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

BACKGROUND

Rare syndromes of lipodystrophy and insulin-resistance display heterogeneous clinical expressions. Their early recognition, diagnosis and management are required to avoid long-term complications.

OBJECTIVE

We 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 METHODS

We 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).

RESULTS

A 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].

CONCLUSION

The 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.

Biological markers of adipose tissue: Adipokines

We currently have a large sum of clinical and experimental data documenting the involvement of numerous adipokines in the maintenance of energy homeostasis in healthy individuals and their dysregulation in diseases such as obesity, metabolic syndrome or type 2 diabetes. Despite the impressive discoveries made in this field over many years, much remains to be done before understanding all the physiological and pathological implications, and hoping for the development of other effective and safe therapeutic strategies. Two original adipokines will be taken as examples to illustrate these remarks, chemerin and neuregulin 4.

Epigenetic/circadian clocks and PCOS

Polycystic ovary syndrome (PCOS) affects 6-20% of reproductive-aged women. It is associated with increased risks of metabolic syndrome, Type 2 diabetes, cardiovascular diseases, mood disorders, endometrial cancer and non-alcoholic fatty liver disease. Although various susceptibility loci have been identified through genetic studies, they account for ∼10% of PCOS heritability. Therefore, the etiology of PCOS remains unclear. This review explores the role of epigenetic changes and modifications in circadian clock genes as potential contributors to PCOS pathogenesis. Epigenetic alterations, such as DNA methylation, histone modifications, and non-coding RNA changes, have been described in diseases related to PCOS, such as diabetes, cardiovascular diseases, and obesity. Furthermore, several animal models have illustrated a link between prenatal exposure to androgens or anti-Müllerian hormone and PCOS-like phenotypes in subsequent generations, illustrating an epigenetic programming in PCOS. In humans, epigenetic changes have been reported in peripheral blood mononuclear cells (PBMC), adipose tissue, granulosa cells (GC), and liver from women with PCOS. The genome of women with PCOS is globally hypomethylated compared to healthy controls. However, specific hypomethylated or hypermethylated genes have been reported in the different tissues of these women. They are mainly involved in hormonal regulation and inflammatory pathways, as well as lipid and glucose metabolism. Additionally, sleep disorders are present in women with PCOS and disruptions in clock genes' expression patterns have been observed in their PBMC or GCs. While epigenetic changes hold promise as diagnostic biomarkers, the current challenge lies in distinguishing whether these changes are causes or consequences of PCOS. Targeting epigenetic modifications potentially opens avenues for precision medicine in PCOS, including lifestyle interventions and drug therapies. However, data are still lacking in large cohorts of well-characterized PCOS phenotypes. In conclusion, understanding the interplay between genetics, epigenetics, and circadian rhythms may provide valuable insights for early diagnosis and therapeutic strategies in PCOS in the future.

Proceedings of the annual meeting of the European Consortium of Lipodystrophies (ECLip), Pisa, Italy, 28-29 September 2023

Lipodystrophy syndromes are rare diseases primarily affecting the development or maintenance of the adipose tissue but are also distressing indirectly multiple organs and tissues, often leading to reduced life expectancy and quality of life. Lipodystrophy syndromes are multifaceted disorders caused by genetic mutations or autoimmunity in the vast majority of cases. While many subtypes are now recognized and classified, the disease remains remarkably underdiagnosed. The European Consortium of Lipodystrophies (ECLip) was founded in 2014 as a non-profit network of European centers of excellence working in the field of lipodystrophies aiming at promoting international collaborations to increase basic scientific understanding and clinical management of these syndromes. The network has developed a European Patient Registry as a collaborative research platform for consortium members. ECLip and ECLip registry activities involve patient advocacy groups to increase public awareness and to seek advice on research activities relevant from the patients perspective. The annual ECLip congress provides updates on the research results of various network groups members.

Adipocyte Glucocorticoid Receptor Activation With High Glucocorticoid Doses Impairs Healthy Adipose Tissue Expansion by Repressing Angiogenesis

In humans, glucocorticoids (GCs) are commonly prescribed because of their anti-inflammatory and immunosuppressive properties. However, high doses of GCs often lead to side effects, including diabetes and lipodystrophy. We recently reported that adipocyte glucocorticoid receptor (GR)-deficient (AdipoGR-KO) mice under corticosterone (CORT) treatment exhibited a massive adipose tissue (AT) expansion associated with a paradoxical improvement of metabolic health compared with control mice. However, whether GR may control adipose development remains unclear. Here, we show a specific induction of hypoxia-inducible factor 1α (HIF-1α) and proangiogenic vascular endothelial growth factor A (VEGFA) expression in GR-deficient adipocytes of AdipoGR-KO mice compared with control mice, together with an increased adipose vascular network, as assessed by three-dimensional imaging. GR activation reduced HIF-1α recruitment to the Vegfa promoter resulting from Hif-1α downregulation at the transcriptional and posttranslational levels. Importantly, in CORT-treated AdipoGR-KO mice, the blockade of VEGFA by a soluble decoy receptor prevented AT expansion and the healthy metabolic phenotype. Finally, in subcutaneous AT from patients with Cushing syndrome, higher VEGFA expression was associated with a better metabolic profile. Collectively, these results highlight that adipocyte GR negatively controls AT expansion and metabolic health through the downregulation of the major angiogenic effector VEGFA and inhibition of vascular network development.

ARTICLE HIGHLIGHTS

Prognostic impact of hypothalamic perforation in adult patients with craniopharyngioma: a cohort study

CONTEXT

Outcome of craniopharyngioma is related to its locoregional extension, which impacts resectability and the risk of surgical complications. To maximize resection and minimize complications, optic tract localization, temporal lobe extension and hypothalamic involvement are essential for surgical management.

OBJECTIVE

To assess the outcome of craniopharyngiomas depending on their relation to the hypothalamus location.

METHODS

We conducted a retrospective analysis of 79 patients with a craniopharyngioma who underwent surgery from 2007 to 2022. Craniopharyngiomas were classified in three groups, depending on the type of hypothalamus involvement assessed by preoperative MRI: infra-hypothalamic (type A, n=33); perforating the hypothalamus (type B, n=40); supra-hypothalamic (type C, n=6). Surgical strategy was guided by the type of hypothalamic involvement, favoring endonasal approaches for type A and type B, and transcranial approaches for type C.

RESULTS

Long-term disease control was achieved in 33/33 (100%), 37/40 (92%) and 5/6 (83%) patients in type A, B and C respectively. In type B, vision was improved in 32/36 (89%) patients, while hypothalamic function was improved, stable or worsened in 6/40 (15%), 32/40 (80%) and 2/40 (5%) patients respectively. Papillary craniopharyngiomas were found in 5/33 (15%), 9/40 (22%) and 3/6 (50%) patients in types A, B and C respectively. In four patients, BRAF/MEK inhibitors were used, with significant tumor shrinkage in all cases.

CONCLUSION

Craniopharyngiomas located below the hypothalamus or perforating it can be safely treated by transsphenoidal surgery. For supra-hypothalamic craniopharyngiomas, postoperative results are less favorable, and documenting a BRAF-mutation may improve outcome, if targeted therapy was efficient enough to replace surgical debulking.

Patients' perspective on the medical pathway from first symptoms to diagnosis in genetic lipodystrophy

OBJECTIVE

Underdiagnosis is an important issue in genetic lipodystrophies, which are rare diseases with metabolic, cardiovascular, gynecological, and psychological complications. We aimed to characterize the diagnostic pathway in these diseases from the patients' perspective.

DESIGN

Cross-sectional study conducted through a self-reported patient questionnaire.

METHODS

Patients with genetic lipodystrophy were recruited throughout the French national reference network for rare diseases of insulin secretion and insulin sensitivity. Patients completed a self-reported questionnaire on disease symptoms, steps leading to the diagnosis, and healthcare professionals involved. Descriptive analyses were conducted.

RESULTS

Out of 175 eligible patients, 109 patients (84% women) were included; 93 had partial familial lipodystrophy and 16 congenital generalized lipodystrophy. Metabolic comorbidities (diabetes 68%, hypertriglyceridemia 66%, hepatic steatosis 57%), cardiovascular (hypertension 54%), and gynecologic complications (irregular menstruation 60%) were frequently reported. Median age at diagnosis was 30 years (interquartile range [IQR] 23-47). The overall diagnostic process was perceived as "very difficult" for many patients. It extended over 12 years (IQR 5-25) with more than five different physicians consulted by 36% of respondents, before diagnosis, for lipodystrophy-related symptoms. The endocrinologist made the diagnosis for 77% of the patients. Changes in morphotype were reported as the first symptoms by the majority of respondents.

CONCLUSIONS

Diagnostic pathway in patients with genetic lipodystrophy is rendered difficult by the multisystemic features of the disease and the lack of knowledge of non-specialized physicians. Training physicians to systematically include adipose tissue examination in routine clinical evaluation should improve diagnosis and management of lipodystrophy and lipodystrophy-associated comorbidities.

Pituitary surgery outcome in patients 75 years and older: a retrospective study

BACKGROUND

As the population ages, the number of elderly patients with an indication for pituitary surgery is rising. Information on the outcome of patients aged over 75 is limited. This study reports a large series assessing the feasibility of surgical resection in this specific age range, focusing on surgical complications and postoperative results.

METHODS

A retrospective cohort study of patients with pituitary adenomas and Rathke's cleft cysts was conducted. All patients were aged 75 years or over and treated by a single expert neurosurgical team. A control population included 2379 younger adult patients operated by the same surgeons during the same period.

RESULTS

Between 2008 and 2022, 155 patients underwent surgery. Indication was based on vision impairment in most patients (79%). Median follow-up was 13 months (range: 3-96). The first surgery was performed with an endoscopic transsellar approach, an extended endonasal transtuberculum approach and a microscopic transcranial approach in 96%, 3%, and 1% of patients, respectively. Single surgery was sufficient to obtain volume control in 97% of patients. From Kaplan-Meier estimates, 2-year and 5-year disease control with a single surgery were 97.3% and 86.2%, respectively. Resection higher than 80% was achieved in 77% of patients. No vision worsening occurred. In acromegaly and Cushing's disease, endocrine remission was obtained in 90% of non-invasive adenomas. Surgical complications were noted in 5% of patients, with 30-day mortality, hematoma, cerebrospinal fluid leak, meningitis, and epistaxis occurring in 0.6%, 0.6%, 1.9%, 0.6%, and 1.3% respectively. New endocrine anterior deficits occurred in only 5%, while no persistent diabetes insipidus was noted. Compared with younger patients, the complication rate was not statistically different.

CONCLUSIONS

Surgery beyond the age of 75, mainly relying on an endoscopic endonasal transsellar approach, is effective and safe, provided that patients are managed in tertiary centers.

[Evolution of the non-insulin therapeutic strategy in type 2 diabetes]

While the prevalence of diabetes continues to rise worldwide, with 537 million adults aged 20-79-years-old having diabetes in 2021, the development of new therapeutic classes improving not only glycemic control but also kidney function and cardiovascular prevention has revolutionized patient care. Today, the treatment of diabetes is no longer just the treatment of blood sugar level. In this context, the individualized therapeutic strategy has been completely reviewed, with in particular sulfamides indicated much later in the therapeutic strategy, while SGLT2 inhibitors are indicated very early in patients with kidney disease and/or with ischemic heart disease or chronic heart failure, and GLP-1 analogues in obese patients and/or in primary or secondary cardiovascular prevention. As for lifestyle rules and metformin, they remain the cornerstone of treatment. Knowledge of antidiabetic effects in terms of efficacy and hypoglycemic risk, of cardiovascular, nephroprotective and weight effects is essential to optimize the management of diabetic patients today.

Second international consensus report on gaps and opportunities for the clinical translation of precision diabetes medicine

Precision medicine is part of the logical evolution of contemporary evidence-based medicine that seeks to reduce errors and optimize outcomes when making medical decisions and health recommendations. Diabetes affects hundreds of millions of people worldwide, many of whom will develop life-threatening complications and die prematurely. Precision medicine can potentially address this enormous problem by accounting for heterogeneity in the etiology, clinical presentation and pathogenesis of common forms of diabetes and risks of complications. This second international consensus report on precision diabetes medicine summarizes the findings from a systematic evidence review across the key pillars of precision medicine (prevention, diagnosis, treatment, prognosis) in four recognized forms of diabetes (monogenic, gestational, type 1, type 2). These reviews address key questions about the translation of precision medicine research into practice. Although not complete, owing to the vast literature on this topic, they revealed opportunities for the immediate or near-term clinical implementation of precision diabetes medicine; furthermore, we expose important gaps in knowledge, focusing on the need to obtain new clinically relevant evidence. Gaps include the need for common standards for clinical readiness, including consideration of cost-effectiveness, health equity, predictive accuracy, liability and accessibility. Key milestones are outlined for the broad clinical implementation of precision diabetes medicine.

Perinatal, metabolic, and reproductive features in PPARG-related lipodystrophy

OBJECTIVE

The adipogenic PPARG-encoded PPARγ nuclear receptor also displays essential placental functions. We evaluated the metabolic, reproductive, and perinatal features of patients with PPARG-related lipodystrophy.

METHODS

Current and retrospective data were collected in patients referred to a National Rare Diseases Reference Centre.

RESULTS

26 patients from 15 unrelated families were studied (18 women, median age 43 years). They carried monoallelic PPARG variants except a homozygous patient with congenital generalized lipodystrophy. Among heterozygous patients aged 16 or more (n = 24), 92% had diabetes, 96% partial lipodystrophy (median age at diagnosis 24 and 37 years), 78% hypertriglyceridaemia, 71% liver steatosis, and 58% hypertension. The mean BMI was 26 ± 5.0 kg/m2. Women (n = 16) were frequently affected by acute pancreatitis (n = 6) and/or polycystic ovary syndrome (n = 12). Eleven women obtained one or several pregnancies, all complicated by diabetes (n = 8), hypertension (n = 4), and/or hypertriglyceridaemia (n = 10). We analysed perinatal data of patients according to the presence (n = 8) or absence (n = 9) of a maternal dysmetabolic environment. The median gestational age at birth was low in both groups (37 and 36 weeks of amenorrhea, respectively). As expected, the birth weight was higher in patients exposed to a foetal dysmetabolic environment of maternal origin. In contrast, 85.7% of non-exposed patients, in whom the variant is, or is very likely to be, paternally-inherited, were small for gestational age.

CONCLUSIONS

Lipodystrophy-related PPARG variants induce early metabolic complications. Our results suggest that placental expression of PPARG pathogenic variants carried by affected foetuses could impair prenatal growth and parturition. This justifies careful pregnancy monitoring in affected families.

Proceedings of the annual meeting of the European Consortium of Lipodystrophies (ECLip) Cambridge, UK, 7-8 April 2022

Lipodystrophy syndromes are rare diseases with defects in the development or maintenance of adipose tissue, frequently leading to severe metabolic complications. They may be genetic or acquired, with variable clinical forms, and are largely underdiagnosed. The European Consortium of Lipodystrophies, ECLip, is a fully functional non-profit network of European centers of excellence working in the field of lipodystrophies. It provides a favorable environment to promote large Europe-wide and international collaborations to increase the basic scientific understanding and clinical management of these diseases. It works with patient advocacy groups to increase public awareness. The network also promotes a European Patient Registry of lipodystrophies, as a collaborative research platform for consortium members. The annual congress organized gives an update of the findings of network research groups, highlighting clinical and fundamental aspects. The talks presented during the meeting in Cambridge, UK, in 2022 are summarized in these minutes.

OR12-3 Identification of Predictive Criteria for the Primary Bilateral Macronodular Adrenal Hyperplasia Gene ARMC5: A European Series of 352 Unselected Patients

Objective

Primary Bilateral Macronodular Adrenal Hyperplasia (PBMAH) is a heterogeneous disease characterized by adrenal macronodules and variable levels of cortisol excess, with not clearly established clinical diagnostic criteria. PBMAH can be caused by germline inactivating variants of the tumor suppressor gene ARMC5. We aimed to better characterize ARMC5-mutated and wild-type patients and to identify predictive criteria for ARMC5 variants.

Methods

We included 352 consecutive index patients from 12 European centers, sequenced for germline ARMC5alteration because of PBMAH suspicion, regardless their clinical presentation. Clinical, biological and imaging data were collected retrospectively. Sensitivity, specificity, negative and positive predictive values for the prediction of ARMC5variant were calculated for various parameters.

Results

53 patients (15.1%) carried 40 different ARMC5 germline pathogenic variants and showed a more distinct phenotype than non-mutated patients for cortisol excess (24-hour urinary free cortisol 2.32 vs. 1.11-fold ULN, respectively, p<0.001; plasma cortisol after 1 mg dexamethasone suppression test 337.5 vs. 142.4 nmol/L, respectively, p<0.001) and adrenal morphology (maximal adrenal diameter 104 vs. 83 mm, respectively, p<0.001; 9.8 vs. 3.2 adrenal nodules, respectively, p<0.001), with more frequent metabolic complications such as diabetes (51.0 vs. 35.4%, respectively, p=0.038) and hypertension (88.0 vs. 70.6%, respectively, p=0.014). Thus, ARMC5-mutated patients were more often surgically or medically treated in order to control cortisol excess (67.9 vs. 36.8%, respectively, p<0.001). Among operated patients, a bilateral adrenalectomy was more often performed in those carrying an ARMC5 pathogenic variant than in wild-type patients (56.7 vs. 32.3%, respectively, p=0.019). Even if all patients were more often primarily investigated in front of adrenal incidentaloma than clinical evidence for Cushing's syndrome (73 vs. 27%, respectively), ARMC5 patients were more often referred for Cushing's syndrome than wild-type patients (44 vs. 24%, respectively, p=0.004). To improve the ARMC5 mutation rate, the association of a clear bilateral adrenal involvement with evidence for autonomous cortisol secretion (defined at least by a plasma cortisol after 1 mg dexamethasone suppression test above 50 nmol/L) holds the better yield with a 27% specificity and a 20% positive predictive value, and a 100% sensitivity and negative predictive value, meaning that a useless genotyping could have been avoided for more than 20% of negative patients, without missing any mutated patient.

Conclusion

We report the largest series of index case patients investigated for ARMC5 with clinical characterization and confirm that ARMC5 pathogenic variants are associated with a more severe phenotype. In order to minimize negative ARMC5 screening, genotyping could be limited to clear bilateral adrenal involvement on imaging and autonomous cortisol secretion, with an optimum yield for routine clinical practice. These findings will also help better define PBMAH diagnostic criteria.

Presentation: Sunday, June 12, 2022 11:30 a.m. - 11:45 a.m.

Impact of diabetes on COVID-19 prognosis beyond comorbidity burden: the CORONADO initiative

AIMS/HYPOTHESIS

Diabetes has been recognised as a pejorative prognostic factor in coronavirus disease 2019 (COVID-19). Since diabetes is typically a disease of advanced age, it remains unclear whether diabetes remains a COVID-19 risk factor beyond advanced age and associated comorbidities. We designed a cohort study that considered age and comorbidities to address this question.

METHODS

The Coronavirus SARS-CoV-2 and Diabetes Outcomes (CORONADO) initiative is a French, multicentric, cohort study of individuals with (exposed) and without diabetes (non-exposed) admitted to hospital with COVID-19, with a 1:1 matching on sex, age (±5 years), centre and admission date (10 March 2020 to 10 April 2020). Comorbidity burden was assessed by calculating the updated Charlson comorbidity index (uCCi). A predefined composite primary endpoint combining death and/or invasive mechanical ventilation (IMV), as well as these two components separately, was assessed within 7 and 28 days following hospital admission. We performed multivariable analyses to compare clinical outcomes between patients with and without diabetes.

RESULTS

A total of 2210 pairs of participants (diabetes/no-diabetes) were matched on age (mean±SD 69.4±13.2/69.5±13.2 years) and sex (36.3% women). The uCCi was higher in individuals with diabetes. In unadjusted analysis, the primary composite endpoint occurred more frequently in the diabetes group by day 7 (29.0% vs 21.6% in the no-diabetes group; HR 1.43 [95% CI 1.19, 1.72], p<0.001). After multiple adjustments for age, BMI, uCCi, clinical (time between onset of COVID-19 symptoms and dyspnoea) and biological variables (eGFR, aspartate aminotransferase, white cell count, platelet count, C-reactive protein) on admission to hospital, diabetes remained associated with a higher risk of primary composite endpoint within 7 days (adjusted HR 1.42 [95% CI 1.17, 1.72], p<0.001) and 28 days (adjusted HR 1.30 [95% CI 1.09, 1.55], p=0.003), compared with individuals without diabetes. Using the same adjustment model, diabetes was associated with the risk of IMV, but not with risk of death, within 28 days of admission to hospital.

CONCLUSIONS/INTERPRETATION

Our results demonstrate that diabetes status was associated with a deleterious COVID-19 prognosis irrespective of age and comorbidity status.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04324736.

Therapeutic indications and metabolic effects of metreleptin in patients with lipodystrophy syndromes: Real-life experience from a national reference network

AIM

To describe baseline characteristics and follow-up data in patients with lipodystrophy syndromes treated with metreleptin in a national reference network, in a real-life setting.

PATIENTS AND METHODS

Clinical and metabolic data from patients receiving metreleptin in France were retrospectively collected, at baseline, at 1 year and at the latest follow-up during treatment.

RESULTS

Forty-seven patients with lipodystrophy including generalized lipodystrophy (GLD; n = 28) and partial lipodystrophy (PLD; n = 19) received metreleptin over the last decade. At baseline, the median (interquartile range [IQR]) patient age was 29.3 (16.6-47.6) years, body mass index was 23.8 (21.2-25.7) kg/m² and serum leptin was 3.2 (1.0-4.9) ng/mL, 94% of patients had diabetes (66% insulin-treated), 53% had hypertension and 87% had dyslipidaemia. Metreleptin therapy, administered for a median (IQR) of 31.7 (14.2-76.0) months, was ongoing in 77% of patients at the latest follow-up. In patients with GLD, glycated haemoglobin (HbA1c) and fasting triglyceride levels significantly decreased from baseline to 1 year of metreleptin treatment, from 8.4 (6.5-9.9)% [68 (48-85) mmol/mol] to 6.8 (5.6-7.4)% [51(38-57) mmol/mol], and 3.6 (1.7-8.5) mmol/L to 2.2 (1.1-3.7) mmol/L, respectively (P < 0.001), with sustained efficacy thereafter. In patients with PLD, HbA1c was not significantly modified (7.7 [7.1-9.1]% [61 (54-76) mmol/mol] at baseline vs. 7.7 [7.4-9.5]% [61(57-80) mmol/mol] at 1 year), and the decrease in fasting triglycerides (from 3.3 [1.9-9.9] mmol/L to 2.5 [1.6-5.3] mmol/L; P < 0.01) was not confirmed at the latest assessment (5.2 [2.2-11.3] mmol/L). However, among PLD patients, at 1 year, 61% were responders regarding glucose homeostasis, with lower baseline leptin levels compared to nonresponders, and 61% were responders regarding triglyceridaemia. Liver enzymes significantly decreased only in the GLD group.

CONCLUSIONS

In this real-life setting study, metabolic outcomes are improved by metreleptin therapy in patients with GLD. The therapeutic indication for metreleptin needs to be clarified in patients with PLD.

Identification of predictive criteria for pathogenic variants of primary bilateral macronodular adrenal hyperplasia (PBMAH) gene ARMC5 in 352 unselected patients

OBJECTIVE

Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a heterogeneous disease characterized by adrenal macronodules and variable levels of cortisol excess, with not clearly established clinical diagnostic criteria. It can be caused by ARMC5 germline pathogenic variants. In this study, we aimed to identify predictive criteria for ARMC5 variants.

METHODS

We included 352 consecutive index patients from 12 European centers, sequenced for germline ARMC5 alteration. Clinical, biological and imaging data were collected retrospectively.

RESULTS

52 patients (14.8%) carried ARMC5 germline pathogenic variants and showed a more distinct phenotype than non-mutated patients for cortisol excess (24-h urinary free cortisol 2.32 vs 1.11-fold ULN, respectively, P < 0.001) and adrenal morphology (maximal adrenal diameter 104 vs 83 mm, respectively, P < 0.001) and were more often surgically or medically treated (67.9 vs 36.8%, respectively, P < 0.001). ARMC5-mutated patients showed a constant, bilateral adrenal involvement and at least a possible autonomous cortisol secretion (defined by a plasma cortisol after 1 mg dexamethasone suppression above 50 nmol/L), while these criteria were not systematic in WT patients (78.3%). The association of these two criteria holds a 100% sensitivity and a 100% negative predictive value for ARMC5 pathogenic variant.

CONCLUSION

We report the largest series of index patients investigated for ARMC5 and confirm that ARMC5 pathogenic variants are associated with a more severe phenotype in most cases. To minimize negative ARMC5 screening, genotyping should be limited to clear bilateral adrenal involvement and autonomous cortisol secretion, with an optimum sensitivity for routine clinical practice. These findings will also help to better define PBMAH diagnostic criteria.

Dunnigan lipodystrophy syndrome: French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins)

Dunnigan syndrome, or Familial Partial Lipodystrophy type 2 (FPLD2; ORPHA 2348), is a rare autosomal dominant disorder due to pathogenic variants of the LMNA gene. The objective of the French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins), is to provide health professionals with a guide to optimal management and care of patients with FPLD2, based on a critical literature review and multidisciplinary expert consensus. The PNDS, written by members of the French National Reference Center for Rare Diseases of Insulin Secretion and Insulin Sensitivity (PRISIS), is available on the French Health Authority website (in French). Dunnigan syndrome is characterized by a partial atrophy of the subcutaneous adipose tissue and by an insulin resistance syndrome, associated with a risk of metabolic, cardiovascular and muscular complications. Its prevalence, assessed at 1/100.000 in Europe, is probably considerably underestimated. Thorough clinical examination is key to diagnosis. Biochemical testing frequently shows hyperinsulinemia, abnormal glucose tolerance and hypertriglyceridemia. Elevated hepatic transaminases (hepatic steatosis) and creatine phosphokinase, and hyperandrogenism in women, are common. Molecular analysis of the LMNA gene confirms diagnosis and allows for family investigations. Regular screening and multidisciplinary monitoring of the associated complications are necessary. Diabetes frequently develops from puberty onwards. Hypertriglyceridemia may lead to acute pancreatitis. Early atherosclerosis and cardiomyopathy should be monitored. In women, polycystic ovary syndrome is common. Overall, the management of patients with Dunnigan syndrome requires the collaboration of several health care providers. The attending physician, in conjunction with the national care network, will ensure that the patient receives optimal care through regular follow-up and screening. The various elements of this PNDS are described to provide such a support.

A recurrent familial partial lipodystrophy due to a monoallelic or biallelic LMNA founder variant highlights the multifaceted cardiac manifestations of metabolic laminopathies

AIMS

LMNA-linked familial partial lipodystrophy type 2 (FPLD2) leads to insulin resistance-associated metabolic complications and cardiovascular diseases. We aimed to characterise the disease phenotype in a cohort of patients carrying an LMNA founder variant.

METHODS

We collected clinical and biological data from patients carrying the monoallelic or biallelic LMNA p.(Thr655Asnfs*49) variant (n = 65 and 13, respectively) and 19 non-affected relative controls followed-up in Reunion Island Lipodystrophy Competence Centre, France.

RESULTS

Two-thirds of patients with FPLD2 (n = 51) and one-third of controls (n = 6) displayed lipodystrophy and/or lean or android morphotype (P = 0.02). Although age and BMI were not statistically different between the two groups, the insulin resistance index (median HOMA-IR: 3.7 vs 1.5, P = 0.001), and the prevalence of diabetes, dyslipidaemia, and non-alcoholic fatty liver disease were much higher in patients with FPLD2 (51.3 vs 15.8%, 83.3 vs 42.1%, and 83.1 vs 33.3% (all P ≤ 0.01), respectively). Atherosclerosis tended to be more frequent in patients with FPLD2 (P = 0.07). Compared to heterozygous, homozygous patients displayed more severe lipoatrophy and metabolic alterations (lower BMI, fat mass, leptin and adiponectin, and higher triglycerides P ≤ 0.03) and tended to develop diabetes more frequently, and earlier (P = 0.09). Dilated cardiomyopathy and/or rhythm/conduction disturbances were the hallmark of the disease in homozygous patients, leading to death in four cases.

CONCLUSIONS

The level of expression of the LMNA 'Reunionese' variant determines the severity of both lipoatrophy and metabolic complications. It also modulates the cardiac phenotype, from atherosclerosis to severe cardiomyopathy, highlighting the need for careful cardiac follow-up in affected patients.

Lessons from the impact of COVID-19 on medical educational continuity and practices

The COVID-19 crisis necessitated abrupt transition to remote learning in medical schools. We aimed to assess the impact of COVID-19 on French undergraduate students and teachers, to identify practice changes, and to evaluate successes and areas for improvement of this remote learning experience. Data from 2 online questionnaires were analyzed with 509 participants among students and 189 among teachers from Sorbonne University. Responses to multiple choice, Likert response scale, and open-ended questions were evaluated. COVID-19 had negative impact on teaching continuity. Sixty-seven percent of students were in a dropout situation, and many suffered from psychological stress, leading to set up of a psychological support unit. Although most teachers (81%) and students (72%) had limited knowledge of digital resources, distance learning was quickly implemented, with a predominant use of Zoom. The analysis of several parameters revealed that students were significantly more satisfied than teachers by remote learning. Nevertheless, both students and teachers agreed to replace classical lectures by digital media and to promote in-person teaching in small interactive groups. This paper shares tips for faculty rapidly establishing remote learning. This comparative study of the students' and teachers' points of view underlines that new medical curricula should include more digital contents. We make recommendations regarding general university organization, equipment, and curricular development for long-term implementation of digital resources with reinforced relationships between faculty and students.

Use of dipeptidyl peptidase-4 inhibitors and prognosis of COVID-19 in hospitalized patients with type 2 diabetes: A propensity score analysis from the CORONADO study

AIM

To investigate the association between routine use of dipeptidyl peptidase-4 (DPP-4) inhibitors and the severity of coronavirus disease 2019 (COVID-19) infection in patient with type 2 diabetes in a large multicentric study.

MATERIALS AND METHODS

This study was a secondary analysis of the CORONADO study on 2449 patients with type 2 diabetes (T2D) hospitalized for COVID-19 in 68 French centres. The composite primary endpoint combined tracheal intubation for mechanical ventilation and death within 7 days of admission. Stabilized weights were computed for patients based on propensity score (DPP-4 inhibitors users vs. non-users) and were used in multivariable logistic regression models to estimate the average treatment effect in the treated as inverse probability of treatment weighting (IPTW).

RESULTS

Five hundred and ninety-six participants were under DPP-4 inhibitors before admission to hospital (24.3%). The primary outcome occurred at similar rates in users and non-users of DPP-4 inhibitors (27.7% vs. 28.6%; p = .68). In propensity analysis, the IPTW-adjusted models showed no significant association between the use of DPP-4 inhibitors and the primary outcome by Day 7 (OR [95% CI]: 0.95 [0.77-1.17]) or Day 28 (OR [95% CI]: 0.96 [0.78-1.17]). Similar neutral findings were found between use of DPP-4 inhibitors and the risk of tracheal intubation and death.

CONCLUSIONS

These data support the safety of DPP-4 inhibitors for diabetes management during the COVID-19 pandemic and they should not be discontinued.

Added value of buccal cell FISH analysis in the diagnosis and management of Turner syndrome

STUDY QUESTION

Is there an added diagnosis value of buccal cell FISH analysis compared with blood lymphocyte chromosomal investigations in patients with Turner syndrome (TS)?

SUMMARY ANSWER

Buccal cell FISH analysis, a non-invasive technique, modified the chromosomal results obtained with the blood karyotype in 17 patients (12%) of our cohort.

WHAT IS KNOWN ALREADY

Few studies have evaluated buccal cell FISH analysis and compared them with blood karyotype in patients with TS.

STUDY DESIGN, SIZE, DURATION

A prospective, monocentric cohort study was conducted in a rare diseases centre (CMERC) between July 2017 and August 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 142 adult patients with TS, and at least 5% 45,X cells in a previous blood karyotype, were recruited. All the patients' files were included in the CEMARA database. This national database has been declared to the French data protection agency (CNIL approval number 1187326). In compliance with French law, consent regarding non-opposition to collect and use the data was obtained from each patient. A FISH analysis on a buccal smear was performed.

MAIN RESULTS AND THE ROLE OF CHANCE

The percentage of 45,X cells was identical between the two tissues in only 32.4% of cases. The discrepancy was higher than 41% for 12% of the cohort. The percentage of 45,X cells was higher in blood in 53 (37.3%) patients, and higher in buccal cells in 43 (30.3%) of cases. In 17 (12%) cases, the blood karyotype had to be reconsidered in regard to the buccal cell analysis.

LIMITATIONS, REASONS FOR CAUTION

It would have been interesting to evaluate karyotypes in cells from other tissues such as cells from skin biopsy or from the urinary tract and even from blood vessels or gonads in case of surgery and to compare them with each patient's phenotype. However, most of the time, these tissues are not available.

WIDER IMPLICATIONS OF THE FINDINGS

Although blood lymphocyte karyotype remains the gold standard for the diagnosis of TS, buccal cell FISH analysis is an efficient tool to evaluate the global chromosomal constitution in these patients, thus allowing them to have better care and follow-up. For instance, identifying a Y chromosome can prevent the occurrence of a gonadoblastoma, as gonadectomy should be discussed. On the other hand, finding normal XX cells in a patient with a previous diagnosis of homogenous 45,X TS, may be psychologically helpful and relevant for gynaecological care.

STUDY FUNDING/COMPETING INTEREST(S)

No specific funding was sought for the study. The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Predictors of hospital discharge and mortality in patients with diabetes and COVID-19: updated results from the nationwide CORONADO study

AIMS/HYPOTHESIS

This is an update of the results from the previous report of the CORONADO (Coronavirus SARS-CoV-2 and Diabetes Outcomes) study, which aims to describe the outcomes and prognostic factors in patients with diabetes hospitalised for coronavirus disease-2019 (COVID-19).

METHODS

The CORONADO initiative is a French nationwide multicentre study of patients with diabetes hospitalised for COVID-19 with a 28-day follow-up. The patients were screened after hospital admission from 10 March to 10 April 2020. We mainly focused on hospital discharge and death within 28 days.

RESULTS

We included 2796 participants: 63.7% men, mean age 69.7 ± 13.2 years, median BMI (25th-75th percentile) 28.4 (25.0-32.4) kg/m². Microvascular and macrovascular diabetic complications were found in 44.2% and 38.6% of participants, respectively. Within 28 days, 1404 (50.2%; 95% CI 48.3%, 52.1%) were discharged from hospital with a median duration of hospital stay of 9 (5-14) days, while 577 participants died (20.6%; 95% CI 19.2%, 22.2%). In multivariable models, younger age, routine metformin therapy and longer symptom duration on admission were positively associated with discharge. History of microvascular complications, anticoagulant routine therapy, dyspnoea on admission, and higher aspartate aminotransferase, white cell count and C-reactive protein levels were associated with a reduced chance of discharge. Factors associated with death within 28 days mirrored those associated with discharge, and also included routine treatment by insulin and statin as deleterious factors.

CONCLUSIONS/INTERPRETATION

In patients with diabetes hospitalised for COVID-19, we established prognostic factors for hospital discharge and death that could help clinicians in this pandemic period.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT04324736.

Relationship between obesity and severe COVID-19 outcomes in patients with type 2 diabetes: Results from the CORONADO study

AIM

To assess the relationship between body mass index (BMI) classes and early COVID-19 prognosis in inpatients with type 2 diabetes (T2D).

METHODS

From the CORONAvirus-SARS-CoV-2 and Diabetes Outcomes (CORONADO) study, we conducted an analysis in patients with T2D categorized by four BMI subgroups according to the World Health Organization classification. Clinical characteristics and COVID-19-related outcomes (i.e. intubation for mechanical ventilation [IMV], death and discharge by day 7 [D7]) were analysed according to BMI status.

RESULTS

Among 1965 patients with T2D, 434 (22.1%) normal weight (18.5-24.9 kg/m² , reference group), 726 (36.9%) overweight (25-29.9 kg/m² ) and 805 (41.0%) obese subjects were analysed, including 491 (25.0%) with class I obesity (30-34.9 kg/m² ) and 314 (16.0%) with class II/III obesity (≥35 kg/m² ). In a multivariable-adjusted model, the primary outcome (i.e. IMV and/or death by D7) was significantly associated with overweight (OR 1.65 [1.05-2.59]), class I (OR 1.93 [1.19-3.14]) and class II/III obesity (OR 1.98 [1.11-3.52]). After multivariable adjustment, primary outcome by D7 was significantly associated with obesity in patients aged younger than 75 years, while such an association was no longer found in those aged older than 75 years.

CONCLUSIONS

Overweight and obesity are associated with poor early prognosis in patients with T2D hospitalized for COVID-19. Importantly, the deleterious impact of obesity on COVID-19 prognosis was no longer observed in the elderly, highlighting the need for specific management in this population.

Molecular and Cellular Bases of Lipodystrophy Syndromes

Lipodystrophy syndromes are rare diseases originating from a generalized or partial loss of adipose tissue. Adipose tissue dysfunction results from heterogeneous genetic or acquired causes, but leads to similar metabolic complications with insulin resistance, diabetes, hypertriglyceridemia, nonalcoholic fatty liver disease, dysfunctions of the gonadotropic axis and endocrine defects of adipose tissue with leptin and adiponectin deficiency. Diagnosis, based on clinical and metabolic investigations, and on genetic analyses, is of major importance to adapt medical care and genetic counseling. Molecular and cellular bases of these syndromes involve, among others, altered adipocyte differentiation, structure and/or regulation of the adipocyte lipid droplet, and/or premature cellular senescence. Lipodystrophy syndromes frequently present as systemic diseases with multi-tissue involvement. After an update on the main molecular bases and clinical forms of lipodystrophy, we will focus on topics that have recently emerged in the field. We will discuss the links between lipodystrophy and premature ageing and/or immuno-inflammatory aggressions of adipose tissue, as well as the relationships between lipomatosis and lipodystrophy. Finally, the indications of substitutive therapy with metreleptin, an analog of leptin, which is approved in Europe and USA, will be discussed.

LIPE-related lipodystrophic syndrome: clinical features and disease modeling using adipose stem cells

OBJECTIVE

The term Multiple Symmetric Lipomatosis (MSL) describes a heterogeneous group of rare monogenic disorders and multifactorial conditions, characterized by upper-body adipose masses. Biallelic variants in LIPE encoding hormone-sensitive lipase (HSL), a key lipolytic enzyme, were implicated in three families worldwide. We aimed to further delineate LIPE-related clinical features and pathophysiological determinants.

METHODS

A gene panel was used to identify pathogenic variants. The disease features were reviewed at the French lipodystrophy reference center. The immunohistological, ultrastructural, and protein expression characteristics of lipomatous tissue were determined in surgical samples from one patient. The functional impact of variants was investigated by developing a model of adipose stem cells (ASCs) isolated from lipomatous tissue.

RESULTS

We identified new biallelic LIPE null variants in three unrelated patients referred for MSL and/or partial lipodystrophy. The hallmarks of the disease, appearing in adulthood, included lower-limb lipoatrophy, upper-body and abdominal pseudo-lipomatous masses, diabetes and/or insulin resistance, hypertriglyceridemia, liver steatosis, high blood pressure, and neuromuscular manifestations. Ophthalmological investigations revealed numerous auto-fluorescent drusen-like retinal deposits in all patients. Lipomatous tissue and patient ASCs showed loss of HSL and decreased expression of adipogenic and mature adipocyte markers. LIPE-mutated ASCs displayed impaired adipocyte differentiation, decreased insulin response, defective lipolysis, and mitochondrial dysfunction.

CONSLUSIONS

Biallelic LIPE null variants result in a multisystemic disease requiring multidisciplinary care. Loss of HSL expression impairs adipocyte differentiation, consistent with the lipodystrophy/MSL phenotype and associated metabolic complications. Detailed ophthalmological examination could reveal retinal damage, further pointing to the nervous tissue as an important disease target.

Correction to: Phenotypic characteristics and prognosis of inpatients with COVID-19 and diabetes: the CORONADO study

The authors regret a mistake in Table 1.

Phenotypic characteristics and prognosis of inpatients with COVID-19 and diabetes: the CORONADO study

AIMS/HYPOTHESIS

Coronavirus disease-2019 (COVID-19) is a life-threatening infection caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus. Diabetes has rapidly emerged as a major comorbidity for COVID-19 severity. However, the phenotypic characteristics of diabetes in COVID-19 patients are unknown.

METHODS

We conducted a nationwide multicentre observational study in people with diabetes hospitalised for COVID-19 in 53 French centres in the period 10-31 March 2020. The primary outcome combined tracheal intubation for mechanical ventilation and/or death within 7 days of admission. Age- and sex-adjusted multivariable logistic regressions were performed to assess the prognostic value of clinical and biological features with the endpoint. ORs are reported for a 1 SD increase after standardisation.

RESULTS

The current analysis focused on 1317 participants: 64.9% men, mean age 69.8 ± 13.0 years, median BMI 28.4 (25th-75th percentile: 25.0-32.7) kg/m²; with a predominance of type 2 diabetes (88.5%). Microvascular and macrovascular diabetic complications were found in 46.8% and 40.8% of cases, respectively. The primary outcome was encountered in 29.0% (95% CI 26.6, 31.5) of participants, while 10.6% (9.0, 12.4) died and 18.0% (16.0, 20.2) were discharged on day 7. In univariate analysis, characteristics prior to admission significantly associated with the primary outcome were sex, BMI and previous treatment with renin-angiotensin-aldosterone system (RAAS) blockers, but not age, type of diabetes, HbA_1c, diabetic complications or glucose-lowering therapies. In multivariable analyses with covariates prior to admission, only BMI remained positively associated with the primary outcome (OR 1.28 [1.10, 1.47]). On admission, dyspnoea (OR 2.10 [1.31, 3.35]), as well as lymphocyte count (OR 0.67 [0.50, 0.88]), C-reactive protein (OR 1.93 [1.43, 2.59]) and AST (OR 2.23 [1.70, 2.93]) levels were independent predictors of the primary outcome. Finally, age (OR 2.48 [1.74, 3.53]), treated obstructive sleep apnoea (OR 2.80 [1.46, 5.38]), and microvascular (OR 2.14 [1.16, 3.94]) and macrovascular complications (OR 2.54 [1.44, 4.50]) were independently associated with the risk of death on day 7.

CONCLUSIONS/INTERPRETATIONS

In people with diabetes hospitalised for COVID-19, BMI, but not long-term glucose control, was positively and independently associated with tracheal intubation and/or death within 7 days.

TRIAL REGISTRATION

clinicaltrials.gov NCT04324736.

Peroxisome proliferator-activated receptor gamma-ligand-binding domain mutations associated with familial partial lipodystrophy type 3 disrupt human trophoblast fusion and fibroblast migration

The transcription factor peroxisome proliferator‐activated receptor gamma (PPARG) is essential for placental development, and alterations in its expression and/or activity are associated with human placental pathologies such as pre‐eclampsia or IUGR. However, the molecular regulation of PPARG in cytotrophoblast differentiation and in the underlying mesenchyme remains poorly understood. Our main goal was to study the impact of mutations in the ligand‐binding domain (LBD) of the PPARG gene on cytotrophoblast fusion (PPARG^E352Q) and on fibroblast cell migration (PPARG^R262G/PPARG^L319X). Our results showed that, compared to cells with reconstituted PPARG^WT, transfection with PPARG^E352Q led to significantly lower PPARG activity and lower restoration of trophoblast fusion. Likewise, compared to PPARG^WT fibroblasts, PPARG^R262G/PPARG^L319X fibroblasts demonstrated significantly inhibited cell migration. In conclusion, we report that single missense or nonsense mutations in the LBD of PPARG significantly inhibit cell fusion and migration processes.

European lipodystrophy registry: background and structure

BACKGROUND

Lipodystrophy syndromes comprise a group of extremely rare and heterogeneous diseases characterized by a selective loss of adipose tissue in the absence of nutritional deprivation or catabolic state. Because of the rarity of each lipodystrophy subform, research in this area is difficult and international co-operation mandatory. Therefore, in 2016, the European Consortium of Lipodystrophies (ECLip) decided to create a registry for patients with lipodystrophy.

RESULTS

The registry was build using the information technology Open Source Registry System for Rare Diseases in the EU (OSSE), an open-source software and toolbox. Lipodystrophy specific data forms were developed based on current knowledge of typical signs and symptoms of lipodystrophy. The platform complies with the new General Data Protection Regulation (EU) 2016/679 by ensuring patient pseudonymization, informational separation of powers, secure data storage and security of communication, user authentication, person specific access to data, and recording of access granted to any data. Inclusion criteria are all patients with any form of lipodystrophy (with the exception of HIV-associated lipodystrophy). So far 246 patients from nine centres (Amsterdam, Bologna, Izmir, Leipzig, Münster, Moscow, Pisa, Santiago de Compostela, Ulm) have been recruited. With the help from the six centres on the brink of recruitment (Cambridge, Lille, Nicosia, Paris, Porto, Rome) this number is expected to double within the next one or 2 years.

CONCLUSIONS

A European registry for all patients with lipodystrophy will provide a platform for improved research in the area of lipodystrophy. All physicians from Europe and neighbouring countries caring for patients with lipodystrophy are invited to participate in the ECLip Registry.

STUDY REGISTRATION

ClinicalTrials.gov (NCT03553420). Registered 14 March 2018, retrospectively registered.

Lipodystrophic syndromes: From diagnosis to treatment

Lipodystrophic syndromes are acquired or genetic rare diseases, characterised by a generalised or partial lack of adipose tissue leading to metabolic alterations linked to strong insulin resistance. They encompass a variety of clinical entities due to primary defects in adipose differentiation, in the structure and/or regulation of the adipocyte lipid droplet, or due to immune-inflammatory aggressions, chromatin deregulations and/or mitochondrial dysfunctions affecting adipose tissue. Diagnosis is based on clinical examination, pathological context and comorbidities, and on results of metabolic investigations and genetic analyses, which together determine management and genetic counselling. Early lifestyle and dietary measures focusing on regular physical activity and avoiding excess energy intake are crucial. They are accompanied by multidisciplinary follow-up adapted to each clinical form. In case of hyperglycemia, antidiabetic medications, with metformin as a first-line therapy in adults, are used in addition to lifestyle and dietary modifications. When standard treatments have failed to control metabolic disorders, the orphan drug metreleptin, an analog of leptin, can be effective in certain forms of lipodystrophy syndrome. Metreleptin therapy indications, prescription and monitoring were recently defined in France, representing a major improvement in patient care.

Diagnostic Challenge in PLIN1-Associated Familial Partial Lipodystrophy

CONTEXT

Heterozygous frameshift variants in PLIN1 encoding perilipin-1, a key protein for lipid droplet formation and triglyceride metabolism, have been implicated in familial partial lipodystrophy type 4 (FPLD4), a rare entity with only six families reported worldwide. The pathogenicity of other PLIN1 null variants identified in patients with diabetes and/or hyperinsulinemia was recently questioned because of the absence of lipodystrophy in these individuals and the elevated frequency of PLIN1 null variants in the general population.

OBJECTIVES

To reevaluate the pathogenicity of PLIN1 frameshift variants owing to new data obtained in the largest series of patients with FPLD4.

METHODS

We performed histological and molecular studies for patients referred to our French National Reference Center for Rare Diseases of Insulin Secretion and Insulin Sensitivity for lipodystrophy and/or insulin resistance and carrying PLIN1 frameshift variants.

RESULTS

We identified two heterozygous PLIN1 frameshift variants segregating with the phenotype in nine patients from four unrelated families. The FPLD4 stereotypical signs included postpubertal partial lipoatrophy of variable severity, muscular hypertrophy, acromegaloid features, polycystic ovary syndrome and/or hirsutism, metabolic complications (e.g., hypertriglyceridemia, liver steatosis, insulin resistance, diabetes), and disorganized subcutaneous fat lobules with fibrosis and macrophage infiltration.

CONCLUSIONS

These data suggest that some FPLD4-associated PLIN1 variants are deleterious. Thus, the evidence for the pathogenicity of each variant ought to be carefully considered before genetic counseling, especially given the importance of an early diagnosis for optimal disease management. Thus, we recommend detailed familial investigation, adipose tissue-focused examination, and follow-up of metabolic evolution.

Lipodystrophic syndromes due to LMNA mutations: recent developments on biomolecular aspects, pathophysiological hypotheses and therapeutic perspectives

Mutations in LMNA, encoding A-type lamins, are responsible for laminopathies including muscular dystrophies, lipodystrophies, and premature ageing syndromes. LMNA mutations have been shown to alter nuclear structure and stiffness, binding to partners at the nuclear envelope or within the nucleoplasm, gene expression and/or prelamin A maturation. LMNA-associated lipodystrophic features, combining generalized or partial fat atrophy and metabolic alterations associated with insulin resistance, could result from altered adipocyte differentiation or from altered fat structure.

Recent studies shed some light on how pathogenic A-type lamin variants could trigger lipodystrophy, metabolic complications, and precocious cardiovascular events. Alterations in adipose tissue extracellular matrix and TGF-beta signaling could initiate metabolic inflexibility. Premature senescence of vascular cells could contribute to cardiovascular complications. In affected families, metabolic alterations occur at an earlier age across generations, which could result from epigenetic deregulation induced by LMNA mutations. Novel cellular models recapitulating adipogenic developmental pathways provide scalable tools for disease modeling and therapeutic screening.

Development and Validation of a New Risk Prediction Score for Life-Threatening Ventricular Tachyarrhythmias in Laminopathies

BACKGROUND

An accurate estimation of the risk of life-threatening (LT) ventricular tachyarrhythmia (VTA) in patients with LMNA mutations is crucial to select candidates for implantable cardioverter-defibrillator implantation.

METHODS

We included 839 adult patients with LMNA mutations, including 660 from a French nationwide registry in the development sample, and 179 from other countries, referred to 5 tertiary centers for cardiomyopathies, in the validation sample. LTVTA was defined as (1) sudden cardiac death or (2) implantable cardioverter defibrillator-treated or hemodynamically unstable VTA. The prognostic model was derived using the Fine-Gray regression model. The net reclassification was compared with current clinical practice guidelines. The results are presented as means (SD) or medians [interquartile range].

RESULTS

We included 444 patients, 40.6 (14.1) years of age, in the derivation sample and 145 patients, 38.2 (15.0) years, in the validation sample, of whom 86 (19.3%) and 34 (23.4%) experienced LTVTA over 3.6 [1.0-7.2] and 5.1 [2.0-9.3] years of follow-up, respectively. Predictors of LTVTA in the derivation sample were: male sex, nonmissense LMNA mutation, first degree and higher atrioventricular block, nonsustained ventricular tachycardia, and left ventricular ejection fraction (https://lmna-risk-vta.fr). In the derivation sample, C-index (95% CI) of the model was 0.776 (0.711-0.842), and the calibration slope 0.827. In the external validation sample, the C-index was 0.800 (0.642-0.959), and the calibration slope was 1.082 (95% CI, 0.643-1.522). A 5-year estimated risk threshold ≥7% predicted 96.2% of LTVTA and net reclassified 28.8% of patients with LTVTA in comparison with the guidelines-based approach.

CONCLUSIONS

In comparison with the current standard of care, this risk prediction model for LTVTA in laminopathies significantly facilitated the choice of candidates for implantable cardioverter defibrillators.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT03058185.

SUN-037 Diagnosis Challenge in Type 4 Familial Partial Lipodystrophic Syndrome

Introduction: Type 4 familial partial lipodystrophic syndrome (FPLD4) is an autosomal dominant disease due to frameshift variants of PLIN1 gene. This gene encodes perilipin 1, a protein playing a key role in the structure of the adipocyte lipid droplet and in the regulation of lipolysis. Only 6 independent families with FPLD4 have been described. The aim of this work was to identify the major signs of the disease in the largest cohort of FPLD4 patients reported to date. Patients and Methods: Clinical and biological phenotype of 11 new patients with a family history of lipodystrophic syndrome and bearing a frameshift variant of PLIN1 gene, were investigated after written informed consent. Histological examination, and perilipin 1 protein expression analyses by western blot on whole cell extracts were performed on biopsies of adipose tissue in 2 patients. Results: We identified 3 heterozygous frameshift variants of PLIN1, segregating with the disease in 11 patients from 5 independent families. Our team had already described the p.Val398Glyfs*167 variant, and 2 new variants p.Gly362Glyfs*63 and p.Pro403Argfs*164 were identified. In all patients next generation sequencing (NGS) excluded any other molecular defect known to be responsible for lipodystrophy. On the studied adipose tissue samples, the PLIN1 variant leads to an abnormal longer form of perilipin 1 with fat fibrosis. The main signs of FPLD4 associate a partial, but also sometimes generalized lipoatrophy of post-pubertal occurrence and a phenotype of variable severity including muscular hypertrophy, acromegaloid facies, hirsutism, and metabolic complications (hypertriglyceridemia, insulin-resistance, diabetes, liver steatosis). Lipoatrophy might be missing or difficult to identify in men and youth. Leptin level was low or inappropriate to BMI, which was below 30 but not always very low. Conclusion: The clinical phenotype of FPLD4 is quite homogeneous, but the clinical diagnosis requires a careful clinical examination and/or an expert advice. An early genetic diagnosis is recommended to confirm the disease and prevent metabolic complications.

Monogenic forms of lipodystrophic syndromes: diagnosis, detection, and practical management considerations from clinical cases

BACKGROUND

Lipodystrophic syndromes are rare diseases of genetic or acquired origin characterized by partial or generalized lack of body fat. Early detection and diagnosis are crucial to prevent and manage associated metabolic dysfunctions, i.e. insulin resistance, dyslipidemia, fatty liver, and diabetes, and to provide appropriate genetic counseling. By means of several representative case studies, this article illustrates the diagnostic and management challenges of lipodystrophic syndromes.

REVIEW

Berardinelli-Seip congenital lipodystrophy (BSCL) is typically diagnosed at birth, or soon thereafter, with generalized lipoatrophy and hepatomegaly secondary to hepatic steatosis. Physicians must also consider this diagnosis in adults with atypical non-autoimmune diabetes, hypertriglyceridemia, and a lean and muscular phenotype. The BSCL1 subtype due to mutations in the AGPAT2 gene can have an unusual presentation, especially in neonates and infants. Particular attention should be paid to infants presenting failure to thrive who also have hepatomegaly and metabolic derangements. The BSCL2 sub-type due to mutations in the BSCL gene tends to be more severe than BSCL1, and is characterized by greater fat loss, mild intellectual disability, earlier onset of diabetes, and higher incidence of premature death. Effective management from an earlier age may moderate the natural disease course. Partial lipodystrophies may easily be confused with common central obesity and/or metabolic syndrome. In patients with unexplained pancreatitis and hypertriglyceridemia, lipodystrophies such as familial partial lipodystrophy type 2 (FPLD2; Dunnigan type, due to LMNA mutations) should be considered. Oral combined contraceptives, which can reveal the disease by inducing severe hypertriglyceridemia, are contraindicated. Endogenous estrogens may also lead to "unmasking" of the FPLD2 phenotype, which often appears at puberty, and is more severe in females than males.

CONCLUSIONS

Diet and exercise, adapted to age and potential comorbidities, are essential prerequisites for therapeutic management of lipodystrophic syndromes. Metreleptin therapy can be useful to manage lipodystrophy-related metabolic complications.

Severe Congenital Adrenal Hyperplasia Presenting as Bilateral Testicular Tumors and Azoospermia in the Third Decade of Life

Classic forms of 21-hydroxylase deficiency (21OHD) are usually diagnosed at birth by salt wasting or precocious puberty in male patients. Here we report the case of a 32-year-old male patient who presented with azoospermia and bilateral testicular tumors. He was referred to our endocrine unit after testicular surgery. His gonadotropins were undetectable. Liquid chromatography-tandem mass spectrometry revealed a high serum progesterone level, high 17-hydroxyprogesterone (17OHP) (255 ng/mL), and high levels of 17OHP metabolites, suggesting a classic form of 21OHD. His blood pressure was normal. Molecular analysis showed a homozygous large 21-hydroxylase gene (CYP21A2) conversion. Furthermore, an adrenal CT scan revealed voluminous, heterogeneous bilateral and asymmetric adrenal masses containing calcifications. Our case report illustrates the fact that a classic form of 21OHD can be diagnosed in late adulthood, manifested by azoospermia and large adrenal tumors, associated with elevated 17OHP.

MFN2-associated lipomatosis: Clinical spectrum and impact on adipose tissue

BACKGROUND

Multiple symmetric lipomatosis (MSL) is characterized by upper-body lipomatous masses frequently associated with metabolic and neurological signs. MFN2 pathogenic variants were recently implicated in a very rare autosomal recessive form of MSL. MFN2 encodes mitofusin-2, a mitochondrial fusion protein previously involved in Charcot-Marie-Tooth neuropathy.

OBJECTIVE

To investigate the clinical, metabolic, tissular, and molecular characteristics of MFN2-associated MSL.

METHODS

We sequenced MFN2 in 66 patients referred for altered fat distribution with one or several lipomas or lipoma-like regions and performed clinical and metabolic investigations in patients with positive genetic testing. Lipomatous tissues were studied in 3 patients.

RESULTS

Six patients from 5 families carried a homozygous p.Arg707Trp pathogenic variant, representing the largest reported series of MFN2-associated MSL. Patients presented both lipomatous masses and a lipodystrophic syndrome (lipoatrophy, low leptinemia and adiponectinemia, hypertriglyceridemia, insulin resistance and/or diabetes). Charcot-Marie-Tooth neuropathy was of highly variable clinical severity. Lipomatous tissue mainly contained hyperplastic unilocular adipocytes, with few multilocular cells. It displayed numerous mitochondrial alterations (increased number and size, structural defects). As compared to control subcutaneous fat, mRNA and protein expression of leptin and adiponectin was strikingly decreased, whereas the CITED1 and fibroblast growth factor 21 (FGF21) thermogenic markers were strongly overexpressed. Consistently, serum FGF21 was markedly increased, and ¹⁸F-FDG-PET-scan revealed increased fat metabolic activity.

CONCLUSION

MFN2-related MSL is a novel mitochondrial lipodystrophic syndrome involving both lipomatous masses and lipoatrophy. Its complex neurological and metabolic phenotype justifies careful clinical evaluation and multidisciplinary care. Low leptinemia and adiponectinemia, high serum FGF21, and increased ¹⁸F-FDG body fat uptake may be disease markers.

LMNA-associated partial lipodystrophy: anticipation of metabolic complications

Background

Type-2 familial partial lipodystrophy (FPLD2) is a rare autosomal dominant lipodystrophic disorder due to mutations inLMNAencoding lamin A/C, a key epigenetic regulator. FPLD2 severity is determined by the occurrence of metabolic complications, especially diabetes and hypertriglyceridaemia. We evaluated the disease history and severity over generations.

Methods

This retrospective study of the largest cohort of patients with FPLD2 reported to date investigates 85 patients from 24 families comprising three generations (G1: n=39; G2: n=41; G3: n=5).

Results

Lipodystrophy appears with the same characteristics and at the same age in first generation (G1;18.6±1.5 years) and second generation (G2;15.9±0.8 years). Despite similar body mass index (23.7±0.6 vs 23.8±0.6 kg/m2), the mean delay between the onset of lipodystrophy and diabetes was far shorter in G2 (10.5±2.4 years) than in G1 (29.0±3.5 years) (p=0.0002). The same is true for the delay preceding hypertriglyceridaemia (G2: 4.5±1.4; G1: 19.3±3.2 years) (p=0.002), revealing an anticipation phenomenon. Observations in G3, and analysis within each family of disease history and diagnostic procedures, confirmed this result.

Conclusions

This study is a rare example of anticipation unrelated to a trinucleotide expansion. Discovery of this early occurrence of metabolic complications in young generations underlines the utility of presymptomatic genetic diagnosis, with careful metabolic screening and preventive lifestyle in all at-risk individuals.

Bone imaging findings in genetic and acquired lipodystrophic syndromes: an imaging study of 24 cases

OBJECTIVE

To describe the bone imaging features of lipodystrophies in the largest cohort ever published.

MATERIALS AND METHODS

We retrospectively examined bone imaging data in 24 patients with lipodystrophic syndromes. Twenty-two had genetic lipodystrophy: 12/22 familial partial lipodystrophy (FPLD) and 10/22 congenital generalized lipodystrophy (CGL), 8 with AGPAT2-linked CGL1 and 2 with seipin-linked CGL2. Two patients had acquired generalized lipodystrophy (AGL) in a context of non-specific autoimmune disorders. Skeletal radiographs were available for all patients, with radiographic follow-up for two. Four patients with CGL1 underwent MRI, and two of them also underwent CT.

RESULTS

Patients with FPLD showed non-specific degenerative radiographic abnormalities. Conversely, CGL patients showed three types of specific radiographic alterations: diffuse osteosclerosis (in 7 patients, 6 with CGL1 and 1 with CGL2), well-defined osteolytic lesions sparing the axial skeleton (7 CGL1 and 1 CGL2), and pseudo-osteopoikilosis (4 CGL1). Pseudo-osteopoikilosis was the sole bone abnormality observed in one of the two patients with AGL. Osteolytic lesions showed homogeneous low signal intensity (SI) on T1-weighted and high SI on T2-weighted MR images. Most of them were asymptomatic, although one osteolytic lesion resulted in a spontaneous knee fracture and secondary osteoarthritis in a patient with CGL1. MRI also showed diffuse fatty bone marrow alterations in patients with CGL1, with intermediate T1 and high T2 SI, notably in radiographically normal areas.

CONCLUSIONS

The three types of peculiar imaging bone abnormalities observed in generalized lipodystrophic syndromes (diffuse osteosclerosis, lytic lesions and/or pseudo-osteopoikilosis) may help clinicians with an early diagnosis in pauci-symptomatic patients.

One-year metreleptin improves insulin secretion in patients with diabetes linked to genetic lipodystrophic syndromes

Recombinant methionyl human leptin (metreleptin) therapy was shown to improve hyperglycaemia, dyslipidaemia and insulin sensitivity in patients with lipodystrophic syndromes, but its effects on insulin secretion remain controversial. We used dynamic intravenous (i.v.) clamp procedures to measure insulin secretion, adjusted to insulin sensitivity, at baseline and after 1 year of metreleptin therapy, in 16 consecutive patients with lipodystrophy, diabetes and leptin deficiency. Patients, with a mean [± standard error of the mean (s.e.m.)] age of 39.2 (±4) years, presented with familial partial lipodystrophy (n = 11, 10 women) or congenital generalized lipodystrophy (n = 5, four women). Their mean (± s.e.m.) BMI (23.9 ± 0.7 kg/m(2) ), glycated haemoglobin levels (8.5 ± 0.4%) and serum triglycerides levels (4.6 ± 0.9 mmol/l) significantly decreased within 1 month of metreleptin therapy, then remained stable. Insulin sensitivity (from hyperglycaemic or euglycaemic-hyperinsulinaemic clamps, n = 4 and n = 12, respectively), insulin secretion during graded glucose infusion (n = 12), and acute insulin response to i.v. glucose adjusted to insulin sensitivity (disposition index, n = 12), significantly increased after 1 year of metreleptin therapy. The increase in disposition index was related to a decrease in percentage of total and trunk body fat. Metreleptin therapy improves not only insulin sensitivity, but also insulin secretion in patients with diabetes attributable to genetic lipodystrophies.