Metabolic reprogramming regulated by TRAF6 contributes to the leukemia progression.

TNF receptor associated factor 6 (TRAF6) is an E3 ubiquitin ligase that has been implicated in myeloid malignancies. Although altered TRAF6 expression is observed in human acute myeloid leukemia (AML), its role in the AML pathogenesis remains elusive. In this study, we showed that the loss of TRAF6 in AML cells significantly impairs leukemic function in vitro and in vivo, indicating its functional importance in AML subsets. Loss of TRAF6 induces metabolic alterations, such as changes in glycolysis, TCA cycle, and nucleic acid metabolism as well as impaired mitochondrial membrane potential and respiratory capacity. In leukemic cells, TRAF6 expression shows a positive correlation with the expression of O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT), which catalyzes the addition of O-GlcNAc to target proteins involved in metabolic regulation. The restoration of growth capacity and metabolic activity in leukemic cells with TRAF6 loss, achieved through either forced expression of OGT or pharmacological inhibition of O-GlcNAcase (OGA) that removes O-GlcNAc, indicates the significant role of O-GlcNAc modification in the TRAF6-related cellular and metabolic dynamics. Our findings highlight the oncogenic function of TRAF6 in leukemia and illuminate the novel TRAF6/OGT/O-GlcNAc axis as a potential regulator of metabolic reprogramming in leukemogenesis.

Efficacy and Safety of Pemafibrate Extended-Release Tablet: a Phase 3, Multicenter, Randomized, Double-Blind, Active-Controlled, Parallel-Group Comparison Trial.

AIMS: Pemafibrate, a selective peroxisome proliferator-activated receptor α modulator that lowers serum triglyceride levels and increases high-density lipoprotein cholesterol levels, is approved for treating dyslipidemia as twice-daily immediate-release (IR) tablets. A once-daily extended-release (XR) tablet has also been developed. We aimed to confirm the non-inferiority of XR (0.2 or 0.4 mg/day; once daily) to IR (0.2 mg/day; twice daily) in lowering triglyceride levels in patients with hypertriglyceridemia. METHODS: This phase 3, multicenter, randomized, double-blind study included patients with fasting triglycerides ≥ 200 mg/dL who received IR (0.2 mg/day) or XR (0.2 or 0.4 mg/day). The primary efficacy endpoint was the percentage change in fasting triglyceride levels from baseline to 4, 8, and 12 weeks. Common treatment effects at weeks 4 through 12 were compared between groups using repeated analysis of covariance. RESULTS: In 356 randomized patients, fasting triglyceride levels decreased by 48.0%, 43.8%, and 48.0% with IR 0.2, XR 0.2, and XR 0.4 mg/day, respectively, confirming the non-inferiority of both XR regimens to IR. The proportion of patients who achieved fasting triglycerides ＜150 mg/dL was 45.7%, 37.4%, and 51.7%, while the percentage change of triglycerides in the subgroup with baseline triglycerides ≥ 500 mg/dL was -59.3%, -52.2%, and -66.3% with IR 0.2, XR 0.2, and XR 0.4 mg/day, respectively. CONCLUSIONS: XR (0.2 and 0.4 mg/day) was non-inferior to IR (0.2 mg/day). XR 0.4 mg/day demonstrated a more potent triglyceride-lowering effect than XR 0.2 mg/day and should be considered for patients with high triglyceride levels.

Increasing Catecholamine Secretion Through NPY in Pheochromocytomas With False-Negative 123 I-MIBG Scintigraphy.

INTRODUCTION: 123 I-MIBG has been well established as a functional imaging tool, and 131 I-MIBG therapy is being considered for catecholamine-secreting tumors. Tumors with the characteristics of a noradrenergic biochemical phenotype, small, malignant, metastatic, extra-adrenal, bilateral, and hereditary, especially SDHx -related tumors, are reported to correlate with reduced MIBG uptake. However, the potential molecular mechanisms influencing MIBG uptake have been poorly studied. PATIENTS AND METHODS: To identify critical genes that may enhance MIBG accumulation in pheochromocytomas (PCCs), we performed RNA-seq analyses for 16 operated patients with PCCs (6 MIBG-negative and 10 MIBG-positive) combined with RT-qPCR for 27 PCCs (5 MIBG-negative and 22 MIBG-positive) and examined primary cultures of the surgical tissues. RESULTS: In the present study, 6 adrenal nodules of 66 nodules surgically removed from 63 patients with PCCs (9%) were MIBG negative. MIBG, a guanethidine analog of norepinephrine, can enter chromaffin cells through active uptake via the cellular membrane, be deposited in chromaffin granules, and be released via Ca 2+ -triggered exocytosis from adrenal chromaffin cells. When we compared expression of several catecholamine biosynthesis and secretion-associated genes between MIBG-negative and MIBG-positive tumors using transcriptome analyses, we found that neuropeptide Y, which is contained in chromaffin granules, was significantly increased in MIBG-negative tumors. NPY stimulated norepinephrine secretion dose-dependently in primary cell culture derived from MIBG-positive PCC. In our study, MIBG-negative PCCs were all norepinephrine-hypersecreting tumors. CONCLUSIONS: These data indicate that NPY upregulation in PCCs may stimulate chromaffin granule catecholamine secretion, which is associated with false-negative 123 I-MIBG scintigraphy.

Familial hypercholesterolemia with special focus on Japan.

Familial hypercholesterolemia (FH) is an inherited disorder characterized by increased low-density lipoprotein LDL) cholesterol and atherosclerotic cardiovascular disease. Although initial genetic analysis linked FH to LDL receptor mutations, subsequent work demonstrated that a gain-of-function mutation in the proprotein convertase subtilisin/kexin type 9 (PCSK9), which causes LDL-R degradation, was shown to be the cause of FH. In this review, we describe the history of research on FH, its clinical phenotyping and genotyping and advances in treatment with special focus on Japan.

Sodium-glucose co-transporter 2 inhibitor therapy reduces the administration frequency of anti-vascular endothelial growth factor agents in patients with diabetic macular oedema with a history of anti-vascular endothelial growth factor agent use: A cohort study using the Japanese health insurance claims database.

AIM: We assessed the effectiveness of sodium-glucose co-transporter 2 inhibitors (SGLT2is) in reducing the administration frequency of anti-vascular endothelial growth factor (VEGF) agents in patients with diabetic macular oedema (DMO) using a health insurance claims database. MATERIALS AND METHODS: This retrospective cohort study analysed health insurance claims data covering 11 million Japanese patients between 2005 and 2019. We analysed the frequency and duration of intravitreal injection of anti-VEGF agents after initiating SGLT2is or other antidiabetic drugs. RESULTS: Among 2412 matched patients with DMO, the incidence rates of anti-VEGF agent injections were 230.1 per 1000 person-year in SGLT2i users and 228.4 times per 1000 person-year in non-users, respectively, and the risk ratio for events was unchanged in both groups. Sub-analysis of each baseline characteristic of the patients showed that SGLT2is were particularly effective in patients with a history of anti-VEGF agent use [p = .027, hazard ratio (HR): 0.44, 95% confidence interval (CI): 0.22-0.91]. SGLT2is reduced the risk for the first (p = .023, HR: 0.45, 95% CI: 0.22-0.91) and second (p = .021, HR: 0.39, 95% CI: 0.17-0.89) anti-VEGF agent injections. CONCLUSIONS: There was no difference in the risk ratio for the addition of anti-VEGF therapy between the two treatment groups. However, the use of SGLT2is reduced the frequency of anti-VEGF agent administration in patients with DMO requiring anti-VEGF therapy. Therefore, SGLT2i therapy may be a novel, non-invasive, low-cost adjunctive therapy for DMO requiring anti-VEGF therapy.

Meeting Summary of The NYO3 5th NO-Age/AD Meeting and the 1st Norway-UK Joint Meeting on Aging and Dementia: Recent Progress on the Mechanisms and Interventional Strategies.

Unhealthy aging poses a global challenge with profound healthcare and socioeconomic implications. Slowing down the aging process offers a promising approach to reduce the burden of a number of age-related diseases, such as dementia, and promoting healthy longevity in the old population. In response to the challenge of the aging population and with a view to the future, Norway and the United Kingdom are fostering collaborations, supported by a "Money Follows Cooperation agreement" between the 2 nations. The inaugural Norway-UK joint meeting on aging and dementia gathered leading experts on aging and dementia from the 2 nations to share their latest discoveries in related fields. Since aging is an international challenge, and to foster collaborations, we also invited leading scholars from 11 additional countries to join this event. This report provides a summary of the conference, highlighting recent progress on molecular aging mechanisms, genetic risk factors, DNA damage and repair, mitophagy, autophagy, as well as progress on a series of clinical trials (eg, using NAD+ precursors). The meeting facilitated dialogue among policymakers, administrative leaders, researchers, and clinical experts, aiming to promote international research collaborations and to translate findings into clinical applications and interventions to advance healthy aging.

Sex differences in symptom presentation and their impact on diagnostic accuracy in Werner syndrome.

AIM: Whether sex differences exist in hereditary progeroid syndromes remains unclear. In this study, we investigated sex differences in patients with Werner syndrome (WS), a model of human aging, using patient data at the time of diagnosis. METHODS: The presence of six cardinal signs in the diagnostic criteria was retrospectively evaluated. RESULTS: We found that the percentage of patients with all cardinal signs was higher in males than in females (54.2% vs. 21.2%). By the age of 40 years, 57.1% of male patients with WS presented with all the cardinal signs, whereas none of the female patients developed all of them. In particular, the frequency of having a high-pitched, hoarse voice, a characteristic of WS, was lower in female patients. The positive and negative predictive values for clinical diagnosis were 100% for males and females, indicating the helpfulness of diagnostic criteria regardless of sex. More female patients than male (86.7% vs. 64%) required genetic testing for their diagnosis because their clinical symptoms were insufficient, suggesting the importance of genetic testing for females even if they do not show typical symptoms of WS. Finally, the frequency of abnormal voice was lower in patients with WS harboring the c.3139-1G > C homozygous mutation. CONCLUSION: These results indicate, for the first time, that there are sex differences in the phenotypes of hereditary progeroid syndromes. The analysis of this mechanism in this human model of aging may lead to the elucidation of sex differences in the various symptoms of normal human aging. Geriatr Gerontol Int 2024; 24: 161-167.

Long-term Efficacy and Safety of K-924 Pitavastatin/Ezetimibe Fixed-dose Combination in Patients with Hypercholesterolemia: A Phase III, Multi-center, Open-label Trial.

AIM: Ezetimibe administration with ongoing statin therapy is an effective option for further lowering low-density lipoprotein cholesterol (LDL-C) levels. Thus, we investigated the long-term efficacy and safety of fixed-dose combination of pitavastatin/ezetimibe (K-924 LD: 2 mg/10 mg; K-924 HD: 4 mg/10 mg). METHODS: We conducted a phase III, multicenter, open-label trial involving patients with hypercholesterolemia receiving pitavastatin (2 or 4 mg) who had not achieved their LDL-C management target. Patients were enrolled into the K-924 LD and HD groups based on whether they had received pitavastatin 2 and 4 mg, respectively, and treated for 52 weeks. K-924 was administered orally once daily. The primary objective was to examine the percent change in LDL-C from baseline at week 52 with last observation carried forward imputation (LOCF) in all patients. RESULTS: Of the 109 patients evaluated, 62 and 47 were assigned to the K-924 LD and HD groups, respectively. In all patients, LDL-C decreased by -30.3±14.3% (p＜0.001) from baseline (134.4±37.9 mg/dL). Consequently, 91.8% and 37.5% of the patients for primary and secondary prevention reached their LDL-C management target, respectively. These results were consistent in both the K-924 LD and HD groups. In the safety analysis, a single adverse drug reaction occurred in a patient in the K-924 HD group. CONCLUSION: After replacing pitavastatin monotherapy, K-924 was found to be effective and well-tolerated over 52 weeks. Thus, K-924 can contribute to intensifying LDL-C-lowering therapy without increasing the number of medications.

Definition, criteria, and core concepts of guidelines for the management of obesity disease in Japan.

To identify those who might benefit from weight reduction within a large population of obese individuals, Japan Society for the Study of Obesity (JASSO) advocated the concept of "obesity disease." Here we summarize the definition, criteria, and core concepts for the management of obesity disease based on JASSO's latest guideline. JASSO defines obesity as excessive fat storage in adipose tissue associated with a BMI of ≥25 kg/m2. The threshold BMI of obesity is low as compared to Western countries given that Japanese individuals tend to develop obesity-related health disorders at lower BMI. Obesity with a BMI of ≥35 kg/m2 is referred to as "high-degree obesity" as treatment strategies vary based on the degree of obesity. Obesity is diagnosed as "obesity disease" if accompanied by any of the 11 specific obesity-related health disorders that weight reduction can prevent or alleviate, or if it meets the criteria for visceral fat obesity with a visceral fat area of ≥100 cm2. The initial weight reduction goals for high-degree obesity disease range from 5% to 10% of their current body weight, depending on the associated health disorders. That for those with obesity disease who do not qualify as high-degree is 3% or more. If these initial goals are not achieved, intensifying dietary therapy or introducing drug therapy (or both) may be necessary. While surgical treatment is primarily indicated for high-degree obesity disease, it might be appropriate for cases of obesity disease with a BMI <35 kg/m2, depending on the accompanying health disorders. Enhancing the quality of life for individuals with obesity or obesity disease necessitates a broader societal approach, emphasizing the resolution of related stigma.

Challenges in the diagnosis of the enigmatic primary adrenal leiomyosarcoma: two case reports and review of the literature.

BACKGROUND: Primary adrenal leiomyosarcoma is a rare and aggressive mesenchymal tumor derived from the smooth muscle wall of a central adrenal vein or its tributaries; therefore, tumors tend to invade the inferior vena cava and cause thrombosis. The great majority of tumors grow rapidly, which makes the disease difficult to diagnose in its early clinical stages and needs differentiation from adrenocortical carcinomas for the selection of chemotherapy including mitotane which causes adrenal insufficiency. CASE PRESENTATION: We presented two patients with adrenal leiomyosarcoma who were referred to our hospital with abdominal pain and harboring large adrenal tumors and inferior vena cava thrombosis. The endocrine findings, including serum catecholamine levels, were unremarkable. These two patients were considered clinically inoperable, and CT-guided core needle biopsy was performed to obtain the definitive histopathological diagnosis and determine the modes of therapy. The masses were subsequently diagnosed as primary adrenal leiomyosarcoma based on the histological features and positive immunoreactivity for SMA (smooth muscle actin), desmin, and vimentin. CONCLUSIONS: Adrenal leiomyosarcoma derived from the smooth muscle wall of a central adrenal vein or its tributaries is rare but should be considered a differential diagnosis in the case of nonfunctioning adrenal tumors extending directly to the inferior vena cava. CT-guided biopsy is considered useful for histopathological diagnosis and clinical management of patients with inoperable advanced adrenal tumors without any hormone excess.

The USP7-STAT3-granzyme-Par-1 axis regulates allergic inflammation by promoting differentiation of IL-5-producing Th2 cells.

Uncontrolled type 2 immunity by type 2 helper T (Th2) cells causes intractable allergic diseases; however, whether the interaction of CD4+ T cells shapes the pathophysiology of allergic diseases remains unclear. We identified a subset of Th2 cells that produced the serine proteases granzyme A and B early in differentiation. Granzymes cleave protease-activated receptor (Par)-1 and induce phosphorylation of p38 mitogen-activated protein kinase (MAPK), resulting in the enhanced production of IL-5 and IL-13 in both mouse and human Th2 cells. Ubiquitin-specific protease 7 (USP7) regulates IL-4-induced phosphorylation of STAT3, resulting in granzyme production during Th2 cell differentiation. Genetic deletion of Usp7 or Gzma and pharmacological blockade of granzyme B ameliorated allergic airway inflammation. Furthermore, PAR-1+ and granzyme+ Th2 cells were colocalized in nasal polyps from patients with eosinophilic chronic rhinosinusitis. Thus, the USP7-STAT3-granzymes-Par-1 pathway is a potential therapeutic target for intractable allergic diseases.

Serum anti-PCK1 antibody levels are a prognostic factor for patients with diabetes mellitus.

BACKGROUND: Autoantibodies develop in autoimmune diseases, cancer, diabetes mellitus (DM), and atherosclerosis-related diseases. However, autoantibody biomarkers have not been successfully examined for diagnosis and therapy. METHODS: Serological identification of antigens through recombinant cDNA expression cloning (SEREX) was used for primary screening of antigens. The cDNA product was expressed in bacteria and purified. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) was used to evaluate antibody levels in serum samples. RESULTS: Phosphoenolpyruvate carboxykinase 1 (PCK1) was recognized as an antigen by serum IgG antibodies in the sera of patients with atherosclerosis. AlphaLISA showed significantly higher serum antibody levels against recombinant PCK1 protein in patients with DM and cardiovascular disease than in healthy donors, but not in those with acute ischemic stroke, transient ischemic attack, or obstructive sleep apnea syndrome. The area under the receiver operating characteristic curve for anti-PCK1 antibodies was 0.7024 for DM. The serum anti-PCK1 antibody levels were associated with age, platelet count, and blood pressure. Anti-PCK1-antibody-positive patients showed significantly lower overall survival than the negative patients. CONCLUSIONS: Serum anti-PCK1 antibody levels were found to be associated with DM. The anti-PCK1 antibody marker is useful for predicting the overall survival of patients with DM.

Senescence-associated inflammation and inhibition of adipogenesis in subcutaneous fat in Werner syndrome.

Werner syndrome (WS) is a hereditary premature aging disorder characterized by visceral fat accumulation and subcutaneous lipoatrophy, resulting in severe insulin resistance. However, its underlying mechanism remains unclear. In this study, we show that senescence-associated inflammation and suppressed adipogenesis play a role in subcutaneous adipose tissue reduction and dysfunction in WS. Clinical data from four Japanese patients with WS revealed significant associations between the decrease of areas of subcutaneous fat and increased insulin resistance measured by the glucose clamp. Adipose-derived stem cells from the stromal vascular fraction derived from WS subcutaneous adipose tissues (WSVF) showed early replicative senescence and a significant increase in the expression of senescence-associated secretory phenotype (SASP) markers. Additionally, adipogenesis and insulin signaling were suppressed in WSVF, and the expression of adipogenesis suppressor genes and SASP-related genes was increased. Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), alleviated premature cellular senescence, rescued the decrease in insulin signaling, and extended the lifespan of WS model of C. elegans. To the best of our knowledge, this study is the first to reveal the critical role of cellular senescence in subcutaneous lipoatrophy and severe insulin resistance in WS, highlighting the therapeutic potential of rapamycin for this disease.

Insulin resistance induces earlier initiation of cognitive dysfunction mediated by cholinergic deregulation in a mouse model of Alzheimer's disease.

Although insulin resistance increases the risk of Alzheimer's disease (AD), the mechanisms remain unclear, partly because no animal model exhibits the insulin-resistant phenotype without persistent hyperglycemia. Here we established an AD model with whole-body insulin resistance without persistent hyperglycemia (APP/IR-dKI mice) by crossbreeding constitutive knock-in mice with P1195L-mutated insulin receptor (IR-KI mice) and those with mutated amyloid precursor protein (AppNL-G-F mice: APP-KI mice). APP/IR-dKI mice exhibited cognitive impairment at an earlier age than APP-KI mice. Since cholinergic dysfunction is a major characteristic of AD, pharmacological interventions on the cholinergic system were performed to investigate the mechanism. Antagonism to a nicotinic acetylcholine receptor α7 (nAChRα7) suppressed cognitive function and cortical blood flow (CBF) response to cholinergic-regulated peripheral stimulation in APP-KI mice but not APP/IR-dKI mice. Cortical expression of Chrna7, encoding nAChRα7, was downregulated in APP/IR-dKI mice compared with APP-KI. Amyloid ß burden did not differ between APP-KI and APP/IR-dKI mice. Therefore, insulin resistance, not persistent hyperglycemia, induces the earlier onset of cognitive dysfunction and CBF deregulation mediated by nAChRα7 downregulation. Our mouse model will help clarify the association between type 2 diabetes mellitus and AD.

Imeglimin-mediated glycemic control in maternally inherited deafness and diabetes.

Mitochondrial dysfunction causes maternally inherited deafness and diabetes (MIDD). Herein, we report improved glycemic control in a 47-year-old Japanese woman with MIDD using imeglimin without major adverse effects. Biochemical tests and metabolome analysis were performed before and after imeglimin administration. Blood glucose level fluctuations were determined. Sulfonylureas, dipeptidyl peptidase-4 inhibitors (DPP4is), and sodium glucose transporter-2 inhibitors (SGLT2i) were administered to evaluate the efficacy of their combination with imeglimin. Imeglimin decreased the HbA1c and ammonia levels and increased the time-in-range, C-peptide reactivity, and glucagon level. Elevated citrulline and histamine levels were decreased by imeglimin. The hypoglycemic effect was not enhanced by imeglimin when combined with sulfonylurea or DPP4i, but the blood glucose level was improved when combined with SGLT2i. Imeglimin improved glucose concentration-dependent insulin secretion and maximized the insulin secretory capacity by improving mitochondrial function and glutamine metabolism and urea circuit abnormalities by promoting glucagon secretion. Imeglimin could improve glycemic control in MIDD.

Metabolomic analysis of serum samples from a clinical study on ipragliflozin and metformin treatment in Japanese patients with type 2 diabetes: Exploring human metabolites associated with visceral fat reduction.

STUDY OBJECTIVE: The effects of the sodium-dependent glucose transporter-2 inhibitor ipragliflozin were compared with metformin in a previous study, which revealed that ipragliflozin reduced visceral fat content by 12%; however, the underlying mechanism was unclear. Therefore, this sub-analysis aimed to compare metabolomic changes associated with ipragliflozin and metformin that may contribute to their biological effects. DESIGN: A sub-analysis of a randomized controlled study. SETTING: Chiba University Hospital and ten hospitals in Japan. PATIENTS: Fifteen patients with type 2 diabetes in the ipragliflozin group and 15 patients with type 2 diabetes in the metformin group with matching characteristics, such as age, sex, baseline A1C, baseline visceral fat area, smoking status, and concomitant medication. INTERVENTIONS: Ipragliflozin 50 mg or metformin 1000 mg daily. MEASUREMENTS: The clinical data were reanalyzed, and metabolomic analysis of serum samples collected before and 24 weeks after drug administration was performed using capillary electrophoresis time-of-flight mass spectrometry. MAIN RESULTS: The reduction in the mean visceral fat area after 24 weeks of treatment was significantly larger (p = 0.002) in the ipragliflozin group (-19.8%) than in the metformin group (-2.5%), as were the subcutaneous fat area and body weight. The A1C and blood glucose levels decreased in both groups. Glutamic pyruvic oxaloacetic transaminase, γ-glutamyl transferase, uric acid, and triglyceride levels decreased in the ipragliflozin group. Low-density lipoprotein cholesterol levels decreased in the metformin group. After ipragliflozin administration, N2-phenylacetylglutamine, inosine, guanosine, and 1-methyladenosine levels increased, whereas galactosamine, glucosamine, 11-aminoundecanoic acid, morpholine, and choline levels decreased. After metformin administration, metformin, hypotaurine, methionine, methyl-2-oxovaleric acid, 3-nitrotyrosine, and cyclohexylamine levels increased, whereas citrulline, octanoic acid, indole-3-acetaldehyde, and hexanoic acid levels decreased. CONCLUSIONS: Metabolites that may affect visceral fat reduction were detected in the ipragliflozin group. Studies are required to further elucidate the underlying mechanisms.

Identification of genotype-biochemical phenotype correlations associated with fructose 1,6-bisphosphatase deficiency.

Fructose-1,6-bisphosphatase (FBPase) deficiency, caused by an FBP1 mutation, is an autosomal recessive disorder characterized by hypoglycemic lactic acidosis. Due to the rarity of FBPase deficiency, the mechanism by which the mutations cause enzyme activity loss still remains unclear. Here we identify compound heterozygous missense mutations of FBP1, c.491G>A (p.G164D) and c.581T>C (p.F194S), in an adult patient with hypoglycemic lactic acidosis. The G164D and F194S FBP1 mutants exhibit decreased FBP1 protein expression and a loss of FBPase enzyme activity. The biochemical phenotypes of all previously reported FBP1 missense mutations in addition to G164D and F194S are classified into three functional categories. Type 1 mutations are located at pivotal residues in enzyme activity motifs and have no effects on protein expression. Type 2 mutations structurally cluster around the substrate binding pocket and are associated with decreased protein expression due to protein misfolding. Type 3 mutations are likely nonpathogenic. These findings demonstrate a key role of protein misfolding in mediating the pathogenesis of FBPase deficiency, particularly for Type 2 mutations. This study provides important insights that certain patients with Type 2 mutations may respond to chaperone molecules.