amp;gt;G), RECQL4 gene (c.2791C&amp;gt;G). However, no pathogenic variants were identified. Surveillance MRI of the abdomen six months after the surgery has shown no evidence of recurrent disease. The patient has remained euglycemic and symptoms have not recurred. Conclusion: Insulinomas are typically sporadic but may occur due to an activating T372R mutation in the Yin Yang. It may also occur in the setting of multiple endocrine neoplasia type 1 (MEN-1) syndrome caused by MEN1 gene mutations. Although no pathogenic variant mutations associated with insulinoma were found, several VUS that have not yet been described as related to insulinoma were detected in this patient. Routine genetic testing in newly diagnosed patients is not always recommended. Therefore, further efforts are required to understand genetic mutations and epigenetic modifiers associated with insulinoma. Validation of identified VUS and additional genetic testing in young patients with insulinoma are crucial. Presentation: 6/2/2024

7925 Cowden Disease Occurring in Association with Common Variable Hypogammaglobulinemia: A Case Report

Abstract Disclosure: M.K. Shakir: None. I.C. Ebrahim: None. D.B. Maxwell: None. N.O. Vietor: None. T.D. Hoang: None. Carriers of a pathogenic germline mutations in the PTEN gene, a tumor suppressor gene, are at increased risk of multiple benign and malignant tumors, including thyroid, breast, endometrial and colon cancer, termed as PTEN Hamartoma Tumor Syndrome (PHTS). Recent studies have shown that PHTS patients may also have an increased risk of immunological dysregulation, such as autoimmunity and immune deficiencies. We are reporting a 47-year-old female with Cowden disease (CD) and common variable hypogammaglobulinemia (CVH). Our patient was diagnosed with CVH at the age of 25 after several episodes of pneumonia as well as poor wound healing. Since then, she is being treated with monthly intravenous immunoglobulin therapy. At the age of 24 years, she had a fainting episode and a diagnosis of gangliocytoma of cerebellum was made and she underwent resection of the tumor. At this time, she was also diagnosed with CD. She has a personal history of multiple other tumors including phyllodes tumor of breast, s/p bilateral mastectomy at the age of 32, status post hysterectomy for endometrial hyperplasia at the age 35. Hurthle cell adenomas of thyroid s/p total thyroidectomy at the age of 38. Her family history was significant for sister and father with CD. Physical examination was remarkable for only acral keratosis without mucocutaneous neuromas, oral papillomas and trichilemmomas. Cowden syndrome is the best-described phenotype of PHTS; it is characterized by mucocutaneous lesions and an elevated risk of breast, thyroid, endometrial, colorectal, and renal cancers as well as various benign manifestations such as macrocephaly and dysplastic gangliocytoma of the cerebellum. Our patient was diagnosed with CD when she presented with gangliocytoma of the cerebellum. Immunodeficiency has been reported previously in patients with CD, and these patients often present with recurrent cellulitis and abscesses, and reduced T cell numbers and in vitro T cell proliferative function. Thus, PHTS patients may also have an increased risk of immunological dysregulation, such as autoimmunity and immune deficiencies. Additionally, a decreased ability of dendritic cells to prime CD8+ T cells may occur, leading to impaired tumor eradication. Immune dysfunction in PHTS patients might be a potentially manageable contributing factor to the increased cancer risk in PHTS. In conclusion, patients presenting with CD should also be screened for disorders of immunological dysregulation. Presentation: 6/2/2024