Circulating Metabolite Abundances Associated With Risks of Bipolar Disorder, Schizophrenia, and Depression: A Mendelian Randomization Study.

BACKGROUND: Preventive measures and treatments for psychiatric disorders are limited. Circulating metabolites are potential candidates for biomarker and therapeutic target identification, given their measurability and essential roles in biological processes. METHODS: Leveraging large-scale genome-wide association studies, we conducted Mendelian randomization analyses to assess the associations between circulating metabolite abundances and the risks of bipolar disorder, schizophrenia, and depression. Genetic instruments were selected for 94 metabolites measured in the Canadian Longitudinal Study on Aging cohort (N = 8299). We repeated Mendelian randomization analyses based on the UK Biobank, INTERVAL, and EPIC (European Prospective Investigation into Cancer)-Norfolk studies. RESULTS: After validating Mendelian randomization assumptions and colocalization evidence, we found that a 1 SD increase in genetically predicted circulating abundances of eicosapentaenoate and docosapentaenoate was associated with odds ratios of 0.72 (95% CI, 0.65-0.79) and 0.63 (95% CI, 0.55-0.72), respectively, for bipolar disorder. Genetically increased Ω-3 unsaturated fatty acids abundance and Ω-3-to-total fatty acids ratio, as well as genetically decreased Ω-6-to-Ω-3 ratio, were negatively associated with the risk of bipolar disorder in the UK Biobank. Genetically increased circulating abundances of 3 N-acetyl-amino acids were associated with an increased risk of schizophrenia with a maximum odds ratio of 1.31 (95% CI, 1.18-1.44) per 1 SD increase. Furthermore, a 1 SD increase in genetically predicted circulating abundance of hypotaurine was associated with an odds ratio of 0.85 (95% CI, 0.78-0.93) for depression. CONCLUSIONS: The biological mechanisms that underlie Ω-3 unsaturated fatty acids, NAT8-catalyzed N-acetyl-amino acids, and hypotaurine warrant exploration to identify new biomarkers and potential therapeutic targets.

Increasing serum iron levels and their role in the risk of infectious diseases: a Mendelian randomization approach.

OBJECTIVES: Increased iron stores have been associated with elevated risks of different infectious diseases, suggesting that iron supplementation may increase the risk of infections. However, these associations may be biased by confounding or reverse causation. This is important, since up to 19% of the population takes iron supplementation. We used Mendelian randomization (MR) to bypass these biases and estimate the causal effect of iron on infections. METHODS: As instrumental variables, we used genetic variants associated with iron biomarkers in two genome-wide association studies (GWASs) of European ancestry participants. For outcomes, we used GWAS results from the UK Biobank, FinnGen, the COVID-19 Host Genetics Initiative or 23andMe, for seven infection phenotypes: 'any infections', combined, COVID-19 hospitalization, candidiasis, pneumonia, sepsis, skin and soft tissue infection (SSTI) and urinary tract infection (UTI). RESULTS: Most of our analyses showed increasing iron (measured by its biomarkers) was associated with only modest changes in the odds of infectious outcomes, with all 95% odds ratios confidence intervals within the 0.88 to 1.26 range. However, for the three predominantly bacterial infections (sepsis, SSTI, UTI), at least one analysis showed a nominally elevated risk with increased iron stores (P <0.05). CONCLUSION: Using MR, we did not observe an increase in risk of most infectious diseases with increases in iron stores. However for bacterial infections, higher iron stores may increase odds of infections. Hence, using genetic variation in iron pathways as a proxy for iron supplementation, iron supplements are likely safe on a population level, but we should continue the current practice of conservative iron supplementation during bacterial infections or in those at high risk of developing them.

First Japanese Family With PDX1-MODY (MODY4): A Novel PDX1 Frameshift Mutation, Clinical Characteristics, and Implications.

CONTEXT: The PDX1 gene encodes pancreatic and duodenal homeobox, a critical transcription factor for pancreatic ß-cell differentiation and maintenance of mature ß-cells. Heterozygous loss-of-function mutations cause PDX1-MODY (MODY4). CASE DESCRIPTION: Our patient is an 18-year-old lean man who developed diabetes at 16 years of age. Given his early-onset age and leanness, we performed genetic testing. Targeted next-generation sequencing and subsequent Sanger sequencing detected a novel heterozygous frameshift mutation (NM_00209.4:c.218delT. NP_000200.1: p.Leu73Profs*50) in the PDX1 transactivation domain that resulted in loss-of-function and was validated by an in vitro functional study. The proband and his 56-year-old father, who had the same mutation, both showed markedly reduced insulin and gastric inhibitory polypeptide (GIP) secretion compared with the dizygotic twin sister, who was negative for the mutation and had normal glucose tolerance. The proband responded well to sitagliptin, suggesting its utility as a treatment option. Notably, the proband and his father showed intriguing phenotypic differences: the proband had been lean for his entire life but developed early-onset diabetes requiring an antihyperglycemic agent. In contrast, his father was overweight, developed diabetes much later in life, and did not require medication, suggesting the oligogenic nature of PDX1-MODY. A review of all reported cases of PDX1-MODY also showed heterogeneous phenotypes regarding onset age, obesity, and treatment, even in the presence of the same mutation. CONCLUSIONS: We identified the first Japanese family with PDX1-MODY. The similarities and differences found among the cases highlight the wide phenotypic spectrum of PDX1-MODY.

Alu-Mediated MEN1 Gene Deletion and Loss of Heterozygosity in a Patient with Multiple Endocrine Neoplasia Type 1.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder caused by mutations of the tumor suppressor gene MEN1. Most of the germline MEN1 gene mutations have been small mutations, and the whole gene deletion is rarely observed. In the present study, we revealed Alu retrotransposon-mediated de novo germline deletion of the whole MEN1 gene and somatic copy-neutral loss of heterozygosity (LOH) in a patient with MEN1. The patient is a 39-year-old woman who was referred to our department for the management of prolactinoma. She was also diagnosed with primary hyperparathyroidism and suspected of MEN1. Although nucleotide sequencing did not detect any MEN1 gene mutations, multiplex ligation-dependent probe amplification (MLPA) revealed a large germline deletion of the MEN1 gene. Subsequent quantitative polymerase chain reaction (qPCR)-based copy number mapping showed a monoallelic loss of approximately 18.5-kilobase region containing the whole MEN1 gene. Intriguingly, the 2 breakpoints were flanked by Alu repetitive elements, suggesting the contribution of Alu/Alu-mediated rearrangements (AAMR) to the whole MEN1 gene deletion. Furthermore, copy number mapping using MLPA and qPCR in combination with single nucleotide polymorphism analysis revealed copy-neutral LOH as a somatic event for parathyroid tumorigenesis. In conclusion, copy number mapping revealed a novel combination of Alu/Alu-mediated de novo germline deletion of the MEN1 gene and somatic copy-neutral LOH as a cytogenetic basis for the MEN1 pathogenesis. Moreover, subsequent in silico analysis highlighted the possible predisposition of the MEN1 gene to Alu retrotransposon-mediated genomic deletion.

Facilitating screening of Klinefelter syndrome among patients with diabetes.

Klinefelter syndrome (KS) is frequently complicated by diabetes. However, it is severely underdiagnosed due to a lack of reliable screening methods. We diagnosed two patients with KS at the Center for Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute Kitano Hospital, Osaka, Japan. By comparing the patients with 39 non-KS patients with diabetes, we propose a screening tool for KS in patients with diabetes.

Accelerated Progression of Hepatocellular Carcinoma during Immunosuppressive Therapy with Abatacept for Rheumatoid Arthritis.

Abatacept, a cytotoxic T lymphocyte antigen-4 immunoglobulin recombinant fusion protein, is an immunosuppressive agent indicated for rheumatoid arthritis. Although no significant increase in malignancy has been reported in abatacept-treated patients, whether or not abatacept accelerates tumor progression in specific cancer types remains unclear. We herein report a 66-year-old woman who showed unusually rapid progression of hepatocellular carcinoma following abatacept therapy for rheumatoid arthritis. Abatacept was speculated to have accelerated her hepatocellular carcinoma progression in the setting of her preexisting risk factors: autoimmune hepatitis and long-term methotrexate use. We propose close tumor surveillance be performed during abatacept therapy, especially for high-risk patients.

Chronic primary adrenal insufficiency after unilateral adrenonephrectomy: A case report.

RATIONALE: Unilateral adrenalectomy as part of surgical resection of renal cell carcinoma (RCC) is not thought to increase the risk of chronic adrenal insufficiency, as the contralateral adrenal gland is assumed to be capable of compensating for the lost function of the resected gland. However, recent studies have indicated that adrenalectomy might cause irreversible impairment of the adrenocortical reserve. We describe a case of chronic primary adrenal insufficiency in a 68-year-old man who previously underwent unilateral adrenonephrectomy, which was complicated by severe postoperative adrenal stress that involved cardiopulmonary disturbance and systemic infection. PATIENT CONCERNS: A 68-year-old Japanese man presented with weight loss of 6 kg over a 4-month period, and renal biopsy confirmed a diagnosis of RCC. He underwent adrenonephrectomy for the RCC, but developed postoperative septic shock because of a retroperitoneal cystic infection and ventricular fibrillation that was induced by vasospastic angina. The patient was successfully treated using antibiotics and percutaneous coronary intervention, and was subsequently discharged with no apparent complications except decreased appetite and general fatigue. However, his appetite and fatigue did not improve over time and he was readmitted for an examination. DIAGNOSES: The workup revealed a markedly elevated adrenocorticotropic hormone (ACTH) level (151.4 pg/mL, normal: 7-50 pg/mL) and a mildly decreased morning serum cortisol level (6.4 mg/mL, normal: 7-28 mg/mL). In addition to the patient's clinical symptoms and laboratory results, the results from ACTH and corticotropin-releasing hormone stimulation tests were used to make a diagnosis of primary adrenal insufficiency. INTERVENTIONS: Treatment was initiated using oral prednisolone (20 mg), which rapidly resolved his symptoms. At the 1-year follow-up, the patient had a markedly decreased serum cortisol level (2.0 mg/mL) with an ACTH level that was within the normal range (44.1 pg/mL) before his morning dose of prednisolone, which confirmed the diagnosis of chronic primary adrenal insufficiency. LESSONS: Clinicians must be aware of chronic adrenal insufficiency as a possible complication of unilateral adrenalectomy, especially when patients who underwent unilateral adrenalectomy experience severe adrenal stress.