Diagnosis of Congenital and Acquired Generalized Lipodystrophies—Similarities and Differences

Lipodystrophies are characterized by selective but variable loss of body fat and metabolic complications of insulin resistance. We hypothesized that reduced synthesis and secretion of adipocyte-specific proteins may be related to the metabolic complications of lipodystrophy. Therefore, we compared fasting serum concentrations of adiponectin and leptin, in 18 patients with congenital generalized lipodystrophy (CGL), 11 with acquired generalized lipodystrophy (AGL), 46 with familial partial lipodystrophy-Dunnigan variety (FPLD) and 18 with acquired partial lipodystrophy (APL) and studied their relationship to metabolic parameters. Patients with CGL and AGL had markedly reduced serum adiponectin levels compared to those with FPLD and APL (median [range]: 1.5 [0.4-7.5], 3.2 [0.6-7.7], 6.9 [1.9-23.2] and 7.9 [3.1-13.3] microg/mL, respectively, p < 0.0001); the same trend was noted for serum leptin levels (0.63 [0.05-3.7], 2.18 [0.05-11.30], 2.86 [0.23-9.00] and 6.24 [1.21-10.4] ng/mL, respectively, p < 0.0001). Serum adiponectin levels correlated negatively with fasting serum triglycerides (r = -0.6, p < 0.001) and insulin levels (r = -0.5, p < 0.0001) and positively with serum high-density lipoprotein cholesterol levels (r = 0.5, p < 0.001). Serum adiponectin levels were lower in patients with diabetes compared to non-diabetic subjects (3.0 vs. 7.1 microg/mL, p < 0.001). Our results indicate that serum adiponectin and leptin levels are extremely low in patients with generalized lipodystrophies and may be related to severe insulin resistance and its metabolic complications in lipodystrophies.

Congenital generalized lipodystrophy (CGL) is an autosomal recessive disorder with two major subtypes. Variants in AGPAT2 result in CGL type 1 with milder manifestations, whereas BSCL2 variants cause CGL type 2 with more severe features. Muscle hypertrophy caused by lack of adipose tissue is present early in life in CGL patients. Our aim was to investigate 10 CGL patients from 7 different countries and report genotype-phenotype relationships. Genetic analysis identified disease-causing variants in AGPAT2 (five patients) and in BSCL2 (five patients), including three novel variants; c.134C>A (p.Ser45*), c.216C>G (p.Tyr72*) in AGPAT2 and c.458C>A (p.Ser153*) in BSCL2. We also report possible novel clinical features such as anemia, breast enlargement, steatorrhea, intraventricular hemorrhage and nephrolithiasis in CGL patients. Generalized lipodystrophy and muscular hypertrophy were the only features in all of our patients. Hepatomegaly was the second common feature. Some manifestations were exclusively noticed in our CGL2 patients; hypertrichosis, high-pitched voice and umbilical hernia. Bone cysts and history of seizures were noticed only in CGL1 patients. The findings of this study expand our knowledge of genotype-phenotype correlations in CGL patients. These results have important clinical applications in diagnosis and management of the CGL patients as well as in genetic counseling in families at-risk.

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.

Plasma signatures of Congenital Generalized Lipodystrophy patients identified by untargeted lipidomic profiling are not changed after a fat-containing breakfast meal

BackgroundPrevious studies suggest intestinal dysbiosis is associated with metabolic diseases. However, the causal relationship between them is not fully elucidated. Gut microbiota evaluation of patients with congenital generalized lipodystrophy (CGL), a disease characterized by the absence of subcutaneous adipose tissue, insulin resistance, and diabetes since the first years of life, could provide insights into these relationships.MethodsA cross-sectional study was conducted with patients with CGL (n = 17) and healthy individuals (n = 17). The gut microbiome study was performed by sequencing the 16S rRNA gene through High-Throughput Sequencing (BiomeHub Biotechnologies, Brazil).ResultsThe median age was 20.0 years old, and 64.7% were female. There was no difference between groups in pubertal stage, BMI, ethnicity, origin (rural or urban), delivery, breastfeeding, caloric intake, macronutrient, or fiber consumption. Lipodystrophic patients presented a lower alpha diversity (Richness index: 54.0 versus 67.5; p = 0.008). No differences were observed in the diversity parameters when analyzing the presence of diabetes, its complications, or the CGL subtype.ConclusionIn this study, we demonstrate for the first time a reduced gut microbiota diversity in individuals with CGL. Dysbiosis was present despite dietary treatment and was also observed in young patients. Our findings allow us to speculate that the loss of intestinal microbiota diversity may be due to metabolic abnormalities present since the first years of life in CGL. Longitudinal studies are needed to confirm these findings, clarifying the possible causal link between dysbiosis and insulin resistance in humans.

This study was designed to assess cardiac autonomic regulation in congenital generalized lipodystrophy (CGL) patients using 24 h heart rate variability (HRV). A cross-sectional study was carried out to evaluate 18 patients with CGL and 19 healthy controls matched by sex and age. We measured blood pressure, plasma concentrations of glucose, triglycerides, cholesterol, high-density lipoprotein-cholesterol, insulin resistance by the homeostatic model assessment (HOMA-R), left ventricular mass (LVM) (by two-dimensional echocardiography), and 24 h HRV (by the time domain indices MeanRR, SDNN, and rMSSD). Compared with controls, CGL patients had higher blood pressure (systolic, 131.1 vs. 106.3 mmHg, P < 0.05; diastolic, 85.0 vs. 68.2 mmHg, P < 0.05) and 10 patients met criteria for arterial hypertension and concentric left ventricular hypertrophy (LVM index > or =115 g/m(2)and relative left ventricular wall thickness > or =0.42). Patients with CGL had higher levels of glucose, triglycerides, cholesterol, and HOMA-R and 12 met criteria for type 2 diabetes mellitus. Compared with controls, CGL patients had lower MeanRR (639.8 vs. 780.5 ms, P < 0.001), SDNN (79.2 vs. 168.5 ms, P < 0.001), and rMSSD (15.8 vs. 59.6 ms, P < 0.001). In CGL patients, the reduction in HRV was independent of the metabolic and haemodynamic disturbances. Congenital generalized lipodystrophy patients have abnormal autonomic modulation, reflected by increased heart rate and pronounced reduction in HRV, independent of the metabolic and haemodynamic disturbances observed in this disorder.

Previous studies have suggested that Retinol Binding Protein 4 (RPB4), a protein produced by the adipose tissue, is associated with insulin resistance (IR). Congenital Generalized Lipodystrophy (CGL) is a rare disease characterized by IR and paucity of adipose tissue. Our objective was to determine RBP4 levels in patients with CGL. Six (6) patients with CGL and a healthy control group were selected to participate in the study. Anthropometric and biochemical variables were compared between groups. No difference was observed in RBP4 levels between the two groups (CGL 42.5 [12.5 - 127] vs. control 57.4 [15.9 - 165]; p = 0.78). On the other hand, leptin levels were significantly lower in CGL patients (CGL 0.65 [0.2 - 0.7] vs. control 10.9 [0.9 - 38.6]; p = 0.015). No correlation was found between RBP-4 and waist circunference (r = 0.18, p = 0.57), or BMI (r = 0.24, p = 0.45). RBP4 is not decreased in CGL. These results suggest that adipose tissue may not be the main source of RBP4.

Congenital generalized lipodystrophy (CGL), Berardinelli-Seip syndrome, is a rare autosomal recessive disorder characterized by the generalized absence of adipose tissue at birth, severe insulin resistance early in life, hypertriglyceridemia, hepatomegaly, and the development of diabetes mellitus during puberty. Recently, two genes, BSCL2 and AGPAT2, were identified as causative genes for CGL. It has been reported that patients with BSCL mutations present with more severe clinical findings than those with AGPAT2 mutations. However, the clinical course of CGL caused by BSCL2 mutations in infancy has not been fully elucidated. Two Japanese infantile patients with CGL from independent families were examined and underwent an oral glucose tolerance test. Insulin resistance and insulin secretion were estimated using the homeostasis model assessment for insulin resistance and the insulinogenic index, respectively. Sequence analysis of the entire coding region of BSCL2 and AGPAT2 was performed. Both CGL patients presented with normal glycemic profiles after oral glucose tolerance tests; however, the values from the homeostasis model assessment of insulin resistance were elevated and well above the cut-off point for diagnosis of infant insulin resistance in both patients. One patient possessed a known homozygous nonsense mutation in exon 8 (c.823C>T) of BSCL2; the other had a novel homozygous missense mutation in exon 5 (c.560A>G) of BSCL2. Japanese CGL patients with BSCL2 mutations presented with severe insulin resistance, even during infancy, prior to the development of diabetes mellitus.

Congenital generalized lipodystrophy (CGL) is an autosomal recessive genetic disorder characterized by almost complete absence of adipose tissue, muscular appearance, and severe insulin resistance since birth. We investigated whether insulin resistance in CGL patients is associated with abnormal muscle morphology and whether increased muscularity imparts increased muscle strength and exercise capacity We obtained quadriceps muscle biopsies to study muscle fiber types and capillary density in three African-American women (aged 17-20 years) with CGL. We also assessed quadriceps muscle strength, muscle metabolism, and maximal O2 consumption in the patients. Quadriceps muscle biopsies revealed a markedly higher percentage of type II (fast-twitch glycolytic) muscle fibers in patients with CGL versus sedentary young women (75-78 vs. 47-57%, respectively). The capillary-to-fiber ratio (2.7-3.0), however, was normal. Cross-sectional areas of type I (slow-twitch oxidative) (1,262-2,685 microm2) and type II (2,304-3,594 microm2) fibers were far below the normal values (3,811-4,310 and 3,115-4,193 microm2, respectively), suggesting muscle hyperplasia but not hypertrophy The quadriceps muscle strength, as measured by Cybex, was below average; the maximal O2 consumption (23-32 ml x kg(-1) x min(-1)) was also below average. 31P nuclear magnetic resonance spectroscopy of the forearm muscles revealed normal pH and metabolic responses to static and dynamic exercises. We conclude that insulin resistance in patients with CGL is associated with an increased proportion of type II muscle fibers but not reduced capillary density. Increased muscularity in CGL is due to muscle hyperplasia and is not associated with increased muscle strength.

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by near-total lack of body fat. We aimed to study natural history and disease burden of various subtypes of CGL. We attempted to ascertain nearly all patients with CGL in Turkey. This was a nationwide study. Participants included 33 patients (22 families) with CGL and 30 healthy controls. We wanted to ascertain genotypes by sequencing of the known genes. Whole-body magnetic resonance imaging was used to investigate the extent of fat loss. Metabolic abnormalities and end-organ complications were measured on prospective follow-up. Analysis of the AGPAT2 gene revealed four previously reported and four novel mutations (CGL1; c.144C>A, c.667_705delinsCTGCG, c.268delC, and c.316+1G>T). Analysis of the BSCL2 gene revealed four different homozygous and one compound heterozygous possible disease-causing mutations (CGL2), including four novel mutations (c.280C>T, c.631delG, c.62A>T, and c.465-468delGACT). Two homozygous PTRF mutations (c.481-482insGTGA and c.259C>T) were identified (CGL4). Patients with CGL1 had preservation of adipose tissue in the palms, soles, scalp, and orbital region, and had relatively lower serum adiponectin levels as compared to CGL2 patients. CGL4 patients had myopathy and other distinct clinical features. All patients developed various metabolic abnormalities associated with insulin resistance. Hepatic involvement was more severe in CGL2. End-organ complications were observed at young ages. Two patients died at age 62 years from cardiovascular events. CGL patients from Turkey had both previously reported and novel mutations of the AGPAT2, BSCL2, and PTRF genes. Our study highlights the early onset of severe metabolic abnormalities and increased risk of end-organ complications in patients with CGL.

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.

Congenital generalized lipodystrophy (CGL) is an autosomal recessive metabolic syndrome with involvement of multiple organs. Mutations in BSCL2 are known to be associated with a severe form of CGL and mental retardation (MR). The genetic heterogeneity in CGL patients is accompanied by phenotypic heterogeneity in different ethnic groups. Studies in the Indian context are very few in this regard. We report here a detailed clinical analysis of a CGL case from infancy to adult hood. Interestingly, the patient was found to be homozygous for a novel BSCL2 mutation, but with normal intellectual development contrasting with the MR associated with BSCL2 mutation in CGL patients. The biochemical investigations at the time of diagnosis (9 months) included total cholesterol, total lipids, triglycerides, phospholipids, β-lipoprotein and free fatty acids, which were above normal limits. The clinical phenotype, viz. lack of subcutaneous fat, hepatosplenomegaly, cardiomegaly, and advanced bone age was also documented. The patient was found to be insulin resistant and diabetes mellitus was diagnosed by age 13 years. Ultrasonography of the ovaries at age 22 showed polycystic features with elevated levels of gonadotropins and negligible levels of serum leptin. For genetic analysis, direct DNA sequencing of BSCL2 was carried out and disclosed an 11-base-pair deletion in exon 6 (H217fsX272) resulting in a truncated protein. This is a novel mutation that contributes to CGL formation in a family of Indian origin and adds to the array of variants reported in this disorder. Moreover, the novel mutation is found to be associated with normal intellectual ability.

Congenital generalized lipodystrophy (CGL), Berardinelli-Seip syndrome, is a rare metabolic disorder characterized by a near total lack of adipose tissue from birth or early infancy. Recently, seipin, encoding a 398-amino acid protein of unknown function, and AGPAT2, encoding 1-acyl-sn-glycerol-3-phosphate acyltransferase 2, were identified as causative genes for CGL. Seipin mutations were found in patients from families originating from Europe and the Middle East. AGPAT2 mutations were found predominantly in African ancestry. However, no information is available on these genes in the pathogenesis of CGL in Asian ancestry. We examined the sequences of the entire coding region of seipin and AGPAT2 in four Japanese CGL patients from independent families. Their average body fat content was 4.7 +/- 0.5%, and the plasma leptin level was 1.15 +/- 0.14 ng/ml. We identified a novel nonsense mutation of seipin at codon 275 (R275X). Of four CGL patients, three were homozygous for R275X. No seipin mutation was found in any exon in one patient. We did not find any AGPAT2 mutations in our Japanese patients, suggesting that AGPAT2 is a minor causative gene, if any, for CGL in Japanese. This is the first report on gene and phenotype analysis of CGL in Japanese.

High levels of triglycerides and free fatty acids have been implicated in the pathogenesis of type 2 diabetes mellitus (DM). Congenital generalized lipodystrophy (CGL) is an autosomal recessive syndrome characterized by intense whole body reduction of subcutaneous fat. Its clinical manifestations appear during the first years of life. However, DM is usually a late event. We report a patient with CGL, diagnosed at 4 months of age, who has severe hypertriglyceridemia (serum triglyceride 12.34 mmol/l and cholesterol 3.90 mmol/l), muscular hypertrophy, hepatomegaly and DM (fasting glycemia 25.9 mmol/l). Hepatic biopsy revealed steatosis and fibrosis. A modified normolipidic (composed of medium chain triglycerides) normocaloric normoproteic milky diet and insulin therapy were instituted. After 1 month treatment a reduction of serum glucose and triglyceride levels (4.13 mmol/I and 7.7 mmol/l, respectively) was noted, with later normalization, which led to the discontinuation of insulin therapy. The patient has been maintaining good control with diet alone, presenting normal serum lipid levels (triglycerides 1.07 mmol/l, total cholesterol 2.71 mmol/l) and the following glycemic profile at OGTT: 0' 4.4 mmol/l; 30' 7.0 mmol/l; 60' 3.8 mmol/l; 90' 5.3 mmol/l, and 120' 5.2 mmol/l. The disappearance of hepatic steatosis was evidenced by a biopsy obtained 1 year after the beginning of treatment. In conolusion, this report suggests that the DM occurring in CGL can be precipitated by high triglyceride levels.

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.