Syndromes Of Severe Insulin Resistance Research Articles

Hereditary Severe Insulin-resistance Syndrome and Acanthosis Nigricans Caused by Novel Mutations in the INSR Gene.

Most cases associated with Hereditary Severe Insulin Resistance Syndrome (H-SIRS) are linked to mutations in the insulin receptor (INSR) gene. Patients with H-SIRS typically manifest symptoms of hyperinsulinemia, insulin resistance, and diabetes mellitus. Other symptoms include impaired glucose regulation, hyperandrogenism, and the presence of acanthosis nigricans (AN). In this report, we present two cases of H-SIRS in female children exhibiting various symptoms, such as hyperinsulinemia, fasting hypoglycemia, postprandial hyperglycemia, overweight, fatty liver, hyperandrogenism, and varying degrees of AN. One patient also presented with mental retardation. Gene sequencing identified specific mutations in the INSR gene for both patients: c.2663A > G (p.Tyr888Cys) and c.38_61del (p.Pro13_Ala20del). These mutations have the potential to disrupt the interaction between INSR and insulin, leading to abnormal insulin signaling, insulin resistance, and various clinical manifestations.

Diagnostic and referral pathways in patients with rare lipodystrophy and insulin-resistance syndromes: key milestones assessed from a national reference center

BackgroundRare syndromes of lipodystrophy and insulin-resistance display heterogeneous clinical expressions. Their early recognition, diagnosis and management are required to avoid long-term complications.ObjectiveWe aimed to evaluate the patients’ age at referral to our dedicated national reference center in France and their elapsed time from first symptoms to diagnosis and access to specialized care.Patients and methodsWe analyzed data from patients with rare lipodystrophy and insulin-resistance syndromes referred to the coordinating PRISIS reference center (Adult Endocrine Department, Saint-Antoine Hospital, AP-HP, Paris), prospectively recorded between 2018 and 2023 in the French National Rare Disease Database (BNDMR, Banque Nationale de Données Maladies Rares).ResultsA cohort of 292 patients was analyzed, including 208 women, with the following diagnosis: Familial Partial LipoDystrophy (FPLD, n = 124, including n = 67 FPLD2/Dunnigan Syndrome); Acquired lipodystrophy syndromes (n = 98, with n = 13 Acquired Generalized Lipodystrophy, AGL); Symmetric cervical adenolipomatosis (n = 27, Launois-Bensaude syndrome, LB), Congenital generalized lipodystrophy (n = 18, CGL) and other rare severe insulin-resistance syndromes (n = 25). The median age at referral was 47.6 years [IQR: 31–60], ranging from 25.2 (CGL) to 62.2 years old (LB). The median age at first symptoms of 27.6 years old [IQR: 16.8–42.0]) and the median diagnostic delay of 6.4 years [IQR: 1.3–19.5] varied among diagnostic groups. The gender-specific expression of lipodystrophy is well-illustrated in the FPLD2 group (91% of women), presenting with first signs at 19.3 years [IQR: 14.4–27.8] with a diagnostic delay of 10.5 years [IQR: 1.8–27.0].ConclusionThe national rare disease database provides an important tool for assessment of care pathways in patients with lipodystrophy and rare insulin-resistance syndromes in France. Improving knowledge to reduce diagnostic delay is an important objective of the PRISIS reference center.

SGLT2 inhibitor monotherapy alleviates hyperglycemia in heredity severe insulin resistance syndrome.

SGLT2 inhibitor monotherapy alleviates hyperglycemia in heredity severe insulin resistance syndrome.

THU301 Natural History Of Pregnancy And Pregnancy Outcomes In Subjects With Lipodystrophy

Abstract Disclosure: T.J. Neal: None. M.S. Startzell: None. E. Cochran: None. M. Lightbourne: None. R.J. Brown: None. Lipodystrophy syndromes are a group of rare heterogenous disorders characterized by deficiency of adipose tissue in a regional distribution (Partial Lipodystrophy, PL) or all of the body (Generalized Lipodystrophy, GL), leading to severe insulin resistance, diabetes, hypertriglyceridemia, non-alcoholic steatohepatitis, and polycystic ovarian syndrome. During pregnancy in patients with lipodystrophy, insulin resistance worsens during late gestation, leading to pregnancy complications that may threaten the lives of the fetus and mother. Case reports have suggested increased risk of pregnancy complications such as pre-eclampsia in patients with lipodystrophy. We sought to systematically examine pregnancy complications and offspring outcomes in lipodystrophy through a prospective study involving structured interviews with patients with known lipodystrophy and past pregnancy. Data were collected in 7 patients with PL (2 LMNA, PPARG, 4 unknown genetic cause) and 1 with GL (AGPAT2). These 7 patients had 21 pregnancies (mean 2.6), including 19 singleton and 2 twin gestations. 14 pregnancies (67%) were spontaneous and 7 (33%) required fertility treatment. 10 pregnancies (48%) in 6 patients resulted in 12 live births (7 term, 3 preterm; 3 vaginal and 8 C-section delivery) and 11 (52%) resulted in miscarriage (9 first trimester, 2 second trimester in 1 patient due to cervical insufficiency). There were no episodes of acute pancreatitis during pregnancy. Among the 10 pregnancies resulting in live birth, 100% were complicated by diabetes. 5 (50%) had pre-gestational diabetes and 5 (50%) had gestational diabetes that resolved after delivery. 8 (80%) required insulin during pregnancy (of whom none required insulin pre-pregnancy). 5 (50%) of these pregnancies were complicated by pre-eclampsia. Among all 21 pregnancies, metformin was used in 8 (38%), insulin in 8 (38%), metreleptin in 4 (19%) pregnancies (all 4 of which were in 1 patient with GL), and fenofibrate in 2 (9.5%). Among 12 offspring, 1 (8%) was small for gestational age (GA), 8 (67%) were appropriate for GA and 3 (25%) were large for GA. 6 (50%) had neonatal hypoglycemia. In summary, pregnancies in women with lipodystrophy showed high complication rates, including very high rates of miscarriage, diabetes, and pre-eclampsia. Larger studies are needed to determine how management of these patients during pregnancy, including with newer treatments such as metreleptin for GL, affects pregnancy and offspring outcomes. Presentation: Thursday, June 15, 2023

189-OR: FGF21-Mediated Signaling Defects and Their Effects on Insulin Resistance in Insulin-Mediated Pseudoacromegaly

Insulin-mediated pseudoacromegaly (IMPA) is a rare, severe insulin resistance syndrome linked to digenic mutations in FGFR1 and KLB. These proteins form the receptor complex for FGF21, a hepatokine that plays a critical role in adipose tissue insulin sensitivity. Patients with IMPA have normal growth hormone and IGF-1. However, they have markedly increased insulin levels, tall stature, and obesity. To assess the pathogenicity of these mutations, we isolated iPSC from the proband with IMPA. We used CRISPR gene editing to correct the FGFR1 and KLB mutations and differentiated the iPSC lines into adipocytes. Western immunoblotting demonstrated that the uncorrected (mutant) cells demonstrated decreased levels of FGFR1 and pERK1/2 in response to insulin and/or FGF21 compared to corrected (wild-type) cells. Additionally, mutant adipocytes demonstrated significantly larger lipid droplets when stained with BODIPY. To complement the iPSC work, a humanized transgenic knock-in mouse line was created using CRISPR gene editing. When exposed to a high fat diet (HFD), female mice harboring variants in FGFR1 and KLB (DM - Double Mutant) developed significant weight gain compared to wild-type (WT) littermates. The difference in body weight was attributed to a difference in body fat. Similar to the human phenotype, the DM mice experience intermittent hyperglycemia and significant hyperinsulinemia. Explants of gonadal white adipose tissue demonstrated decreased lipolysis and pAKT and pERK. Mac-2 staining of white adipose tissue demonstrated abundant adipose tissue macrophages forming crown-like structures, suggesting adipose tissue inflammation. Additionally, we measured gene expression in brown adipose tissue, and noting that Ucp1 expression in DM mice was 37% when compared to WT. These results suggest pathogenic mechanisms in which FGFR1 and KLB mutations lead to IMPA via decreased FGF21-mediated signaling in the adipose tissue. Disclosure N.Phan: None. D.M.Ornitz: None. S.I.Stone: None. Funding Eunice Kennedy Shriver National Institute of Child Health and Human Development (R21HD098872); National Institute of Diabetes and Digestive and Kidney Diseases (K08 DK124574, P30DK020579, P30DK056341); National Center for Advancing Translational Sciences

Frequency and characteristics of diabetes in lipodystrophies and insulin receptoropathies compared with type 1 and type 2: results from the multicenter DPV registry.

To investigate the frequency, treatment, and outcome of patients with diabetes due to severe insulin resistance syndromes (SIRS). Based on data from the multicenter prospective Diabetes Registry DPV, we analyzed diagnosis, treatment, and outcome of 636,777 patients with diabetes from 1995 to 2022. Diabetes due to SIRS was documented in 67 cases (62.7% females), 25 (37%) had lipodystrophies (LD) and 42 (63%) had congenital defects of insulin signaling. The relative frequency compared to type 1 diabetes (T1D) was about 1:2300. Median age at diabetes diagnosis in patients with SIRS was 14.8 years (interquartile range (IQR) 12.8-33.8). A total of 38 patients with SIRS (57%) received insulin and 34 (51%) other antidiabetics, mostly metformin. As high as 16% of patients with LD were treated with fibrates. Three out of eight patients with generalized LD (37.5%) were treated with metreleptin and one patient with Rabson-Mendenhall syndrome was treated with recombinant insulin-like growth factor 1. The median glycated hemoglobin level at follow-up was 7.1% (54 mmol/mol). Patients with LD had higher triglycerides than patients with T1D and T2D (P < 0.001 and P = 0.022, respectively), and also significantly higher liver enzymes and lower high-density lipoprotein cholesterol than patients with T1D (P < 0.001). Patients with insulin receptor disorders were significantly less likely to be treated with antihypertensive medication than patients with T2D (P = 0.042), despite having similar levels of hypertension. Diabetes due to SIRS is rarely diagnosed and should be suspected in lean children or young adults without classical T1D. Awareness of cardiovascular risk factors in these patients should be raised.

Neonatal diabetes mellitus and polycystic ovaries in a child with severe insulin resistance caused by a variant in the INSR gene. Description of the clinical case

Rare severe insulin resistance syndromes such as Donohue syndrome, RabsonMendenhall syndrome, and type A insulin resistance are caused by mutations in the insulin receptor (INSR) gene. Donohue and RabsonMendenhall syndromes are caused by biallelic mutations in the - and / or -subunits of INSR, are characterized by a severe course with severe clinical symptoms and an unfavorable prognosis. The difficulty of managing and treating these patients is associated with a low incidence, lack of practice in managing such patients, as well as a lack of experience in surgical interventions in these patients.&#x0D; All insulin resistance syndromes are characterized by a significant increase in the level of insulin in the blood plasma in the absence of obesity, progressive diabetes mellitus and an excess of androgens. Polycystic ovary syndrome or stromal hyperthecosis develops in adult patients with syndromic forms of insulin resistance.&#x0D; We present a rare clinical case of a complicated course of Donohue syndrome, diagnosed in a 2-month-old patient. A feature of this clinical case was the giant growing multifollicular ovaries, which became an absolute indication for organ resection surgery.&#x0D; The experience of treatment and observation of this patient reflects the importance of early verification of the diagnosis, timely appointment of adequate therapy, allows you to objectively assess the effectiveness of the treatment, helps in choosing medical tactics and predicting the course and outcome of the disease.

Excess 11-Oxygenated Androgens in Women With Severe Insulin Resistance Are Mediated by Adrenal Insulin Receptor Signaling.

Syndromes of severe insulin resistance (SIR) include insulin receptoropathy, in which all signaling downstream of the insulin receptor is lost, and lipodystrophy, in which some signaling pathways are impaired and others preserved. Women with SIR commonly have ovarian hyperandrogenemia; adrenal-derived 11-oxygenated androgens, produced by CYP11B1, have not been studied. We aimed to evaluate classic pathway androgens (androstenedione, testosterone) and 11-oxygenated androgens in women with SIR and hyperandrogenemia, and to elucidate the role of insulin receptor signaling for 11-oxygenated androgen production by comparing lipodystrophy and receptoropathy. Steroid hormones were quantified using LC-MS/MS in a cross-sectional study of 18 women with hyperandrogenemia and SIR (11 lipodystrophy, 7 receptoropathy) and 23 controls. To assess ovarian vs adrenal origin, steroids were compared in receptoropathy patients with (Ovary+) vs without (Ovary-) ovarian function. Compared with controls, classic androgens were elevated in both lipodystrophy and receptoropathy, and 11-oxygenated androgens were increased in lipodystrophy (2.9-fold higher 11β-hydroxyandrostenedione (11OHA4), 2.4-fold higher 11-ketoandrostenedione (11KA4), 3.6-fold higher 11-ketotestosterone (11KT); P < 0.01), but not receptoropathy. Product-to-precursor ratios for CYP11B1 conversion of androstenedione to 11OHA4 were similar in lipodystrophy and controls but decreased in receptoropathy (6.5-fold lower than control; P = 0.001). Classic androgens were elevated in Ovary + but not Ovary- patients. 11-Oxygenated androgens are elevated in lipodystrophy but not receptoropathy. In SIR, insulin receptor signaling is necessary for adrenal hyperandrogenemia but not ovarian hyperandrogenemia; excess classic androgens are derived from the ovaries. Insulin receptor signaling increases adrenal 19-carbon steroid production, which may have implications for more common disorders of mild IR.

144-OR: Adipose Modeling of FGF21 Signaling Mutations in a Severe Insulin Resistance Syndrome

Insulin-mediated pseudoacromegaly (IMPA) is a rare, severe insulin resistance syndrome characterized by tall stature, acanthosis nigricans, obesity, and acromegalic features. Patients with IMPA have normal growth hormone and IGF-1. However, they have markedly increased insulin levels. Our group previously described a patient with IMPA who carries digenic mutations in fibroblast growth factor receptor 1 (FGFR1) and beta-klotho (KLB) , which form the receptor complex for FGF21. FGF21 is a hepatokine that plays a critical role in adipose insulin sensitivity. To assess the pathogenicity of these mutations, we isolated iPSC from the proband with IMPA. We used CRISPR gene editing to correct the FGFR1 and KLB mutations and differentiated the iPSC lines into adipocytes. Both the uncorrected (mutant) and corrected (wild-type) lines were able to undergo successful differentiation to adipocytes. Western immunoblotting demonstrated that the uncorrected cells demonstrated decreased levels of FGFR1, pERK1/2, and p38-MAPK in response to insulin and/or FGF21. Additionally, the mutant adipocytes demonstrated significantly larger lipid droplets when stained with BODIPY (mean droplet size 62.6 μm2 uncorrected; 40.8 μm2 corrected; p= 0.00016) . To complement the iPSC work, a transgenic knock-in mouse line was created using CRISPR gene editing. Explants of gonadal white adipose tissue isolated from these mice demonstrated significantly decreased lipolysis (Max NEFA in mutant 0.mEq/L; wild-type 0.13 mEq/L; p=0.003) . Additionally, qRT PCR was performed in brown adipose tissue demonstrating decreased Ucp1 expression (mutant mice 37.2% of WT; p=4.0x10-5) . These results suggest that the FGFR1 and KLB mutations lead to decreased FGF21 signaling. Mutant adipose tissues are dysfunctional with impaired lipolysis and Ucp1 expression. Therefore these models are useful for determining the role of the FGF21 signaling in human insulin resistance syndromes. Disclosure N.Phan: None. D.M.Ornitz: None. S.I.Stone: Speaker's Bureau; Rhythm Pharmaceuticals, Inc. Funding NICHD (R21 HD098872) , NIDDK (KDK124574) , NCATS (UL1TR000448) , NIDDK (P30 DK020579) , NIDDK (P30 DK056341) , Burroughs Wellcome Fund Physician-Scientist Institutional Award, and Centene Precision Medicine Initiative

Approach to androgen excess in women: Clinical and biochemical insights.

Androgen excess in women typically presents clinically with hirsutism, acne or androgenic alopecia. In the vast majority of cases, the underlying aetiology is polycystic ovary syndrome (PCOS), a common chronic condition that affects up to 10% of all women. Identification of women with non‐PCOS pathology within large cohorts of patients presenting with androgen excess represents a diagnostic challenge for the endocrinologist, and rare pathology including nonclassic congenital adrenal hyperplasia, severe insulin resistance syndromes, Cushing's disease or androgen‐secreting tumours of the ovary or adrenal gland may be missed in the absence of a pragmatic screening approach. Detailed clinical history, physical examination and biochemical phenotyping are critical in risk‐stratifying women who are at the highest risk of non‐PCOS disorders. Red flag features such as rapid onset symptoms, overt virilization, postmenopausal onset or severe biochemical disturbances should prompt investigations for underlying neoplastic pathology, including dynamic testing and imaging where appropriate. This review will outline a proposed diagnostic approach to androgen excess in women, including an introduction to androgen metabolism and provision of a suggested algorithmic strategy to identify non‐PCOS pathology according to clinical and biochemical phenotype.

Congenital insulin resistance in the practice of the pediatrician and pediatric endocrinologist -path to diagnosis

Introduction. Hyperinsulinemic hypoglycemia in children is most commonly due to congenital hyperinsulinism. When hyperinsu-linemia is accompanied by fasting hypoglycemia and postprandial hyperglycemia, rare syndromes of severe insulin resistance, which include Rabson - Mendenhall syndrome, should be suspected. This article provides an analytical review of current data on this rare genetic pathology and presents a clinical case of a previously undescribed combination of Rabson-Mendenhall syndrome with mutations in the insulin receptor gene INSR in the compound heterozygous state with multiple congenital anomalies of other organs.Clinical case. Patient N, 5.5 months old boy, with suspected congenital hyperinsulinism due to episodes of frequent severe hypoglycemia from the first day of life. At the age of 5 months, an episode of hypoglycemia up to 2.2 mmol/L was registered at an appointment with a pediatric endocrinologist. An examination was ordered, which found that against a background decrease in blood glucose to 1.9 mmol/L, C-Peptide level &gt;5000 ng/mL, insulin level &gt;300 lU/mL, cortisol - 971 nmol/L, TSH -3.88 mlU/L, free T4 - 10.53 pmol/L (10-23.2).The importance of early diagnosis of severe insulin resistance to prevent developmental disorders in children is emphasized. The issue of organizing multiple effective monitoring of a patient’s glycemia required special attention in this clinical case. Due to the features of metabolism in young children, we abandoned flash glucose monitoring systems and used a modern glucose meter with an integration program with a mobile application and the ability to generate reports for subsequent analysis as a reliable means of glycemic control.Summary. Based on the results of the genetic study in association with the clinical phenotype, age of debut, the patient was clinically diagnosed with Rabson-Mendenhall syndrome.Discussion. The paradoxical nature of glycemic fluctuations (severe fasting hypoglycemia and postprandial diabetic hyperglycemia) is quite typical for syndromes of severe insulin resistance and should draw the attention of an informed primary care physician.Conclusion. Careful attention to the symptoms of hypoglycemia, especially with a debut in the neonatal period, recurrent episodes, and the severity of the decrease in blood glycemia. If normal or elevated levels of insulin and C-peptide are detected against the background of hypoglycemia, the first thing to think about is congenital hyperinsulinism.

337-OR: Intensive Insulin Treatment in a Patient with Type A Insulin Resistance Syndrome Associated with a Novel Heterozygous Mutation of Trp1120Gly in the Insulin Receptor Gene

Background: Type A insulin resistance syndrome is a rare congenital severe insulin resistance syndrome resulting from mutations in the insulin receptor (IR) gene. We herein report a case treated with continuous subcutaneous insulin infusion (CSII) followed by insulin glargine and pioglitazone. Clinical Case: A 16 year-old girl with BMI of 19.1 kg/m2, complained of primary amenorrhea and elevated glucose for 2 years. She was diagnosed with precocious puberty at the age of 7, and treated with letrozole and triptorelin successively for 6.5 years. Hyperinsulinemia was noted but not ameliorated with metformin treatment. All the treatment was suspended for 2 years before referring to our department. Plasma glucose during OGTT showed fasting glucose was 8.4 mmol/L, and 2-hour post-load was 23.5 mmol/L. HbA1c was 10.8%. Markedly increased fasting (245μU/mL) and post-load serum insulin (628μU/mL) were observed. Next generation sequencing revealed a novel heterozygous missense mutation of Trp1120Gly in the IR gene. The patient received CSII with 0.8U/kg as the starting daily total, and titrated the dosage according to SMBG, followed by insulin glargine and pioglitazone treatment. Her glucose was well controlled, insulin glargine was down to 8U/d at the end of 3 months. Her HbA1c dropped to 7.9%, along with fasting plasma glucose (4.6mmol/L) and serum insulin (95.44μU/mL), while 2-hour postprandial glucose and insulin were still high. Her menarche occurred after one cycle of ethinylestradiol and cyproterone combo tablets. Conclusion: Improvement of glucose control with intensive insulin treatment was observed in a patient with type A insulin resistance syndrome. However, amelioration of insulin resistance was limited. No standard treatment was recommended for this rare syndrome. Thus, large-scale long-term studies assembled worldwide to optimize treatment strategy are needed. Disclosure Y. Yang: None. Z. Huang: None. G. Wei: None. Y. Li: None. W. Deng: None. Y. Li: None. Funding National Natural Science Foundation of China (82070918)

Role of insulin and insulin resistance in androgen excess disorders.

Insulin has complex effects on cell growth, metabolism and differentiation, and these effects are mediated by a cell-surface bound receptor and eventually a cascade of intracellular signaling events. Among the several metabolic and growth-promoting effects of insulin, insulin resistance is defined as an attenuated effect of insulin on glucose metabolism, primarily the limited export of blood glucose into skeletal muscle and adipose tissue. On the other hand, not all the signaling pathways and insulin-responsive tissues are equally affected, and some effects other than the metabolic actions of insulin are overexpressed. Ovaries and the adrenal glands are two examples of tissues remaining sensitive to insulin actions where insulin may contribute to increased androgen secretion. Polycystic ovary syndrome (PCOS) is the most common form of androgen excess disorder (AED), and its pathogenesis is closely associated with insulin resistance. Patients with idiopathic hirsutism also exhibit insulin resistance, albeit lower than patients with PCOS. Although it is not as evident as in PCOS, patients with congenital adrenal hyperplasia may have insulin resistance, which may be further exacerbated with glucocorticoid overtreatment and obesity. Among patients with severe insulin resistance syndromes, irrespective of the type of disease, hyperinsulinemia promotes ovarian androgen synthesis independently of gonadotropins. It is highly debated in whom and how insulin resistance should be diagnosed and treated among patients with AEDs, including PCOS. It is not suitable to administer an insulin sensitizer relying on only some mathematical models used for estimating insulin resistance. Instead, the treatment decision should be based on the constellation of the signs, symptoms and presence of obesity; acanthosis nigricans; and some laboratory abnormalities such as impaired glucose tolerance and impaired fasting glucose.

Severe insulin resistance syndromes.

Severe insulin resistance syndromes are a heterogeneous group of rare disorders characterized by profound insulin resistance, substantial metabolic abnormalities, and a variety of clinical manifestations and complications. The etiology of these syndromes may be hereditary or acquired, due to defects in insulin potency and action, cellular responsiveness to insulin, and/or aberrations in adipose tissue function or development. Over the past decades, advances in medical technology, particularly in genomic technologies and genetic analyses, have provided insights into the underlying pathophysiological pathways and facilitated the more precise identification of several of these conditions. However, the exact cellular and molecular mechanisms of insulin resistance have not yet been fully elucidated for all syndromes. Moreover, in clinical practice, many of the syndromes are often misdiagnosed or underdiagnosed. The majority of these disorders associate with an increased risk of severe complications and mortality; thus, early identification and personalized clinical management are of the essence. This Review aims to categorize severe insulin resistance syndromes by disease process, including insulin receptor defects, signaling defects, and lipodystrophies. We also highlight several complex syndromes and emphasize the need to identify patients, investigate underlying disease mechanisms, and develop specific treatment regimens.

Leptin, adiponectin, lipodystrophic and severe insulin resistance syndromes

Leptin and adiponectin are two adipokines currently used as biomarkers for diagnostic orientation and phenotyping in syndromes of lipodystrophy and severe insulin resistance. The level of these biomarkers also has an impact on the therapeutic management of the patients. These aspects, as well as our experience as a reference center, are described in this brief overview.

Two Novel Variants and One Previously Reported Variant in the Insulin Receptor Gene in Two Cases with Severe Insulin Resistance Syndrome

Donohue syndrome (DS) and Rabson-Mendenhall syndrome (RMS) are rare diseases caused by biallelic variants within the insulin receptor gene (INSR). Here, we report 2 cases: one with DS and the other with RMS. The case with DS presented with intrauterine growth retardation, nipple hypertrophy, clitoromegaly, distended abdomen, hypertrichosis, and dysmorphic features. The second case showed severe acanthosis nigricans, hyperkeratosis, and hypertrichosis. In both cases, abnormal glucose homeostasis due to severe insulin resistance was observed. The diagnosis of DS and RMS was established based on clinical characteristics, abnormal glucose homeostasis, high serum insulin levels, and determination of pathogenic variants in the INSR gene. The first case with DS has 2 novel homozygous variants, NM_000208.3, c.3122delA (p.N1041Mfs*16) and c.3419C>G (p.A1140G), and the second case with RMS has a previously reported homozygous variant NM_000208.3, c.3529+5G>A (IVS19+5G>A) in the INSR gene.

OR05-5 AZP-3404, a 9-Amino Acid Peptide Analog of Insulin-Like Growth Factor-Binding Protein 2, Reverses Insulin Resistance in Leptin-Deficient ob/ob Mice

Insulin-like growth factor-binding protein-2 (IGFBP-2), one of six highly-conserved binding proteins that modulate circulating IGF1, has significant regulatory actions on carbohydrate, lipid and bone metabolism that are independent of its IGF-1 binding role. The metabolic activity of IGFBP-2 has been localized to a short peptide sequence within its unique heparin-binding domain, HBD-1, that is able to reproduce the metabolic actions of the full IGFBP-2 on bone and fat. Through structure-activity studies of this sequence, an acylated 9-amino acid peptide, AZP-3404, with enhanced stability and pharmacokinetics, has been developed that retains the activity of IGFBP-2 on fat and bone metabolism. As IGFBP-2 treatment has also been demonstrated to improve glucose homeostasis in animal models of severe insulin resistance, including the leptin-deficient ob/ob mouse, the present study was undertaken to determine whether AZP-3404 is able to reverse insulin resistance and improve glucose homeostasis in the ob/ob mouse. Male B6.Cg-Lepob/J mice were implanted with HD-XG telemetric devices (Data Sciences International), which allows continuous, wireless monitoring of carotid blood glucose under awake, unrestrained conditions. Animals were randomly assigned to groups (n=8) receiving either saline or AZP-3404 at 1 or 3 mg/kg, b.i.d. for four weeks. The mean daily blood glucose level prior to study initiation was 507 ± 102 mg/dL. Treatment with AZP-3404 dose-dependently decreased the average daily glucose concentration, such that by day 27, glucose levels were reduced by 64 ± 29 and 100 ± 16 mg/dL in the 1 and 3 mg/kg AZP-3404-treated groups, respectively, while slightly increased by 14 ± 29 mg/dL in the vehicle-treated group. On days 7, 14, 21 and 28, following a 24-hour fast, the mice were given an intraperitoneal glucose tolerance test (IPGTT: 1g glucose/kg) to evaluate the impact of AZP-3404 on glucose disposal which is impaired in ob/ob mice. By day 28, the fasting glucose level was reduced by 8% and 20% in the 1 and 3 mg/kg AZP-3404-treated groups, respectively, as compared with fasting levels on day 7. The IPGTTs revealed a progressive, dose-dependent reduction in glucose excursion that reached a decrease of 40% after 4 weeks of treatment with 3mg/kg AZP-3404. In related studies, we have observed that AZP-3404, both alone and in an additive manner with insulin, stimulates glucose transport in mouse C2C12 differentiated myotubes through activation of AMP-activated protein kinase (AMPK). These findings suggest that AZP- 3404 stimulates glucose uptake by muscle tissue in ob/ob mice thereby improving glucose homeostasis. The results from these studies confirm that AZP-3404 retains the ability of IGFBP-2 to restore glucose homeostasis and support the development of AZP-3404 as a novel therapeutic approach for syndromes of severe insulin resistance.

A case of insulin antibody-mediated insulin resistance in type 2 diabetes treated by glucocorticoid

The syndromes of severe insulin resistance (IR), although rare, are very interesting and clinically important. It causes a deterioration of the glycemic control, despite the very high dose of insulin. One of the rarest etiologies is autoimmunity especially the production of insulin autoantibody. We report the case of a 61-year-old woman with a history of type 2 diabetes for 10 years. She has reported a deterioration of her glycemic control despite an increase in the dose of insulin up to 200U/day (d). The clinical examination was without particularity. There was no history of drug intake. A high titer of insulin antibodies was detected in the serum 77.6%. Prednisolone was administered with a dose of 0,5mg/Kg/d for 1month. The dosage was tapered 5mg at 15 days intervals until 5mg/d. Insulin requirement decreased by 66% and glycemic control was reached. The treatment of antibody-mediated IR is not standardized; corticosteroid therapy often gives good results.

Severe insulin resistance: pathologies

AbstractIn parallel with the increasing prevalence of obesity, rates of insulin resistance and its associated complications have increased; however, insulin resistance is not only a disease of the overweight and obese. Disorders of adipose tissue expandability and insulin receptor signalling cause syndromes of severe insulin resistance that may go unrecognised in clinical practice but whose metabolic complications are significant and often the initial presentation of the condition.This review will discuss the differing pathologies mediating insulin resistance that may be seen in clinical practice and will outline the phenotypic characteristics that may allow their differentiation. Copyright © 2017 John Wiley &amp; Sons.

A Case Report of a Chinese Familial Partial Lipodystrophic Patient with Lamin A/C Gene R482Q Mutation and Polycystic Ovary Syndrome

Individuals with Familial partial lipodystrophy (FPLD), Dunnigan variety is a rare autosomal dominant disorder caused by missense mutations in Lamin gene are predisposed to insulin resistance and its complications including features of polycystic ovarian syndrome. We present a single case report about a 26-year-old Chinese woman consulted for infertility. On physical examination acanthosis nigricans and central distribution of fat were found. Her masculine type morphology, muscular appearance of the limbs and excess fat deposits in the face and neck promote us to suspect the existence of partial lipodystrophy. Biochemistry testing confirmed glucose intolerance associated with a severe insulin resistance, hypertriglyceridemia, and polycystic ovary syndrome. The detection of a heterozygous missense mutation in LAMIN A/C gene at position 482 confirmed the diagnosis of FPLD2. In conclusion, characteristic features of FPLD and mutation screening allow early diagnosis of this disorder, and facilitate appropriate clinical treatment.