ARMC5 controls the degradation of most Pol II subunits, and ARMC5 mutation increases neural tube defect risks in mice and humans.

BACKGROUND: Neural tube defects (NTDs) are caused by genetic and environmental factors. ARMC5 is part of a novel ubiquitin ligase specific for POLR2A, the largest subunit of RNA polymerase II (Pol II). RESULTS: We find that ARMC5 knockout mice have increased incidence of NTDs, such as spina bifida and exencephaly. Surprisingly, the absence of ARMC5 causes the accumulation of not only POLR2A but also most of the other 11 Pol II subunits, indicating that the degradation of the whole Pol II complex is compromised. The enlarged Pol II pool does not lead to generalized Pol II stalling or a generalized decrease in mRNA transcription. In neural progenitor cells, ARMC5 knockout only dysregulates 106 genes, some of which are known to be involved in neural tube development. FOLH1, critical in folate uptake and hence neural tube development, is downregulated in the knockout intestine. We also identify nine deleterious mutations in the ARMC5 gene in 511 patients with myelomeningocele, a severe form of spina bifida. These mutations impair the interaction between ARMC5 and Pol II and reduce Pol II ubiquitination. CONCLUSIONS: Mutations in ARMC5 increase the risk of NTDs in mice and humans. ARMC5 is part of an E3 controlling the degradation of all 12 subunits of Pol II under physiological conditions. The Pol II pool size might have effects on NTD pathogenesis, and some of the effects might be via the downregulation of FOLH1. Additional mechanistic work is needed to establish the causal effect of the findings on NTD pathogenesis.

ARMC5 is part of an RPB1-specific ubiquitin ligase implicated in adrenal hyperplasia.

ARMC5 is implicated in several pathological conditions, but its function remains unknown. We have previously identified CUL3 and RPB1 (the largest subunit of RNA polymerase II (Pol II) as potential ARMC5-interacting proteins. Here, we show that ARMC5, CUL3 and RBX1 form an active E3 ligase complex specific for RPB1. ARMC5, CUL3, and RBX1 formed an active E3 specific for RPB1. Armc5 deletion caused a significant reduction in RPB1 ubiquitination and an increase in an accumulation of RPB1, and hence an enlarged Pol II pool in normal tissues and organs. The compromised RPB1 degradation did not cause generalized Pol II stalling nor depressed transcription in the adrenal glands but did result in dysregulation of a subset of genes, with most upregulated. We found RPB1 to be highly expressed in the adrenal nodules from patients with primary bilateral macronodular adrenal hyperplasia (PBMAH) harboring germline ARMC5 mutations. Mutant ARMC5 had altered binding with RPB1. In summary, we discovered that wildtype ARMC5 was part of a novel RPB1-specific E3. ARMC5 mutations resulted in an enlarged Pol II pool, which dysregulated a subset of effector genes. Such an enlarged Pol II pool and gene dysregulation was correlated to adrenal hyperplasia in humans and KO mice.

Sodium-glucose cotransporter protein-2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists for type 2 diabetes: systematic review and network meta-analysis of randomised controlled trials.

OBJECTIVE: To evaluate sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists in patients with type 2 diabetes at varying cardiovascular and renal risk. DESIGN: Network meta-analysis. DATA SOURCES: Medline, Embase, and Cochrane CENTRAL up to 11 August 2020. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomised controlled trials comparing SGLT-2 inhibitors or GLP-1 receptor agonists with placebo, standard care, or other glucose lowering treatment in adults with type 2 diabetes with follow up of 24 weeks or longer. Studies were screened independently by two reviewers for eligibility, extracted data, and assessed risk of bias. MAIN OUTCOME MEASURES: Frequentist random effects network meta-analysis was carried out and GRADE (grading of recommendations assessment, development, and evaluation) used to assess evidence certainty. Results included estimated absolute effects of treatment per 1000 patients treated for five years for patients at very low risk (no cardiovascular risk factors), low risk (three or more cardiovascular risk factors), moderate risk (cardiovascular disease), high risk (chronic kidney disease), and very high risk (cardiovascular disease and kidney disease). A guideline panel provided oversight of the systematic review. RESULTS: 764 trials including 421 346 patients proved eligible. All results refer to the addition of SGLT-2 inhibitors and GLP-1 receptor agonists to existing diabetes treatment. Both classes of drugs lowered all cause mortality, cardiovascular mortality, non-fatal myocardial infarction, and kidney failure (high certainty evidence). Notable differences were found between the two agents: SGLT-2 inhibitors reduced admission to hospital for heart failure more than GLP-1 receptor agonists, and GLP-1 receptor agonists reduced non-fatal stroke more than SGLT-2 inhibitors (which appeared to have no effect). SGLT-2 inhibitors caused genital infection (high certainty), whereas GLP-1 receptor agonists might cause severe gastrointestinal events (low certainty). Low certainty evidence suggested that SGLT-2 inhibitors and GLP-1 receptor agonists might lower body weight. Little or no evidence was found for the effect of SGLT-2 inhibitors or GLP-1 receptor agonists on limb amputation, blindness, eye disease, neuropathic pain, or health related quality of life. The absolute benefits of these drugs vary substantially across patients from low to very high risk of cardiovascular and renal outcomes (eg, SGLT-2 inhibitors resulted in 3 to 40 fewer deaths in 1000 patients over five years; see interactive decision support tool (https://magicevidence.org/match-it/200820dist/#!/) for all outcomes. CONCLUSIONS: In patients with type 2 diabetes, SGLT-2 inhibitors and GLP-1 receptor agonists reduced cardiovascular and renal outcomes, with some differences in benefits and harms. Absolute benefits are determined by individual risk profiles of patients, with clear implications for clinical practice, as reflected in the BMJ Rapid Recommendations directly informed by this systematic review. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019153180.

Two monogenic disorders masquerading as one: severe congenital neutropenia with monocytosis and non-syndromic sensorineural hearing loss.

BACKGROUND: We report a large family with four successive generations, presenting with a complex phenotype of severe congenital neutropenia (SCN), partially penetrant monocytosis, and hearing loss of varying severity. METHODS: We performed whole exome sequencing to identify the causative variants. Sanger sequencing was used to perform segregation analyses on remaining family members. RESULTS: We identified and classified a pathogenic GFI1 variant and a likely pathogenic variant in MYO6 which together explain the complex phenotypes seen in this family. CONCLUSIONS: We present a case illustrating the benefits of a broad screening approach that allows identification of oligogenic determinants of complex human phenotypes which may have been missed if the screening was limited to a targeted gene panel with the assumption of a syndromic disorder. This is important for correct genetic diagnosis of families and disentangling the range and severity of phenotypes associated with high impact variants.

Exenatide corrects postprandial hyperglycaemia in young people with cystic fibrosis and impaired glucose tolerance: A randomized crossover trial.

Impaired glucose tolerance (IGT) in cystic fibrosis (CF) manifests as postprandial hyperglycaemia. Pancreatic enzyme supplementation reduces the latter; restoring incretin secretion and slowing gastric emptying. We aimed to determine the acute effect of exenatide on postprandial glycaemia in young people with CF and IGT. Six participants with CF and IGT were studied on 2 days, in a double-blind randomized crossover trial. After overnight fasting, they received exenatide 2.5 mcg or placebo (0.9% saline) subcutaneously 15 minutes before a pancake meal labelled with 13 C octanoate and pancreatic enzyme replacement. The primary outcomes, area under the curve over 240 minutes (AUC 240 ) for blood glucose (P < 0.0001) and peak blood glucose (7.65 mM ± 0.34 [mean ± SE] vs 9.53 mM ± 0.63, P < 0.0001), were markedly lower after exenatide than placebo. AUC240 for insulin, C-peptide, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) was also lower after exenatide. Gastric emptying was markedly slower after exenatide, as assessed by time for 10% gastric emptying and peak 13 CO2 excretion. We report for the first time that exenatide corrects postprandial hyperglycaemia in young people with CF and IGT. GLP-1 agonists are a candidate treatment in CF-related diabetes.

Low-dose hydrocortisone replacement improves wellbeing and pain tolerance in chronic pain patients with opioid-induced hypocortisolemic responses. A pilot randomized, placebo-controlled trial.

UNLABELLED: Long-term opioid therapy has been associated with low cortisol levels due to central suppression of the hypothalamic-pituitary-adrenal axis. The implications of hypocortisolism on wellbeing have not been established. Our aim was to determine whether intervention with physiologic glucocorticoid replacement therapy improves wellbeing and analgesic responses in patients with chronic non-cancer pain on long-term opioid therapy with mild cortisol deficiency. We performed a pilot randomized, double-blind, placebo-controlled crossover study of oral hydrocortisone replacement therapy in 17 patients recruited from a Pain Clinic at a single tertiary center in Adelaide, Australia. Patients were receiving long-term opioid therapy (≥ 20 mg morphine equivalents per day for ≥ 4 weeks) for chronic non-cancer pain with mild hypocortisolism, as defined by a plasma cortisol response ≤ 350 nmol/L at 60 min following a cold pressor test. The crossover intervention included 28-day treatment with either 10mg/m(2)/day of oral hydrocortisone in three divided doses or placebo. Improvement in wellbeing was assessed using Version 2 of the Short Form-36 (SF-36v2), Brief Pain Inventory-Short Form, and Addison's disease quality of life questionnaires; improvement in analgesic response was assessed using cold pressor threshold and tolerance times. Following treatment with hydrocortisone, the bodily pain (P=0.042) and vitality (P=0.013) subscales of the SF-36v2 were significantly better than scores following treatment with placebo. There was also an improvement in pain interference on general activity (P=0.035), mood (P=0.03) and work (P=0.04) following hydrocortisone compared with placebo. This is the first randomized, double-blind placebo-controlled trial of glucocorticoid replacement in opioid users with chronic non-cancer pain and mild hypocortisolism. Our data suggest that physiologic hydrocortisone replacement produces improvements in vitality and pain experiences in this cohort compared with placebo. TRIAL REGISTRATION: Therapeutic Goods Administration Clinical Trials Notification Scheme (Drugs), Trial Number 2012/0476.

Allan-Herndon-Dudley syndrome with unusual profound sensorineural hearing loss.

The Allan-Herndon-Dudley syndrome is caused by mutations in the thyroid hormone transporter, Monocarboxylate transporter 8 (MCT8). It is characterized by profound intellectual disability and abnormal thyroid function. We report on a patient with Allan-Herndon-Dudley syndrome (AHDS) with profound sensorineural hearing loss which is not usually a feature of AHDS and which may have been due to a coexisting nonsense mutation in Microphthalmia-associated transcription factor (MITF).

Continuous subcutaneous hydrocortisone infusion therapy in Addison's disease: a randomized, placebo-controlled clinical trial.

CONTEXT: Patients with Addison's disease (AD) report impaired subjective health status (SHS). Since cortisol exhibits a robust circadian cycle that entrains other biological clocks, impaired SHS may be due to the noncircadian cortisol profile achieved with conventional glucocorticoid replacement. Continuous subcutaneous hydrocortisone infusion (CSHI) reproduces a circadian cortisol profile, but its effects on SHS have not been objectively evaluated. OBJECTIVE: The aim of this study was to determine the effect of CSHI on SHS in AD. SETTING AND DESIGN: This was a multicentre, double-blind, placebo-controlled trial of CSHI vs oral glucocorticoid therapy. Participants received in random order 4 weeks of: CSHI and oral placebo, and subcutaneous placebo and oral hydrocortisone, separated by a 2-week washout period. SHS was assessed using the Short-Form 36 (SF-36), General Health Questionnaire (GHQ-28), Fatigue Scale (FS), Gastrointestinal Symptom Rating Scale (GSRS); and Addison's Quality of Life Questionnaire (AddiQoL). Participants were asked their (blinded) treatment preference. Twenty-four hour urine free cortisol (UFC) and diurnal salivary cortisol collections compared cortisol exposure during each treatment. RESULTS: Ten participants completed the study. Baseline SHS scores (mean ± SE) were consistent with mild impairment: SF-36 physical component summary 48.4 (± 2.4), mental component summary 53.3 (± 3.0); GHQ-28 18.1 (± 3.3); GSRS 3.7 (± 1.6), and AddiQoL 94.7 (± 3.7). FS was similar to other AD cohorts 13.5 (± 1.0) (P = 0.82). UFC between treatments was not different (P = 0.87). The salivary cortisol at 0800 h was higher during CSHI (P = 0.03), but not at any other time points measured. There was no difference between the treatments in the SHS assessments. Five participants preferred CSHI, four oral hydrocortisone, and one was uncertain. CONCLUSIONS: Biochemical measurements indicate similar cortisol exposure during each treatment period, although a more circadian pattern was evident during CSHI. CSHI does not improve SHS in AD with good baseline SHS. This casts some doubt on the potential benefit of circadian cortisol delivery on SHS in AD.

ARMC5 mutations are common in familial bilateral macronodular adrenal hyperplasia.

CONTEXT: Bilateral macronodular adrenal hyperplasia (BMAH) is a rare form of adrenal Cushing's syndrome. Familial cases have been reported, but at the time we conducted this study, the genetic basis of BMAH was unknown. Recently, germline variants of armadillo repeat containing 5 (ARMC5) in patients with isolated BMAH and somatic, second-hit mutations in tumor nodules, were identified. OBJECTIVE: Our objective was to identify the genetic basis of familial BMAH. DESIGN: We performed whole exome capture and sequencing of 2 affected individuals from each of 4 BMAH families (BMAH-01, BMAH-02, BMAH-03, and BMAH-05). Based on clinical evaluation, there were 7, 3, 3, and 4 affected individuals in these families, respectively. Sanger sequencing of ARMC5 was performed in 1 other BMAH kindred, BMAH-06. RESULTS: Exome sequencing identified novel variants Chr16:g.31477540, c.2139delT, p.(Thr715Leufs*1) (BMAH-02) and Chr16:g.31473811, c.943C→T, p.(Arg315Trp) (BMAH-03) in ARMC5 (GRch37/hg19), validated by Sanger sequencing. BMAH-01 had a recently reported mutation Chr16:g.31476121, c.1777C→T, p.(Arg593Trp). Sanger sequencing of ARMC5 in BMAH-06 identified a previously reported mutation, Chr16:g. 31473688; c.799C→T, p.(Arg267*). The genetic basis of BMAH in BMAH-05 was not identified. CONCLUSIONS: Our studies have detected ARMC5 mutations in 4 of 5 BMAH families tested, confirming that these mutations are a frequent cause of BMAH. Two of the 4 families had novel mutations, indicating allelic heterogeneity. Preclinical evaluation did not predict mutation status. The ARMC5-negative family had unusual prominent hyperaldosteronism. Further studies are needed to determine the penetrance of BMAH in ARMC5 mutation-positive relatives of affected patients, the practical utility of genetic screening and genotype-phenotype correlations.

A case of Aromatase deficiency due to a novel CYP19A1 mutation.

BACKGROUND: Aromatase deficiency is a rare, autosomal recessive disorder of which there are approximately twenty four case reports. The aromatase enzyme is crucial in the biosynthesis of oestrogens from androgens. The phenotype of aromatase deficiency therefore is the result of androgen excess and oestrogen deficiency in the absence of normal aromatase activity. We report the first case of aromatase deficiency diagnosed in a female adult, at the age of 32 years, due to a novel duplication in the aromatase gene. CASE PRESENTATION: A 32 year old Indian woman presented with a history of gender assignment difficulties at birth, lack of pubertal development, osteopaenia with fracture and tall stature. She had central obesity, impaired fasting glucose and borderline hypertension. Past examinations had revealed partial fusion of urethra and vagina, hypoplastic uterus and streak ovaries. The ovaries had been excised due to malignant risk after an initial clinical diagnosis of Turner's syndrome with Y mosaicism. Oestrogen replacement commenced shortly after her fracture, in adulthood. After reassessment, aromatase deficiency was diagnosed. Sequencing of the coding exons of the aromatase (CYP19A1; OMIM 109710) gene revealed a novel 27-base duplication in exon 8 (p.Ala306_Ser314dup). This duplication, occurring within the aromatase α-helix, would be likely to disrupt substrate (androgen) and cofactor (protoporphyrin IX) binding, resulting in a lack of oestrogen synthesis. CONCLUSIONS: We report a female with a phenotype compatible with aromatase deficiency which was unrecognised until adulthood and found she had a novel duplication in CYP19A1. Previous case reports have described polycystic ovarian morphology, especially in childhood and adolescence, but never streak ovaries. This may reflect the few adult cases reported, that aromatase deficiency in females is generally diagnosed at birth and oestrogen treatment commences decades earlier than occurred in our patient. Streak ovaries are consistent with the phenotype of the aromatase knockout mouse followed through adulthood. The observed clinical features of obesity, dysglycaemia and hypertension, are compatible with the observation that lack of a counterbalancing effect of oestrogen on tissue androgens until adulthood may lead to a metabolic syndrome phenotype. This report broadens the spectra of phenotype and genetic mutations underlying this rare disorder.

Heritable GATA2 mutations associated with familial myelodysplastic syndrome and acute myeloid leukemia.

We report the discovery of GATA2 as a new myelodysplastic syndrome (MDS)-acute myeloid leukemia (AML) predisposition gene. We found the same, previously unidentified heterozygous c.1061C>T (p.Thr354Met) missense mutation in the GATA2 transcription factor gene segregating with the multigenerational transmission of MDS-AML in three families and a GATA2 c.1063_1065delACA (p.Thr355del) mutation at an adjacent codon in a fourth MDS family. The resulting alterations reside within the second zinc finger of GATA2, which mediates DNA-binding and protein-protein interactions. We show differential effects of the mutations on the transactivation of target genes, cellular differentiation, apoptosis and global gene expression. Identification of such predisposing genes to familial forms of MDS and AML is critical for more effective diagnosis and prognosis, counseling, selection of related bone marrow transplant donors and development of therapies.

Corticosteroid-binding globulin: the clinical significance of altered levels and heritable mutations.

Corticosteroid-binding globulin (CBG) is the specific high-affinity plasma transport glycoprotein for cortisol. Stress-induced falls in CBG levels may heighten hypothalamic-pituitary-adrenal axis responses and CBG:tissue interactions may allow targeted cortisol delivery. Three genetic variants of CBG have been identified that reduce cortisol binding affinity and/or CBG levels. These include the Leuven and Lyon mutations which reduce CBG:cortisol binding affinity 3- and 4-fold, respectively, and the null mutation resulting in a 50% (heterozygote) or 100% (homozygote) reduction in CBG levels. The three reported null homozygotes demonstrate that complete CBG deficiency is not lethal, although it may be associated with hypotension and fatigue. The phenotype of a CBG null murine model included fatigue and immune defects. One community-based study revealed that severe CBG mutations are rare in idiopathic fatigue disorders. The mechanisms by which CBG mutations may cause fatigue are unknown. There are preliminary data of altered CBG levels in hypertension and in the metabolic syndrome; however, the nature of these associations is uncertain. Further studies may clarify the functions of CBG, and clinical observations may validate and/or extend the phenotypic features of various CBG mutations.

Familial vasopressin-sensitive ACTH-independent macronodular adrenal hyperplasia (VPs-AIMAH): clinical studies of three kindreds.

OBJECTIVE: Cushing's syndrome due to familial ACTH-independent macronodular adrenal hyperplasia (AIMAH) has been reported in small kindreds. In vasopressin-sensitive AIMAH (VPs-AIMAH), VP stimulates an aberrant, ACTH-independent increase in cortisol. The aims of this study were to (i) delineate the preclinical phenotype of VPs-AIMAH in a three-generation kindred (AIMAH-01) and two smaller kindreds (AIMAH-02 and AIMAH-03) and (ii) investigate the aetiology of VP sensitivity in AIMAH-01. DESIGN: Clinical studies of three kindreds for adrenal tumours or early Cushing's and molecular studies of adrenal tumours (AIMAH-01). PATIENTS: Thirty-three individuals, from three kindreds, were screened for perturbations of the hypothalamic-pituitary-adrenal axis or adrenal tumours. MEASUREMENTS: Patients underwent clinical, biochemical and adrenal imaging investigations. Evaluation included low-dose (1 IU/70 kg) VP stimulation. Adrenal VP receptor (AVPR1A, AVPR1B, AVPR2) expression (AIMAH-01) was assessed using RT-PCR and immunohistochemistry (IHC). IHC for VP was also performed. RESULTS: AIMAH-01 had three siblings with Cushing's, and four individuals with suppressed ACTH/aberrant VP responses and/or adrenal nodules. In AIMAH-02, a father and son were affected. AIMAH-03 had three siblings with Cushing's. RT-PCR showed adrenal overexpression of AVPR1A and AVPR1B. IHC detected AVPR1A. The adrenal tumour from one patient also stained weakly for VP and AVPR2. CONCLUSION: Adrenal nodules, suppressed ACTH and increased VP sensitivity may represent preclinical disease, allowing early detection, and treatment, of affected individuals. In AIMAH-01, increased VP sensitivity may be due to adrenal VP receptor overexpression. In these kindreds, VPs-AIMAH is familial, and autosomal dominant inheritance is most likely.

Management of obesity in patients with type 2 diabetes mellitus.

Type 2 Diabetes Mellitus (T2DM) is a disease of over nutrition; the onset and progression of which, is associated with excess fat accumulation in the abdomen, muscles and liver. In this review, we focus on management of obesity as the primary strategy for management of disorders of glucose metabolism. Modest weight loss (~7%) achieved by diet and exercise can prevent, or delay, the onset of T2DM. In those with established T2DM, weight loss reduces fasting and post-prandial plasma glucose levels, HbA(1c), and the need for pharmacotherapy. The beneficial effects on glucose metabolism of caloric restriction, and aerobic and resistance exercise, may occur independently of weight loss. When substantial weight loss is required, meal replacements allow a large reduction in energy consumption whilst maintaining micronutrient intake. Pharmacotherapy for obesity, as part of an integrated management plan, is useful for maintaining weight loss and optimising glycaemic control. The most effective long-term therapy for obesity remains bariatric surgery, which is associated with resolution of T2DM in over 80% of patients. The currently available pharmacotherapies for T2DM mostly result in weight gain. Pramlintide and exenatide are new therapies which hold promise, because in addition to improved glycaemic control, they also result in weight loss.