Generalized Lipodystrophy Research Articles

Endogenous Leptin Concentrations Poorly Predict Metreleptin Response in Patients With Partial Lipodystrophy.

Leptin replacement with metreleptin improves glycemia and hypertriglyceridemia in severely hypoleptinemic patients with generalized lipodystrophy (GLD), but its effects are variable in partially leptin-deficient patients with partial lipodystrophy (PLD). Compare 3 leptin assays (Study I); identify diagnostic performance of leptin assays to detect responders to metreleptin for each assay (Study II). Study I: cross-sectional analysis of average bias between leptin assays. Study II: retrospective analysis of diagnostic accuracy of potential leptin cut points to detect clinical responders to metreleptin. National Institutes of Health; University of Michigan. Study I: Metreleptin-naïve patients with lipodystrophy (GLD, n = 33, PLD, n = 67) and healthy volunteers (n = 239). Study II: GLD (n = 66) and PLD (n = 84) patients treated with metreleptin for 12 months. Leptin concentrations by Millipore radioimmunoassay (RIA), Millipore enzyme-linked immunosorbent assay (MELISA), and R&D Systems enzyme-linked immunosorbent assay (RDELISA). Response to metreleptin therapy was defined as either reduction ≥1.0% in A1c or ≥30% in serum triglycerides. RDELISA measured 3.0 ± 9.5 ng/mL higher than RIA; MELISA measured 11.0 ± 17.8 and 14.0 ±19.2 less than RIA and RDELISA, respectively. Leptin by RIA, MELISA, and RDELISA modestly predicted metreleptin response in GLD + PLD [receiver operating characteristic (ROC) area under the curve (AUC) 0.74, 0.69, and 0.71, respectively; P < 0.01 for all] with lower predictive power in PLD (ROC AUC 0.63, 0.61 and 0.65, respectively; P > 0.05 for all). The only reproducible cut point identified on sensitivity analyses was RIA leptin 7.2 ng/mL (sensitivity 56%; specificity 78%). Three common leptin assays are not interchangeable, and a reliable cut point to select responders to metreleptin was not identified.

RNA-seq of peripheral blood mononuclear cells of congenital generalized lipodystrophy type 2 patients

Illumina RNA-seq analysis was used to characterize the whole transcriptomes of peripheral blood mononuclear cells (PBMCs) from patients with congenital generalized lipodystrophy. RNA-seq information for seven patients with type 2 congenital generalized lipodystrophy (CGL2; Berardinelli-Seip congenital lipodystrophy, BSCL2) was obtained and compared with similar information for seven age- and sex-matched healthy control subjects. All seven CGL2 patients carried biallelic pathogenic mutations affecting the BSCL2 gene and had clinical symptoms of varying severity. The findings provide the whole-transcriptome signatures of PBMCs of CGL2 patients, allowing further exploration of gene expression patterns/signatures associated with the various clinical symptoms of patients with this disease.

Reduced Endothelial Leptin Signaling Increases Vascular Adrenergic Reactivity in a Mouse Model of Congenital Generalized Lipodystrophy.

The adipokine leptin, which is best-known for its role in the control of metabolic function, is also a master regulator of cardiovascular function. While leptin has been approved for the treatment of metabolic disorders in patients with congenital generalized lipodystrophy (CGL), the effects of chronic leptin deficiency and the treatment on vascular contractility remain unknown. Herein, we investigated the effects of leptin deficiency and treatment (0.3 mg/day/7 days) on aortic contractility in male Berardinelli-Seip 2 gene deficient mice (gBscl2-/-, model of CGL) and their wild-type control (gBscl2+/+), as well as in mice with selective deficiency in endothelial leptin receptor (LepREC-/-). Lipodystrophy selectively increased vascular adrenergic contractility via NO-independent mechanisms and induced hypertrophic vascular remodeling. Leptin treatment and Nox1 inhibition blunted adrenergic hypercontractility in gBscl2-/- mice, however, leptin failed to rescue vascular media thickness. Selective deficiency in endothelial leptin receptor did not alter baseline adrenergic contractility but abolished leptin-mediated reduction in adrenergic contractility, supporting the contribution of endothelium-dependent mechanisms. These data reveal a new direct role for endothelial leptin receptors in the control of vascular contractility and homeostasis, and present leptin as a safe therapy for the treatment of vascular disease in CGL.

Effects of metreleptin in patients with lipodystrophy with and without baseline concomitant medication use

Objective To evaluate the effects of metreleptin in distinct subgroups of patients with generalized lipodystrophy (GL) and partial lipodystrophy (PL), using multivariate linear regression modeling to account for the role of patients’ baseline usage of concomitant glucose and lipid-lowering medications and other covariates on their outcomes. Materials and methods A post-hoc statistical analysis of two published single-arm, interventional, phase 2 clinical trials at NIH was conducted. Concomitant medication use was assessed for the clinical trial population using prescription fill data, measured at baseline and the post-one year following metreleptin initiation. Pre-specified co-primary efficacy endpoints measured were change from baseline in HbA1c at month 12, and the percent change from baseline in fasting serum triglycerides (TG) at month 12. Descriptive and statistical analyses were conducted for the overall population, the separate populations with GL and PL, and additional PL subgroups defined by baseline metabolic markers of elevated HbA1c and elevated fasting TG. Results As previously reported, improvement in HbA1c and fasting TG from baseline to 12 months on metreleptin were observed in the overall population (mean change −1.57 percentage points and median change −37.9%, respectively) and subgroups. For both HbA1c and TG, baseline levels were significant predictors of changes after metreleptin. After considering baseline characteristics such as disease type, age, sex, and baseline HbA1c, baseline insulin use was not found to be a significant predictor of HbA1c improvement following metreleptin initiation. Similar results were seen for TG levels, with the use of any lipid-lowering medications at baseline not found to be a significant predictor of reductions in fasting TG levels. Conclusions Patients treated with metreleptin experienced statistically significant improvement in metabolic markers of glycemic and hypertriglyceridemic control—e.g. HbA1c and triglyceride levels—across various subgroups after controlling for baseline characteristics and concomitant medication usage.

Generalized lipoatrophy syndromes

Generalized lipodystrophy (GL) syndromes are a group of rare heterogenous disorders, characterized by total subcutaneous fat loss. The frequency of GL is currently assessed as approximately 0,23 cases per million of the population, in Europe – as 0,96 cases per million of the population. They can be congenital (CGL) or acquired (AGL) depending on the etiology and the time of the onset of fat loss. Both CGL and AGL are often associated with different metabolic complications, such as hypertriglyceridemia, insulin resistance and lipoatrophic diabetes mellitus, metabolically associated FLD, arterial hypertension, proteinuria, reproductive system disorders. In this review we aimed to summarize the information on all forms of generalized lipodystrophy, especially the ones of genetic etiology, their clinical manifestations and complications, the perspectives for diagnostics, treatment and further research.

Bone Mineral Density in Congenital Generalized Lipodystrophy: The Role of Bone Marrow Tissue, Adipokines, and Insulin Resistance.

Congenital Generalized Lipodystrophy (CGL) is a rare syndrome characterized by the almost total absence of subcutaneous adipose tissue due to the inability of storing lipid in adipocytes. Patients present generalized lack of subcutaneous fat and normal to low weight. They evolve with severe metabolic disorders, non-alcoholic fatty liver disease, early cardiac abnormalities, and infectious complications. Although low body weight is a known risk factor for osteoporosis, it has been reported that type 1 and 2 CGL have a tendency of high bone mineral density (BMD). In this review, we discuss the role of bone marrow tissue, adipokines, and insulin resistance in the setting of the normal to high BMD of CGL patients. Data bases from Pubmed and LILACS were searched, and 113 articles published until 10 April 2021 were obtained. Of these, 76 were excluded for not covering the review topic. A manual search for additional literature was performed using the bibliographies of the studies located. The elucidation of the mechanisms responsible for the increase in BMD in this unique model of insulin resistance may contribute to the understanding of the interrelationships between bone, muscle, and adipose tissue in a pathophysiological and therapeutic perspective.

Abstract P462: Bscl2/seipin Deficiency In Heart Causes Energy Deficit And Heart Failure Via Inducing Excessive Lipid Catabolism

Heart failure (HF) is one of the leading causes of death world-wide and is associated with cardiac metabolic perturbations. Human Type 2 Berardinelli-Seip Congenital Lipodystrophy (BSCL2) disease is caused by mutations in the BSCL2 gene. Global lipodystrophic Bscl2 –/– mice exhibit hypertrophic cardiomyopathy. Whether BSCL2 plays a direct role in regulating cardiac substrate metabolism and/or contractile function remains unknown. Here we show that mice with cardiac-specific deletion of Bscl2 ( Bscl2 cKO ) developed dilated HF. Myocardial BSCL2 deletion led to elevated ATGL expression and FA oxidation (FAO) along with reduced cardiac lipid contents. Cardiac dysfunction in Bscl2 cKO mice was independent of mitochondrial dysfunction and oxidative stress, but associated with decreased metabolic reserve and ATP levels. Importantly, heart failure in Bscl2 cKO mice could be partially reversed by pharmacological inhibition of FAO, or prevented by high fat diet (HFD) feeding. Lipidomic analysis further identified markedly reduced glycerolipids, glycerophospholipids, NEFA and acylcarnitines in Bscl2 cKO hearts, which were partially normalized by FAO inhibition or HFD. Our study reveals a new form of HF with excessive lipid catabolism, and identifies a crucial cardiomyocyte-specific role of BSCL2 in controlling cardiac lipid catabolism, energy state and contractile function. It also provides novel insights into metabolically treating energy-starved HF using FAO inhibitor or HFD.

SARS-COV-2 infection outcomes in patients with congenital generalized lipodystrophy

BackgroundA new strain of human coronavirus (HCoV) spread rapidly around the world. Diabetes and obesity are associated with a worse prognosis in these patients. Congenital Generalized Lipodystrophy (CGL) patients generally have poorly controlled diabetes and require extremely high doses of insulin. There is no documentation in the literature of cases of COVID in CGL patients. Thus, we aimed to evaluate the prevalence of SARS-CoV-2 infection in CGL patients, and the association of their clinical and metabolic characteristics and outcomes.MethodsThis is a cross-sectional study carried out between July and October 2020. Clinical data collected were respiratory or other flu-like symptoms, need of hospitalization in the last three months, CGL comorbidities, and medications in use. Cholesterol, triglycerides, glycohemoglobin A1c levels, anti-SARS-CoV-2 antibodies and nasopharyngeal swab for RT-qPCR were also obtained in all CGL patients. Mann-Whitney U test was used to analyze the characteristics of the participants, verifying the non-adherence of the data to the Gaussian distribution. In investigating the association between categorical variables, we used Pearson's chi-square test and Fisher's exact test. A significance level of 5% was adopted.ResultsTwenty-two CGL patients were assessed. Eight subjects (36.4%) had reactive anti-SARS-CoV-2 antibodies. Only one of these, also presented detectable RT-qPCR. Five individuals (62.5%) were women, median age of 13.5 years (1 to 37). Symptoms like fever, malaise, nausea, diarrhea and chest pain were present, and all asymptomatic patients were children. All subjects had inadequate metabolic control, with no difference between groups. Among positive individuals there was no difference between those with AGPAT2 (75%) and BSCL2 gene mutations (25%) (p > 0.05). No patient needed hospitalization or died.ConclusionsWe described a high prevalence of SARS-CoV-2 infection in CGL patients with a good outcome in all of them. These findings suggest that at least young CGL patients infected by SARS-COV-2 are not at higher risk of poor outcome, despite known severe metabolic comorbidities.

PRO10 Indirect Treatment Comparison of Myalepta (Metreleptin) Compared to Best Supportive Care in Lipodystrophy

Metreleptin is the first approved medicine for the treatment of the complications of lipodystrophy. In the absence of head-to-head studies comparing metreleptin with best supportive care (BSC), the objective of this analysis was to estimate the treatment effect of metreleptin compared to BSC on the metabolic complications of lipodystrophy in generalised lipodystrophy (GL) or partial lipodystrophy (PL) patients. Patient-level data from two single arm studies were utilised to carry out an indirect treatment comparison: the GL/PL Natural History study, an observational study of patients receiving BSC, and the National Institute of Health (NIH) follow-up study, an extended follow-up to patients enrolled in the metreleptin NIH studies 991265/200110769. Analysis methodology was aligned to NICE Decision Support Unit guidelines. Two relevant adjustment methods were identified: multivariate regression and inverse probability weighting (IPW). Three covariates were included in the adjustment models – age, gender, and lipodystrophy type (generalised or partial). Outcomes evaluated included change in haemoglobin A1c (HbA1c), triglycerides, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) from baseline to 1 year, as well as the incidence of pancreatitis. The results supported statistical rationale for using the IPW methodology as the primary analysis. A statistically significant adjusted treatment effect (ATE) was estimated for change in HbA1c (-1.52%; p<0.001), triglycerides (-915 mg/dl, p<0.001), ALT (-44 U/L, p<0.001), AST (-28 U/L, p<0.001) and episodes of pancreatitis (odds ratio (OR): 0.94, p=0.01) for metreleptin versus BSC. Results were consistent across multivariate regression analyses. Metreleptin produced significant and clinical meaningful reductions in HbA1c, triglycerides, ALT, AST, and episodes of pancreatitis compared to BSC, and can be considered standard of care therapy to treat the metabolic complications in patients with lipodystrophy.

Metreleptin and Metformin Use in an Infant With Congenital Generalized Lipodystrophy Secondary to AGPAT2 Mutation

Background: Congenital generalized lipodystrophy (CGL) is a rare inherited disease characterized by widespread loss of subcutaneous fat and severe metabolic abnormalities. Metreleptin, a synthetic analog of leptin, is a treatment modality that has been shown to decrease fasting triglycerides, fasting glucose, and HbA1c. Metformin use in infants has only been described in a few case reports of CGL and Donohue syndrome (insulin receptor mutation), and there is no established dosing for this age group. We report metreleptin, insulin, and metformin use in an infant with type 1 CGL who presented with marked hypertriglyceridemia, hypoleptinemia, hyperglycemia, and transaminitis.Clinical Case: A 2-month-old African American female born SGA at term presented to her primary care physician for a well child check where she was noted to have poor weight gain, hyperphagia, and abdominal distension. She was subsequently admitted for failure to thrive with weight z-score of -2.17 and length z-score of -0.15. Initial labs were notable for triglycerides of 5,167 mg/dL, HDL 10 mg/dL, blood glucose 324 mg/dL, ALT 212 units/L, AST 215 units/L, and bicarbonate of 17 mmol/L. A random insulin level was elevated at 257 mcIU/mL. Adiponectin was undetectable and leptin was low at 0.3 ng/mL. Hemoglobin A1c was in diabetes mellitus range at 8.9%. She was started on detemir 1.0 units/kg/day on day 1 (titrated to a maximum dose of 4.4 units/kg/day) and metformin 50 mg/kg/day on day 3 of hospitalization. By day 4, triglycerides decreased to 758 mg/dL, AST to 119 units/L and ALT to 124 units/L. Pre-prandial glucoses improved ranging from 113 to 138 mg/dL. As her insurance denied coverage for detemir, she was discharged home on glargine 0.7 units/kg/day and metformin suspension. One month later, she was started on subcutaneous metreleptin, and glargine was discontinued. At 5 months of age, she had triglycerides 229 mg/dl, normal liver enzymes, and normal blood glucoses while on 0.056 mg/kg/day of subcutaneous metreleptin and metformin. Medications were well tolerated without side effects. She had improved growth and met all developmental milestones. Genetic evaluation revealed that she was homozygous for a pathogenic variant, c.589-2A>G; p.Gln196fs*228 (rs116807569), in the AGPAT2 gene.Conclusion: Leptin is important in regulation of lipid and glucose metabolism, and patients with CGL are deficient due to lack of adipose tissue. Metabolic abnormalities, including stabilization of glucoses and improved hypertriglyceridemia, in our patient markedly improved with initiation of metreleptin, metformin, and insulin. We present successful dosing of these treatment modalities without adverse reactions in an infant with CGL.

Long Term Effects of Leptin on Hepatic Fibrosis in Generalized Lipodystrophy

Lipodystrophy syndromes are caused by deficiency of adipose tissue leading to severe insulin resistance, hypertriglyceridemia, and non-alcoholic fatty liver disease (NAFLD), which may progress to cirrhosis. Advanced fibrosis/cirrhosis was previously thought to be irreversible; however, eradication of hepatitis C or long-term viral suppression of hepatitis B can reverse cirrhosis. Metreleptin treatment in patients with lipodystrophy improves liver transaminases and NAFLD activity score (NAS) after a mean of 2 years, but the latter improvements were due to lower inflammation and steatosis, with no change in fibrosis. The long-term effects of metreleptin in subjects with advanced fibrosis are unknown. We analyzed 24 subjects with advanced fibrosis (NAS stage 3 or 4) prior to metreleptin. Seven had liver biopsies both before and after ≥ 3 years of metreleptin with mean treatment duration 7.8±2.9 years. Five of six subjects with stage 3 fibrosis at baseline had improved fibrosis scores after metreleptin, and 0 of 1 with stage 4 fibrosis improved. 17 patients (8 with stage 3, 9 stage 4) did not have follow up biopsies after ≥3 years. Of these 17, 4 (all stage 4) died from end stage liver disease, and 1 (stage 3) from other causes. There was no clinical indication for repeat biopsy in 6 patients (2 stage 3, 4 stage 4). 6 were lost to follow up. Of the 24 patients with advanced fibrosis, 13 had congenital generalized lipodystrophy (CGL), 7 had acquired generalized lipodystrophy (AGL), 3 had familial partial lipodystrophy (FPL) and 1 had acquired partial lipodystrophy (APL). Of the 5 subjects with improvement in their fibrosis score, 2 had AGL, 2 had CGL, and one had a novel FPL mutation (1). Of the two patients that did not improve, one had FPL and one had CGL. In conclusion, subjects with stage 3 fibrosis due to lipodystrophy may have regression of fibrosis after long-term metreleptin treatment. This improvement may be secondary to near-elimination of the inciting factors (excess nutrient intake leading to ectopic lipid storage in the liver), analogous to clearance of Hepatitis C infection. However, additional data is needed to determine if metreleptin can reverse fibrosis in subjects with stage 4 fibrosis.

BSCL2/Seipin in Lipid metabolism and Lipodystrophy

Adipose tissue is the body's largest endocrine organ that plays a major role in systemic energy homeostasis and thermoregulation. Mutations in BSCL2 (a.k.a. Seipin) gene underlie human type 2 Berardinelli-Seip Congenital Lipodystrophy (BSCL2) disease with near absence of adipose tissue at birth and severe metabolic diseases. Global Bscl2−/− mice largely recapitulate human BSCL2 lipodystrophy. Seipin is known for its critical role in controlling lipid droplet (LD) assembly at the LD-forming subdomain of the endoplasmic reticulum (ER), but its exact functional role has been enigmatic. Our laboratory has focused on elucidating the mechanisms through which Seipin regulates adipocyte differentiation, lipodystrophy and its associated metabolic diseases. This presentation will focus on the physiological role of Seipin in mediating cAMP/PKA signaling to regulate lipid catabolism in mature white adipose tissue (WAT) and brown adipose tissue (BAT) which exerts profound impact on metabolic homeostasis and thermogenesis. We will also explore the role of Seipin as a key node that links ATGL-mediated lipolysis to mitochondrial function in WAT, BAT and heart. These findings will provide novel insights into Seipin's role in cellular and organismal biology and its importance in human health.

Effect of Leptin Therapy on Survival in Generalized and Partial Lipodystrophy: A Matched Cohort Analysis.

ContextData quantifying the impact of metreleptin therapy on survival in non-human immunodeficiency virus (HIV)-related generalized lipodystrophy (GL) and partial lipodystrophy (PL) are unavailable.ObjectiveThis study aimed to estimate the treatment effect of metreleptin on survival in patients with GL and PL.Design/Setting/PatientsDemographic and clinical characteristics were used to match metreleptin-treated and metreleptin-naïve patients with GL and PL. Differences in mortality risk were estimated between matched cohorts of metreleptin-treated and metreleptin-naïve patient cohorts using Cox proportional hazard models. Sensitivity analyses assessed the impact of study assumptions and the robustness of results.Outcome MeasuresThis study assessed time-to-mortality and risk of mortality.ResultsThe analysis evaluated 103 metreleptin-naïve patients with characteristics matched to 103 metreleptin-treated patients at treatment initiation. Even after matching, some metabolic and organ abnormalities were more prevalent in the metreleptin-treated cohort due to bias toward treating more severely affected patients. A Cox proportional hazards model associated metreleptin therapy with an estimated 65% decrease in mortality risk (hazard ratio [HR] 0.348, 95% confidence interval (CI): 0.134–0.900; P = 0.029) even though the actual number of events were relatively small. Results were robust across a broad range of alternate methodological assumptions. Kaplan–Meier estimates of time-to-mortality for the metreleptin-treated and the matched metreleptin-naïve cohorts were comparable.ConclusionsMetreleptin therapy was associated with a reduction in mortality risk in patients with lipodystrophy syndromes despite greater disease severity in treated patients, supporting the view that metreleptin can have a positive disease-modifying impact. Confirmatory studies in additional real-world and clinical datasets are warranted.

Atypical progeroid syndrome (p.E262K LMNA mutation): a rare cause of short stature and osteoporosis.

SummaryLamin A/C (LMNA) gene mutations cause a heterogeneous group of progeroid disorders, including Hutchinson–Gilford progeria syndrome, mandibuloacral dysplasia, atypical progeroid syndrome (APS) and generalized lipodystrophy-associated progeroid syndrome (GLPS). All of those syndromes are associated with some progeroid features, lipodystrophy and metabolic complications but vary differently depending on a particular mutation and even patients carrying the same gene variant are known to have clinical heterogeneity. We report a new 30-year-old female patient from Russia with an APS and generalized lipodystrophy (GL) due to the heterozygous de novo LMNA p.E262K mutation and compare her clinical and metabolic features to those of other described patients with APS. Despite many health issues, short stature, skeletal problems, GL and late diagnosis of APS, our patient seems to be relatively metabolically healthy for her age when compared to previously described patients with APS.Learning pointsAtypical progeroid syndromes (APS) are rare and heterogenic with different age of onset and degree of metabolic disorders, which makes this diagnosis very challenging for clinicians and may be missed until the adulthood.The clinical picture of the APS depends on a particular mutation in the LMNA gene, but may vary even between the patients with the same mutation.The APS due to a heterozygous LMNA p.E262K mutation, which we report in this patient, seems to have association with the generalized lipodystrophy, short stature and osteoporosis, but otherwise, it seems to cause relatively mild metabolic complications by the age of 30.The patients with APS and lipodystrophy syndromes require a personalized and multidisciplinary approach, and so they should be referred to highly specialized reference-centres for diagnostics and treatment as early as possible.Because of the high heterogeneity of such a rare disease as APS, every patient’s description is noteworthy for a better understanding of this challenging syndrome, including the analysis of genotype-phenotype correlations.

Effects of Metreleptin on Patient Outcomes and Quality of Life in Generalized and Partial Lipodystrophy.

Generalized and partial lipodystrophy are rare and complex diseases with progressive clinical and humanistic burdens stemming from selective absence of subcutaneous adipose tissue, which causes reduced energy storage capacity and a deficiency of adipokines such as leptin. Treatment options were limited before leptin replacement therapy (metreleptin) became available. This retrospective study evaluates both clinical and humanistic consequences of the disease and treatment. Chart data were abstracted from a cohort of metreleptin-treated patients with generalized and partial lipodystrophy (n = 112) treated at the US National Institutes of Health. To quantify the quality-of-life consequences of the lipodystrophy disease attributes recorded in chart data, a discrete choice experiment was completed in 6 countries (US, n = 250; EU, n = 750). Resulting utility decrements were used to estimate the quality-adjusted life-year consequences of changes in lipodystrophy attribute prevalence before and after metreleptin. In addition to metabolic impairment, patients with generalized and partial lipodystrophy experienced a range of lipodystrophy consequences, including liver abnormality (94%), hyperphagia (79%), impaired physical appearance (77%), kidney abnormality (63%), reproductive dysfunction (80% of females of reproductive age), and pancreatitis (39%). Improvement was observed in these attributes following initiation of metreleptin. Quality-adjusted life-year gains associated with 12 months of treatment with metreleptin were estimated at 0.313 for generalized and 0.117 for partial lipodystrophy, reducing the gap in quality of life between untreated lipodystrophy and perfect health by approximately 59% and 31%, respectively. This study demonstrates that metreleptin is associated with meaningful clinical and quality-of-life improvements.

Structural Changes in Kir3.2 Channels Leading to Loss of K+ Selectivity

Inwardly rectifying potassium (Kir) channels are essential for numerous physiological processes, including neuronal and cardiac excitability. Recently, the very rare disease Keppen-Lubinsky syndrome (KPLBS), caused by de novo heterozygous mutations in the Kir3.2 channel has been described. KPLBS leads to severe developmental and intellectual problems, microcephaly, tightly adherent skin and severe generalized lipodystrophy. Recent breakthroughs in x-ray crystallography and cryo-electron microscopy provide insights into the structure of inward rectifier channels, and enable detailed characterization of the structural effects of disease-causing mutations. Multi-µs time scale molecular dynamics simulations on the WT Kir3.2 and disease mutant channel provide insights into the structural changes, caused by the point mutation, and the molecular mechanisms, leading to loss of K+ selectivity.

Altered acylated ghrelin response to food intake in congenital generalized lipodystrophy.

BackgroundPatients with congenital generalized lipodystrophy (CGL) have very low levels of leptin and are described as having a voracious appetite. However, a direct comparison between CGL and eutrophic individuals is lacking, regarding both appetite parameters and acylated ghrelin, the hormone form that is active in acute food intake stimulation. The objective of the present study was to address whether and in what extent the subjective appetite parameters and acylated ghrelin response to a meal are affected in CGL individuals, in comparison to eutrophic individuals. Additionally, an obese group was included in the study, to allow the comparison between a leptin-resistant and a leptin-deficient condition on these aspects.MethodsEutrophic controls (EUT, n = 10), obese subjects (OB, n = 10) and CGL (n = 11) were fasted overnight and then received an ad libitum meal. Blood was collected and the visual analogue scale was applied before and 90 minutes after the meal. An additional blood sample was collected at 60 minutes for ghrelin determination.ResultsThe CGL patients showed low fasting levels of leptin and adiponectin, dyslipidemia, and insulin resistance. The caloric intake was similar among the 3 groups. However, both CGL (p = 0.02) and OB (p = 0.04) had shorter satiation times than EUT. The CGL patients also had lower satiety time (p = 0.01) and their sensation of hunger was less attenuated by the meal (p = 0.03). Fasting acylated ghrelin levels were lower in CGL than in EUT (p = 0.003). After the meal, the levels tended to decrease in EUT but not in CGL and OB individuals.ConclusionThe data indicate that, although not hyperphagic, the CGL patients present appetite disturbances in relation to eutrophic individuals. Their low fasting levels of acylated ghrelin and the absence of the physiological drop after meal intake suggest a role of these disturbances in hunger attenuation and satiety but not in acute satiation.

Berardinelli-Seip Congenital Lipodystrophy in a Filipino Child

Berardinelli-Seip Congenital Lipodystrophy (BSCL) is an autosomal recessive inborn error of the common pathway of acylglycerol and phospholipid synthesis. Patients with this condition present with generalized lipoatrophy, hepatomegaly, acromegalic features, hypertrichosis, and developmental delay. But on workup, they may also be discovered to have hypertriglyceridemia with or without hypercholesterolemia and insulin resistance. A high index of suspicion is required for diagnosis which may have implications in management. Here we present a 5-year old male with clinical features of BSCL. BSCL2 gene sequencing done showed a homozygous c.782dupG, p.(Ile262Hisfs*12) sequence alteration, classified as pathogenic, hence, confirming the diagnosis of BSCL. This is the first reported case in the Philippines.

Lipodistrofia Congénita Generalizada. Informe de caso

La Lipodistrofia Congénita Generalizada o síndrome de Berardinelli – Seip, es un trastorno autosómico recesivo, con baja prevalencia a nivel mundial. Se caracteriza por lipoatrofia, características acromegaloides, hepatomegalia, hipertrigliceridemia, insulinorresistencia (criterios principales); miocardiopatía hipertrófica, deterioro intelectual, hirsutismo, pubertad precoz, quistes óseos, flebomegalia (criterios menores). Ésta patología se clasifica en 4 tipos, de acuerdo al gen alterado y por algunos síntomas característicos adicionales; tipo 1 (gen AGPAT2); tipo 2 (gen BSCL2); tipo 3 (gen CAV1); y tipo 4 (gen PTRF). Se realiza el abordaje de una adolescente que clínicamente cumple criterios clínicos diagnósticos, es necesario la verificación diagnóstica genética.

SEIPIN: A Key Factor for Nuclear Lipid Droplet Generation and Lipid Homeostasis.

Lipid homeostasis is essential for normal cell physiology. Generally, lipids are stored in a lipid droplet (LD), a ubiquitous organelle consisting of a neutral lipid core and a single layer of phospholipid membrane. It is thought that LDs are generated from the endoplasmic reticulum and then released into the cytosol. Recent studies indicate that LDs can exist in the nucleus, where they play an important role in the maintenance of cell phospholipid homeostasis. However, the details of nuclear lipid droplet (nLD) generation have not yet been clearly characterized. SEIPIN is a nonenzymatic protein encoded by the Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) gene. It is associated with lipodystrophy diseases. Many recent studies have indicated that SEIPIN is essential for LDs generation. Here, we review much of this research in an attempt to explain the role of SEIPIN in nLD generation. From an integrative perspective, we conclude by proposing a theoretical model to explain how SEIPIN might participate in maintaining homeostasis of lipid metabolism.