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Context Despite several reports of familial partial lipodystrophy (FPLD) type 2 (FPLD2) due to heterozygous LMNA variants and FPLD3 due to PPARG variants, the phenotypic differences among them remain unclear. Objective To compare the body fat distribution, metabolic parameters, and prevalence of metabolic complications between FPLD3 and FPLD2. Methods A retrospective, cross-sectional comparison of patients from 2 tertiary referral centers—UT Southwestern Medical Center and the National Institute of Diabetes and Digestive and Kidney Diseases. A total of 196 females and 59 males with FPLD2 (age 2-86 years) and 28 females and 4 males with FPLD3 (age 9-72 years) were included. The main outcome measures were skinfold thickness, regional body fat by dual-energy X-ray absorptiometry (DXA), metabolic variables, and prevalence of diabetes mellitus and hypertriglyceridemia. Results Compared with subjects with FPLD2, subjects with FPLD3 had significantly increased prevalence of hypertriglyceridemia (66% vs 84%) and diabetes (44% vs 72%); and had higher median fasting serum triglycerides (208 vs 255 mg/dL), and mean hemoglobin A1c (6.4% vs 7.5%). Compared with subjects with FPLD2, subjects with FPLD3 also had significantly higher mean upper limb fat (21% vs 27%) and lower limb fat (16% vs 21%) on DXA and increased median skinfold thickness at the anterior thigh (5.8 vs 11.3 mm), calf (4 vs 6 mm), triceps (5.5 vs 7.5 mm), and biceps (4.3 vs 6.8 mm). Conclusion Compared with subjects with FPLD2, subjects with FPLD3 have milder lipodystrophy but develop more severe metabolic complications, suggesting that the remaining adipose tissue in subjects with FPLD3 may be dysfunctional or those with mild metabolic disease are underrecognized.

Acquired lipodystrophy is often characterized as an idiopathic subtype of lipodystrophy. Despite suspicion of an immune-mediated pathology, biomarkers such as autoantibodies are generally lacking. Here, we used an unbiased proteome-wide screening approach to identify autoantibodies to the adipocyte-specific lipid droplet protein Perilipin-1 (PLIN1) in a murine model of Autoimmune Polyendocrine Syndrome 1 (APS1). We then tested for PLIN1 autoantibodies in human subjects with acquired lipodystrophy with two independent severe breaks in immune tolerance (including APS1) along with controls using a specific Radioligand Binding Assay and indirect immunofluorescence on fat tissue. We identified autoantibodies to PLIN1 in these two cases, including the first reported case of APS1 with acquired lipodystrophy and a second patient who acquired lipodystrophy as an immune-related adverse event following cancer immunotherapy. Lastly, we also found PLIN1 autoantibodies to be specifically enriched in a subset of patients with acquired generalized lipodystrophy (17/46; 37%) particularly those with panniculitis and other features of autoimmunity. These data lend additional support to new literature that suggests that PLIN1 autoantibodies represent a marker of acquired autoimmune lipodystrophies and further link them to a break in immune tolerance.

Context Congenital generalized lipodystrophy, type 1 (CGL1), due to biallelic pathogenic variants in AGPAT2, is characterized by the near total loss of body fat from the face, trunk, and extremities. Patients develop premature diabetes, hypertriglyceridemia, hepatic steatosis, and polycystic ovary syndrome. However, sparing of the facial fat and precocious pubertal development has not been previously reported in CGL1. Case Description We report a 21-year-old woman of European descent with CGL1 who had sparing of the facial fat and premature thelarche at birth with premature pubarche and menstrual bleeding at age 3 years. Her serum 17-OH progesterone level rose to 1000 ng/dL (30.26 nmol/L) after cosyntropin stimulation test, suggestive of nonclassical congenital adrenal hyperplasia (NCAH) due to 21-hydroxylase deficiency. Hydrocortisone replacement therapy from age 3.5 to 10 years resulted in cessation of menstruation and growth of pubic hair, and a reduction of breast size. Sanger and whole-exome sequencing revealed compound heterozygous variants c.493-1G>C; p.(Leu165_Gln196del), and c.del366_588+534; p.(Leu123Cysfs*55) in AGPAT2 plus c.806G>C; p.(Ser269Thr) and c.844G>T; p.(Val282Leu) in CYP21A2. She developed diabetes at age 13 requiring high-dose insulin and had 7 episodes of acute pancreatitis due to extreme hypertriglyceridemia in the next 5 years. Metreleptin therapy was initiated at age 18 and after 3 years, she had remission of diabetes and hypertriglyceridemia; however, menstrual irregularity and severe hirsutism did not improve. Conclusion Concomitant NCAH in this CGL1 patient was associated with precocious pubertal development and sparing of facial fat. Metreleptin therapy drastically improved her hyperglycemia and hyperlipidemia but not menstrual irregularity and hirsutism.

Pulmonary tuberculosis has diverse clinical presentations. Cysts in the lung can arise due to large number of causes out of which tuberculosis is very rare. We report two immunocompetent cases of pulmonary tuberculosis who presented with multiple cysts in the lung parenchyma. The diagnosis was confirmed by the transbronchial lung cryobiopsy in first case and by analysis of bronchoalveolar lavage fluid in the second. Both had spontaneous pneumothorax which was treated with chest drain and pleurodesis. Both showed an excellent response to anti-tubercular therapy and steroids. Tuberculosis presenting as cystic lung disease is atypical and rare.

Context Familial partial lipodystrophy, Dunnigan variety (FPLD2) is a rare autosomal dominant disorder resulting from LMNA causal variants, which is characterized by loss of subcutaneous fat from the extremities and predisposition to metabolic complications. The diagnostic value of various anthropometric measurements for FPLD2 remains unknown. Objective To determine specificity and sensitivity of anthropometric measurements for the diagnosis of FPLD2. Methods We measured skinfold thickness and regional body fat by dual energy X-ray absorptiometry (DXA) in 50 adult females and 6 males with FPLD2 at UT Southwestern and compared their data with the sex- and age-matched controls from the National Health and Nutrition Examination Survey (NHANES) 1999-2010. We further compared data from 1652 unaffected females from the Dallas Heart Study and 23 females with FPLD2 from the National Institutes of Health with the NHANES data. Results The DXA-derived lower limb fat (%) had the best specificity (0.995) and sensitivity (1.0) compared with the upper limb fat, truncal fat, the ratio of lower limb to truncal fat, and triceps skinfold thickness for adult females with FPLD2. The lower limb fat below 1st percentile of NHANES females had a false-positive rate of 0.0054 and a false negative rate of 0. The diagnostic value of anthropometric parameters could not be determined for males with FPLD2 due to small sample size. Conclusions The lower limb fat (%) is the best objective anthropometric measure for diagnosing FPLD2 in females. Women with below the 1st percentile lower limb fat should undergo genetic testing for FPLD2, especially if they have metabolic complications.

BackgroundDespite major advances in understanding the molecular basis of various genetic lipodystrophy syndromes, some rare patients still remain unexplained.CasesWe report a novel autosomal recessive lipodystrophy affecting two sisters aged 17 and 19 years and characterised by early onset intellectual disability, and subsequent development of near-generalised loss of subcutaneous fat with diabetes mellitus, extreme hypertriglyceridemia, hepatic steatosis, short stature, clinodactyly, joint contractures, leiomyoma of uterus and cataracts in childhood. The lipodystrophy was more pronounced in the upper and lower extremities, and there was no associated muscular hypertrophy. Using whole exome sequencing in this consanguineous Hispanic pedigree, we report disease-causing homozygous p.Arg545His LMNA variant in the affected subjects, and confirm the lack of pathogenic variants in other known lipodystrophy genes. The mother and a younger brother were both heterozygous for p.Arg545His LMNA variant and were overweight with acanthosis nigricans without any evidence of lipodystrophy. Our patients are distinct from previously reported autosomal recessive lipodystrophy syndromes and have no overlap with other autosomal recessive laminopathies, including mandibuloacral dysplasia, Emery-Dreifuss muscular dystrophy and Charcot-Marie-Tooth neuropathy.ConclusionOur report of this unusual familial generalised lipodystrophy syndrome adds to the pleiotropy associated with biallelic autosomal recessive LMNA variants.

Loss of dysferlin (DYSF) protein in humans results in limb-girdle muscular dystrophy 2B, characterized by progressive loss of muscles in the distal limbs with impaired locomotion. The DYSF-null (Bla/J) mouse develops severe steatotic muscles upon aging. Here, we report a marked increase in adipocytes, especially in the psoas and gluteus muscles but not in the soleus and tibialis anterior muscles in aged Bla/J mice compared with WT mice. There was a robust upregulation in the mRNA expression of enzymes involved in lipogenesis and triacylglycerol (TAG) synthesis pathways in the steatotic skeletal muscles. Lipidomic analysis of the steatotic skeletal muscles revealed an increase in several molecular species of TAG, although it is unclear whether it was at the expense of phosphatidylcholine and phosphatidylserine. The adipocytes in steatotic muscles were extramyocellular, as determined by the increased expression of caveolin 1 (a cellular marker for adipocytes) and lipid-droplet protein, perilipin 1. This increase in adipocytes occured as a consequence of the loss of myocytes.

Multiple genetic loci have been reported for progeroid syndromes. However, the molecular defects in some extremely rare forms of progeria have yet to be elucidated. Here, we report a 21-year-old man of Chinese ancestry who has an autosomal recessive form of progeria, characterized by severe dwarfism, mandibular hypoplasia, hyperopia, and partial lipodystrophy. Analyses of exome sequencing data from the entire family revealed only 1 rare homozygous missense variant (c.86CT; p.Pro29Leu) in TOMM7 in the proband, while the parents and 2 unaffected siblings were heterozygous for the variant. TOMM7, a nuclear gene, encodes a translocase in the outer mitochondrial membrane. The TOMM complex makes up the outer membrane pore, which is responsible for importing many preproteins into the mitochondria. A proteomic comparison of mitochondria from control and proband-derived cultured fibroblasts revealed an increase in abundance of several proteins involved in oxidative phosphorylation, as well as a reduction in abundance of proteins involved in phospholipid metabolism. We also observed elevated basal and maximal oxygen consumption rates in the fibroblasts from the proband as compared with control fibroblasts. We concluded that altered mitochondrial protein import due to biallelic loss-of-function TOMM7 can cause severe growth retardation and progeroid features.

Context Patients with very severe hypertriglyceridemia (triglyceride levels ≥2000 mg/dL; 22.6 mmol/L) require aggressive treatment. However, little research exists on the underlying etiologies and management of very severe hypertriglyceridemia. Objective We hypothesized (i) very severe hypertriglyceridemia in adults is mostly associated with secondary causes and (ii) most patients with very severe hypertriglyceridemia lack appropriate follow-up and treatment. Design We queried electronic medical records at Parkland Health and Hospital Systems for lipid measurements in the year 2016 and identified patients with serum triglyceride levels ≥2000 mg/dL (22.6 mmol/L). We extracted data on demographics, underlying causes, lipid-lowering therapy, and follow-up. Results One hundred sixty-four serum triglyceride measurements were ≥2000 mg/dL (22.6 mmol/L) in 103 unique patients. Of these, 60 patients were admitted to the hospital (39 for acute pancreatitis). Most were Hispanic (79%). The major conditions associated with very severe hypertriglyceridemia included uncontrolled diabetes mellitus (74%), heavy alcohol use (10%), medication use (7%), and hypothyroidism (2%). Two patients were known to have monogenic causes of hypertriglyceridemia. After the index measurement of triglycerides ≥2000 mg/dL (22.6 mmol/L), the use of triglyceride-lowering drugs increased, most prominently the use of fish oil supplements, which increased by 80%. However, in follow-up visits, hypertriglyceridemia was addressed in only 50% of encounters, and serum triglycerides were remeasured in only 18%. Conclusion In summary, very severe hypertriglyceridemia was quite prevalent (∼0.1% of all lipid measurements) in our large county health care system, especially in Hispanic men. Most cases were related to uncontrolled diabetes mellitus, and follow-up monitoring was inadequate.

Lipodystrophies are rare, heterogeneous, genetic or acquired, disorders characterised by varying degrees of body fat loss and associated metabolic complications, including insulin resistance, dyslipidaemias, hepatic steatosis and predisposition to atherosclerotic vascular disease. The four main types of lipodystrophy, excluding antiretroviral therapy-induced lipodystrophy in HIV-infected patients, are congenital generalised lipodystrophy (CGL), familial partial lipodystrophy (FPLD), acquired generalised lipodystrophy (AGL) and acquired partial lipodystrophy (APL). This paper reviews the literature related to the prevalence of dyslipidaemias and atherosclerotic vascular disease in patients with lipodystrophies. Patients with CGL, AGL and FPLD have increased prevalence of dyslipidaemia but not those with APL. Patients with CGL as well as AGL present in childhood, and have severe dyslipidaemias (mainly hypertriglyceridaemia) and early onset diabetes mellitus as a consequence of extreme fat loss. However, only a few patients with CGL and AGL have been reported to develop coronary heart disease. In contrast, data from some small cohorts of FPLD patients reveal increased prevalence of atherosclerotic vascular disease especially among women. Patients with APL have a relatively low prevalence of hypertriglyceridaemia and diabetes mellitus. Overall, patients with lipodystrophies appear to be at high risk of atherosclerotic vascular disease due to increased prevalence of dyslipidaemia and diabetes and efforts should be made to manage these metabolic complications aggressively to prevent atherosclerotic vascular disease.

Wiedemann-Rautenstrauch syndrome (WRS), also known as neonatal progeroid syndrome, is a rare disorder of unknown etiology. It has been proposed to be autosomal-recessive and is characterized by variable clinical features, such as intrauterine growth restriction and poor postnatal weight gain, characteristic facial features (triangular appearance to the face, convex nasal profile or pinched nose, and small mouth), widened fontanelles, pseudohydrocephalus, prominent scalp veins, lipodystrophy, and teeth abnormalities. A previous report described a single WRS patient with bi-allelic truncating and splicing variants in POLR3A. Here we present seven additional infants, children, and adults with WRS and bi-allelic truncating and/or splicing variants in POLR3A. POLR3A, the largest subunit of RNA polymerase III, is a DNA-directed RNA polymerase that transcribes many small noncoding RNAs that regulate transcription, RNA processing, and translation. Bi-allelic missense variants in POLR3A have been associated with phenotypes distinct from WRS: hypogonadotropic hypogonadism and hypomyelinating leukodystrophy with or without oligodontia. Our findings confirm the association of bi-allelic POLR3A variants with WRS, expand the clinical phenotype of WRS, and suggest specific POLR3A genotypes associated with WRS and hypomyelinating leukodystrophy.

Context Congenital generalized lipodystrophy, type 4 (CGL4) is a rare autosomal recessive disorder caused by mutations in caveolae-associated protein 1. Patients with CGL4 also have myopathy and cardiomyopathy with a predisposition for sudden death due to ventricular arrhythmias. However, the underlying pathology for these morbidities remains unknown. Therefore, we report on an autopsy of a Hispanic boy with CGL4. Case Description Our patient had early-onset generalized lipodystrophy, feeding difficulties, myopathy, atlanto-axial dislocation, and learning disabilities. He was diagnosed with catecholaminergic polymorphic ventricular tachycardia (CPVT) at age 8 years, had poor compliance with medications, and died suddenly at age 15.3 years. Autopsy showed marked loss of subcutaneous and omental fat with no inflammatory cells in adipose tissue and normal adipocytes in the parathyroid glands. There were adipocytes interdigitating cardiac muscle fibers, with fibro-fatty infiltration in the right ventricle, near coronary sinus, and atrioventricular node. There was no evidence of coronary heart disease. The quadriceps femoris muscle did not show adipocyte infiltration, inflammation, or fibrosis. The muscularis mucosa layer was thickened in the esophagus and at the gastro-duodenal junction, and the esophagus had prominent, large nerves in the subserosa. The liver weighed 3000 g, with minimal chronic inflammation and steatosis in 40% of parenchyma, primarily in zones 2 and 3. There was no spermatogenesis in the spermatic tubules. Conclusions Our data suggest that fibro-fatty infiltration of the right ventricle may contribute to CPVT in patients with CGL4. Thick muscularis mucosa and large nerves in the esophagus likely contributed to dysphagia and dysmotility. A lack of spermatids suggests infertility in affected male patients.

Diabetes mellitus (DM) in children is most often caused by impaired insulin secretion (type 1 DM). In some children, the underlying mechanism for DM is increased insulin resistance, which can have different underlying causes. While the majority of these children require insulin dosages less than 2.0 U/kg/day to achieve normoglycemia, higher insulin requirements indicate severe insulin resistance. Considering the therapeutic challenges in patients with severe insulin resistance, early diagnosis of the underlying cause is essential in order to consider targeted therapies and to prevent diabetic complications. Although rare, several disorders can attribute to severe insulin resistance in pediatric patients. Most of these disorders are diagnosed through advanced diagnostic tests, which are not commonly available in low- or middle-income countries. Based on a case of DM with severe insulin resistance in a Surinamese adolescent who was later confirmed to have autosomal recessive congenital generalized lipodystrophy, type 1 (Berardinelli–Seip syndrome), we provide a systematic approach to the differential diagnosis and work-up. We show that a thorough review of medical history and physical examination generally provide sufficient information to diagnose a child with insulin-resistant DM correctly, and, therefore, our approach is especially applicable to low- or middle-income countries.

Background Adipocytes from lipodystrophic Agpat2−/− mice have impaired adipogenesis and fewer caveolae. Herein, we examined whether these defects are associated with changes in lipid composition or abnormal levels of caveolae-associated proteins. Lipidome changes were quantified in differentiated Agpat2−/− adipocytes to identify lipids with potential adipogenic roles. Methods Agpat2−/− and wild type brown preadipocytes were differentiated in vitro. Plasma membrane was purified by ultracentrifugation. Number of caveolae and caveolae-associated proteins, as well as sterol, sphingolipid, and phospholipid lipidome were determined across differentiation. Results Differentiated Agpat2−/− adipocytes had decreased caveolae number but conserved insulin signaling. Caveolin-1 and cavin-1 levels were equivalent between Agpat2−/− and wild type adipocytes. No differences in PM cholesterol and sphingolipids abundance were detected between genotypes. Levels of phosphatidylserine at day 10 of differentiation were increased in Agpat2−/− adipocytes. Wild type adipocytes had increased whole cell triglyceride, diacylglycerol, phosphatidylglycerol, phosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine, and trihexosyl ceramide, and decreased 24,25-dihydrolanosterol and sitosterol, as a result of adipogenic differentiation. By contrast, adipogenesis did not modify whole cell neutral lipids but increased lysophosphatidylcholine, sphingomyelin, and trihexosyl ceramide levels in Agpat2−/− adipocytes. Unexpectedly, adipogenesis decreased PM levels of main phospholipids in both genotypes. Conclusion In Agpat2−/− adipocytes, decreased caveolae is not associated with changes in PM cholesterol nor sphingolipid levels; however, increased PM phosphatidylserine content may be implicated. Abnormal lipid composition is associated with the adipogenic abnormalities of Agpat2 −/− adipocytes but does not prevent insulin signaling.

Background Pathogenic variants in lamin A/C (LMNA) cause a variety of progeroid disorders including Hutchinson-Gilford progeria syndrome, mandibuloacral dysplasia, and atypical progeroid syndrome. Six families with 11 patients harboring a pathogenic heterozygous LMNA c.1045C>T; p.R349W variant have been previously reported to have partial lipodystrophy, cardiomyopathy, and focal segmental glomerulosclerosis (FSGS), suggesting a distinct progeroid syndrome. Methods We report 6 new patients with a heterozygous LMNA p.R349W variant and review the phenotype of previously reported patients to define their unique characteristics. We also performed functional studies on the skin fibroblasts of a patient to seek the underlying mechanisms of various clinical manifestations. Results Of the total 17 patients, all 14 adults with the heterozygous LMNA p.R349W variant had peculiar lipodystrophy affecting the face, extremities, palms, and soles with variable gain of subcutaneous truncal fat. All of them had proteinuric nephropathy with FSGS documented in 7 of them. Ten developed cardiomyopathy, and 2 of them died early at ages 33 and 45 years. Other common features included premature graying, alopecia, high-pitched voice, micrognathia, hearing loss, and scoliosis. Metabolic complications, including diabetes mellitus, hypertriglyceridemia, and hepatomegaly, were highly prevalent. This variant did not show any abnormal splicing, and no abnormal nuclear morphology was noted in the affected fibroblasts. Conclusions The heterozygous LMNA p.R349W variant in affected individuals has several distinct phenotypic features, and these patients should be classified as having multisystem progeroid syndrome (MSPS). MSPS patients should undergo careful assessment at symptom onset and yearly metabolic, renal, and cardiac evaluation because hyperglycemia, hypertriglyceridemia, FSGS, and cardiomyopathy cause major morbidity and mortality.

Context Despite considerable progress in elucidating the molecular basis of various progeroid syndromes, some rare patients remain unexplained. Objective To elucidate molecular genetic basis of a novel autosomal recessive progeroid syndrome. Participants A 24-year-old male and his 18-year-old sister with short stature, mandibular hypoplasia, pointed nose, shrill voice, severe osteoporosis, and short eyebrows and their unaffected siblings and parents belonging to a consanguineous Arab family. Results Using exome and Sanger sequencing, we report a novel homozygous p.Glu394Lys disease-causing variant in proline-rich transmembrane protein 3 (PRRT3). PRRT3 belongs to the family of proline-rich proteins containing several repeats of a short proline-rich sequence, but its function remains to be determined. Preliminary observations showing colocalization of Prrt3 and synaptophysin support its role in vesicle exocytosis. Consistent with the highest messenger ribonucleic acid expression of PRRT3 in the pituitary, both the patients had mild growth hormone deficiency but had near normal reproductive development. Conclusions We conclude that the homozygous p.Glu394Lys variant in PRRT3 may be associated with a novel autosomal recessive, progeroid syndrome with short stature, mandibular hypoplasia, osteoporosis, short eyebrows, and mild growth hormone (GH) deficiency. Our findings extend the spectrum of progeroid syndromes and elucidate important functions of PRRT3 in human biology, including secretion of GH from the pituitary.

Familial partial lipodystrophy (FPLD), a rare autosomal dominant disorder, is characterized by marked loss of subcutaneous (sc) fat from the extremities, and predisposition to insulin resistance, diabetes mellitus, dyslipidemia and hepatic steatosis. FPLD2 and FPLD3 due to causal variants in LMNA and PPARG, respectively, are the two most common subtypes. Due to extremely rare prevalence of FPLD3 and limited reports in the literature, whether there are phenotypic differences between the two subtypes remain unclear. Therefore, we compared the anthropometric measurements and prevalence of metabolic abnormalities among 32 FPLD3 subjects (4 M, 28 F; mean ± SD age, 41 ± 17.2 y; body mass index (BMI), 26 ± 4.0 kg/m2) with 271 FPLD2 subjects (66 M, 205 F; age, 37.4 ± 17.0 y; BMI, 26 ± 5.0 kg/m2) from two referral centers in the United States. As compared to those with FPLD2, FPLD3 subjects had borderline higher prevalence of hypertriglyceridemia (66% vs 84%; P = 0.063), but significantly higher prevalence of diabetes (44% vs 72%; P = 0.004), past history of acute pancreatitis (13% vs 52%; P

Background Marked elevations of plasma lipoprotein X (Lp-X) levels have been reported in patients with cholestasis due to primary biliary cirrhosis, pancreatic cancer, hepatitis C, and quetiapine. We now report a patient with extreme elevation of plasma Lp-X due to alcohol-induced cholestasis. Case Presentation A 44 year-old African American male presented with painless jaundice and fatigue for one week. He denied nausea, vomiting, diarrhea, change in stool or urine color, or weight loss. He consumes 720-1080 mL of beer (2-3 cans) every night and admitted to heavier alcohol consumption in the past. On physical examination he had scleral icterus and hepatomegaly but no xanthomas or xanthelasmas. His serum total cholesterol was 1,126 mg/dL (normal range, 120-199 mg/dL), triglycerides were 238 mg/dL (50-150 mg/dL), calculated LDL-cholesterol was 1,072 mg/dL (39 mg/dL). His serum AST, 162 IU/L (10-50 IU/L); ALT, 79 IU/L (10-50 IU/L); alkaline phosphatase, 1,058 IU/L (40-129 IU/L); total bilirubin, 18.8 mg/dL (0.2-1.3 mg/dL); direct bilirubin, 13.5 mg/dL (0-0.3 mg/dL); and gamma glutamyl transferase, 4,583 IU/L (8-61 IU/L) were markedly elevated. His blood alcohol level was 34 mg/dL (not detected), sodium 124 mmol/L (135-145 mmol/L), and platelet count was 84,000/µL (150,000-459,000/µL). His TSH 2.89 µIU/mL (0.4-4.5 µIU/mL), UA without proteinuria, HBV immunized, HCV negative, and anti-mitochondrial antibody negative. CT abdomen revealed hepatic steatosis and gallbladder swelling without evidence of obstruction. MRCP showed cirrhosis without primary sclerosing cholangitis. Serum lipoprotein electrophoresis confirmed the presence of Lp-X. On day 3 of hospitalization, his cholestasis improved and his serum total bilirubin 10.0 mg/dL, direct bilirubin 7.4 mg/dL, AST 108 IU/L, ALT 66 IU/L, and alkaline phosphatase 663 IU/L had improved. The patient was advised to abstain from all alcohol consumption. Telephone follow up 2 months later with his wife revealed that he had stopped drinking alcohol and that his jaundice had resolved. Conclusions Although alcohol-induced cholestasis is a well-recognized entity, such presentation with extreme elevations of Lp-X has not been previously reported. In such patients, it is important to establish whether extreme hypercholesterolemia is due to LDL or Lp-X since, as opposed to LDL, Lp-X elevations are not considered to be atherogenic.

Background: FPLD2, a rare autosomal dominant disorder due to heterozygous missense mutations in LMNA, is characterized by gradual loss of subcutaneous (sc) fat from the limbs starting during late childhood and predisposition to metabolic complications, such as diabetes, dyslipidemia and hepatic steatosis. Some patients, especially females, accumulate excess sc fat in the chin, neck, supraclavicular and perineal regions. We report disfiguring and disabling lipomatoses in unusual locations with thiazolidinedione therapy in two women with FPLD2. Clinical Cases: A 57-year-old white female with FPLD2, due to heterozygous p.R482Q LMNA mutation, developed recurrent large lipomatoses in the axillae at age 33 years, and later in the posterior neck (buffalo hump), mons pubis and above sacrum. She developed diabetes at age 30 and was started on pioglitazone 45 mg daily, which was switched to rosiglitazone 8 mg daily at age 43 years. Supra-sacral lipomatoses were approximately 40 cm X 20 cm bilaterally and continued to grow despite lipectomy and multiple liposuctions. Rosiglitazone was stopped at age 56 years, and she reported no further increase in the size of lipomatoses. Her other medications included colesevelam, atorvastatin, metformin, glimepiride, lisinopril, losartan, hydrochlorothiazide, aspirin, insulin and dulaglutide. Her 54-year-old younger sister with FPLD2 (heterozygous p.R482Q LMNA mutation) was treated with lisinopril, metoprolol, atorvastatin, liraglutide, and insulin glargine and aspart, but no history of taking thiazolidinediones, and she never developed any lipomatoses. Another 43-year-old white female with FPLD2, due to heterozygous p.S583L LMNA mutation, was noticed to have lipomatous deposits in the axillae, medial gluteal region, labia and perineal regions. She developed diabetes mellitus at age 36 years and took metformin for 6 years and pioglitazone 30 mg daily for one year before she noticed the lipomatoses. Her other medications included atorvastatin, aldactone and vitamin D3. Pioglitazone was stopped and after one year, she reported reduction in the size of lipomatoses. Conclusion: Thiazolidinediones are selective peroxisomal proliferator-activated receptor-γ agonists and induce weight gain by increasing fat mass, especially subcutaneous depots. Our cases suggest that thiazolidinediones can cause undesired growth of non-lipodystrophic adipose tissue in patients with FPLD2 and thus should be avoided.

Familial partial lipodystrophy (FPLD) is a rare, mostly autosomal dominant disorder characterized by selective loss of subcutaneous fat from the extremities. Patients with FPLD are predisposed to insulin resistance, dyslipidemia, diabetes mellitus, cardiac abnormalities (coronary heart disease [CHD], cardiomyopathy and conduction system disorders) and hepatic steatosis. FPLD2 (the Dunnigan variety) is the most common subtype which is caused by heterozygous variants in the lamin A/C (LMNA) gene. Over 50 LMNA causal variants have been reported in patients with FPLD2, with p.R482W and p.R482Q comprising ~75% of the families. We report 5 novel LMNA variants (c.722T>C, p.L241P; c.848A>G, p.N283S; c.1396A>G, p.N466D; c.1543A>G, p.K515E; c.1744C>A, p.R582S) in 5 families, where a female proband presented to us with moderately-severe FPLD, from among a total cohort of 264 FPLD2 families, with 259 families harboring other known pathogenic LMNA variants. The p.L241P variant was found in a 62-year-old female with a body mass index (BMI) of 28 kg/m2. She had hypertriglyceridemia. She is adopted and has two offsprings, who have not yet been examined and genotyped. The p.N283S variant was found in two males and two females from the same family (Age 40–74 y; BMI 18–45 kg/m2). Of these, only the 74-year-old female proband had clinical lipodystrophy, diabetes and hypertriglyceridemia. The other three subjects did not have lipodystrophy. Thus, this variant did not segregate with the phenotype of lipodystrophy in this family likely due to low penetrance or reduced clinical expressivity. The p.N466D variant was found in a 53-year-old female (BMI 26 kg/m2) who had diabetes and hypertriglyceridemia. The p.K515E variant was found in 4 females and 1 male who belonged to the same family (Age 29–62 y; BMI 19–26 kg/m2). All of them had lipodystrophy and hypertriglyceridemia and three of them had diabetes. The p.R582S variant was found in 3 males and one female who belonged to the same family (Age 19–76 y; BMI 16–30 kg/m2). All of them had lipodystrophy but only two of them had diabetes and hypertriglyceridemia. Eight of them had hypertension, three had CHD, one of them had acute pancreatitis and another one had a stroke. None of these patients had cardiomyopathy, cardiac conduction system defects or myopathy. In conclusion, we report genotype-phenotype relationship of 5 novel LMNA variants in patients presenting with FPLD2, with variable prevalence of diabetes, hypertriglyceridemia hypertension and CAD. None of these variants are associated with cardiomyopathy or myopathy or progeroid features. Our report adds to the allelic and clinical heterogeneity associated with LMNA variants.

Background: Molecular basis of diet responsive hypercholesterolemia remains unclear. We report diet-responsive severe hypercholesterolemia in a young female with cardiofaciocutaneous syndrome type 3 (CFC3) due to a heterozygous pathogenic MAP2K1 variant, suggesting a role of common MAPK variants in LDL-cholesterol (LDL-C) response to diet. Clinical case: A 3-year-old Caucasian female with CFC3 (macrocephaly, frontal bossing, wide nasal root with depressed bridge, anteverted nares, low set fleshy ears, congenital pulmonic valve stenosis, postnatal growth deficiency, hypotonia, and neurocognitive impairment) due to a de novo heterozygous c.389A>G, p.Tyr130Cys pathogenic variant in MAP2K1, presented with extremely elevated serum total cholesterol of 446 mg/dL, triglycerides of 239 mg/dL, HDL-cholesterol of 53 mg/dL, LDL-C of 335 mg/dL (normal range < 110 mg/dL) and serum apolipoprotein B level 219 mg/dL (normal range < 90 mg/dL). Her LDL-C was 252 mg/dL a year ago and 215 mg/dL one month prior to presentation. Reducing total dietary fat to 20–25% of total energy and saturated fat to A; p.Asp748Asn, (Minor allele frequency 0.00008) in the patient and her father. Whole exome sequencing of the patient and both parents showed no known disease-causing variants in LDLR, APOB, PCSK9, LDLRAP1, APOE, STAP1, LIPA, ABCG5, ABCG8 and other known hyperlipidemia-related genes. There are no previous reports of hypercholesterolemia in patients with CFC3. MAP2K1 stimulates various MAP kinases upon wide variety of extra- and intracellular signal and is involved in cell proliferation, differentiation, transcription regulation and development. Previous studies of the relationship between p42/44MAPK activation and LDLR expression in human hepatoma HepG2-derived cell line showed that that activation of the Raf-1/MEK/p42/44MAPK cascade induces LDLR expression and modulation of the Raf-1 kinase signal strength can determine LDLR expression levels. Thus, extent of MAPK activation can alter signaling of LDLR, resulting in hypercholesterolemia. Conclusion: Our case report suggests that MAP2K1 may play a significant role in LDLR signaling, and some MAP2K1 variants may be associated with diet-responsive hypercholesterolemia. Larger studies are required to assess dietary response to LDL-C in subjects with MAP2K1 variants.

Defects in the biosynthesis of phospholipids and neutral lipids are associated with cell membrane dysfunction, disrupted energy metabolism, and diseases including lipodystrophy. In these pathways, the 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT) enzymes transfer a fatty acid to the sn-2 carbon of sn-1-acylglycerol-3-phosphate (lysophosphatidic acid) to form sn-1, 2-acylglycerol-3-phosphate [phosphatidic acid (PA)]. PA is a precursor for key phospholipids and diacylglycerol. AGPAT1 and AGPAT2 are highly homologous isoenzymes that are both expressed in adipocytes. Genetic defects in AGPAT2 cause congenital generalized lipodystrophy, indicating that AGPAT1 cannot compensate for loss of AGPAT2 in adipocytes. To further explore the physiology of AGPAT1, we characterized a loss-of-function mouse model (Agpat1-/-). The majority of Agpat1-/- mice died before weaning and had low body weight and low plasma glucose levels, independent of plasma insulin and glucagon levels, with reduced percentage of body fat but not generalized lipodystrophy. These mice also had decreased hepatic messenger RNA expression of Igf-1 and Foxo1, suggesting a decrease in gluconeogenesis. In male mice, sperm development was impaired, with a late meiotic arrest near the onset of round spermatid production, and gonadotropins were elevated. Female mice showed oligoanovulation yet retained responsiveness to gonadotropins. Agpat1-/- mice also demonstrated abnormal hippocampal neuron development and developed audiogenic seizures. In summary, Agpat1-/- mice developed widespread disturbances of metabolism, sperm development, and neurologic function resulting from disrupted phospholipid homeostasis. AGPAT1 appears to serve important functions in the physiology of multiple organ systems. The Agpat1-deficient mouse provides an important model in which to study the contribution of phospholipid and triacylglycerol synthesis to physiology and diseases.

A several fold increase in triacylglycerol is observed in the livers of lipodystrophic Agpat2−/− mice. We have previously reported an unexpected increase in the phosphatidic acid (PA) levels in the livers of these mice and that a few specific molecular species of PA were able to transcriptionally upregulate hepatic gluconeogenesis. In the current study, we measured the metabolites and expression of associated enzymes of the sphingolipid synthesis pathway. The entire sphingolipid pathway was activated both at the gene expression and the metabolite level. The levels of some ceramides were increased by as much as ~eightfold in the livers of Agpat2−/− mice. Furthermore, several molecular species of ceramides were increased in the plasma of Agpat2−/− mice, specifically ceramide C16:0, which was threefold elevated in the plasma of both the sexes. However, the ceramides failed to increase glucose production in mouse primary hepatocytes obtained from wild-type and Agpat2−/− mice, further establishing the specificity of PA in the induction of hepatic gluconeogenesis. This study shows elevated levels of sphingolipids in the steatotic livers of Agpat2−/− mice and increased expression of associated enzymes for the sphingolipid pathway. Therefore, this study and those in the literature suggest that ceramide C16:0 could be used as a biomarker for insulin resistance/type 2 diabetes mellitus., Sphingolipids and gene expression of the sphingolipid synthesis pathway are upregulated in the livers of lipodystrophic Agpat2−/− mice but do not enhance gluconeogenesis in mouse primary hepatocytes.

BackgroundA protein that is expressed on capillary endothelial cells, called GPIHBP1 (glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1), binds lipoprotein lipase and shuttles it to its site of action in the capillary lumen. A deficiency in GPIHBP1 prevents lipoprotein lipase from reaching the capillary lumen. Patients with GPIHBP1 deficiency have low plasma levels of lipoprotein lipase, impaired intravascular hydrolysis of triglycerides, and severe hypertriglyceridemia (chylomicronemia). During the characterization of a monoclonal antibody-based immunoassay for GPIHBP1, we encountered two plasma samples (both from patients with chylomicronemia) that contained an interfering substance that made it impossible to measure GPIHBP1. That finding raised the possibility that those samples might contain GPIHBP1 autoantibodies.MethodsUsing a combination of immunoassays, Western blot analyses, and immunocytochemical studies, we tested the two plasma samples (as well as samples from other patients with chylomicronemia) for the presence of GPIHBP1 autoantibodies. We also tested the ability of GPIHBP1 autoantibodies to block the binding of lipoprotein lipase to GPIHBP1.ResultsWe identified GPIHBP1 autoantibodies in six patients with chylomicronemia and found that these autoantibodies blocked the binding of lipoprotein lipase to GPIHBP1. As in patients with GPIHBP1 deficiency, those with GPIHBP1 autoantibodies had low plasma levels of lipoprotein lipase. Three of the six patients had systemic lupus erythematosus. One of these patients who had GPIHBP1 autoantibodies delivered a baby with plasma containing maternal GPIHBP1 autoantibodies; the infant had severe but transient chylomicronemia. Two of the patients with chylomicronemia and GPIHBP1 autoantibodies had a response to treatment with immunosuppressive agents.ConclusionsIn six patients with chylomicronemia, GPIHBP1 autoantibodies blocked the ability of GPIHBP1 to bind and transport lipoprotein lipase, thereby interfering with lipoprotein lipase-mediated processing of triglyceride-rich lipoproteins and causing severe hypertriglyceridemia. (Funded by the National Heart, Lung, and Blood Institute and the Leducq Foundation.).

Despite considerable progress in identifying causal genes for lipodystrophy syndromes, the molecular basis of some peculiar adipose tissue disorders remains obscure. In an Israeli-Arab pedigree with a novel autosomal recessive, multiple symmetric lipomatosis (MSL), partial lipodystrophy and myopathy, we conducted exome sequencing of two affected siblings to identify the disease-causing mutation. The 41-year-old female proband and her 36-year-old brother reported marked accumulation of subcutaneous fat in the face, neck, axillae, and trunk but loss of subcutaneous fat from the lower extremities and progressive distal symmetric myopathy during adulthood. They had increased serum creatine kinase levels, hypertriglyceridemia and low levels of high-density lipoprotein cholesterol. Exome sequencing identified a novel homozygous NC_000019.9:g.42906092C>A variant on chromosome 19, leading to a NM_005357.3:c.3103G>T nucleotide change in coding DNA and corresponding p.(Glu1035*) protein change in hormone sensitive lipase (LIPE) gene as the disease-causing variant. Sanger sequencing further confirmed the segregation of the mutation in the family. Hormone sensitive lipase is the predominant regulator of lipolysis from adipocytes, releasing free fatty acids from stored triglycerides. The homozygous null LIPE mutation could result in marked inhibition of lipolysis from some adipose tissue depots and thus may induce an extremely rare phenotype of MSL and partial lipodystrophy in adulthood associated with complications of insulin resistance, such as diabetes, hypertriglyceridemia and hepatic steatosis. © 2016 Wiley Periodicals, Inc.

BackgroundFamilial hypercholesterolemia (FH) confers a very high risk of premature cardiovascular disease and is commonly caused by mutations in low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin/kexin type 9 (PCSK9) and very rarely in LDLR adaptor protein 1 (LDLRAP1) genes.ObjectiveTo determine the prevalence of pathogenic mutations in the LDLR, APOB, and PCSK9 in a cohort of subjects who met Simon Broome criteria for FH and compare the clinical characteristics of mutation-positive and mutation-negative subjects.MethodsNinety-three men and 107 women aged 19 to 80 years from lipid clinics in the United States and Canada participated. Demographic and historical data were collected, physical examination performed, and serum lipids/lipoproteins analyzed. Targeted sequencing analyses of LDLR and PCSK9 coding regions and exon 26 of APOB were performed followed by detection of LDLR deletions and duplications.ResultsDisease-causing LDLR and APOB variants were identified in 114 and 6 subjects, respectively. Of the 58 LDLR variants, 8 were novel mutations. Compared with mutation-positive subjects, mutation-negative subjects were older (mean 49 years vs 57 years, respectively) and had a higher proportion of African Americans (1% vs 12.5%), higher prevalence of hypertension (21% vs 46%), and higher serum triglycerides (median 86 mg/dL vs 122 mg/dL) levels.ConclusionsLDLR mutations were the most common cause of heterozygous FH in this North American cohort. A strikingly high proportion of FH subjects (40%) lacked mutations in known culprit genes. Identification of underlying genetic and environmental factors in mutation-negative patients is important to further our understanding of the metabolic basis of FH and other forms of severe hypercholesterolemia.

BACKGROUND: Despite major advances in understanding the molecular basis of various genetic lipodystrophy syndromes, some rare patients still remain unexplained. CASES: We report a novel autosomal recessive lipodystrophy affecting two sisters aged 17 and 19 years and characterised by early onset intellectual disability, and subsequent development of near-generalised loss of subcutaneous fat with diabetes mellitus, extreme hypertriglyceridemia, hepatic steatosis, short stature, clinodactyly, joint contractures, leiomyoma of uterus and cataracts in childhood. The lipodystrophy was more pronounced in the upper and lower extremities, and there was no associated muscular hypertrophy. Using whole exome sequencing in this consanguineous Hispanic pedigree, we report disease-causing homozygous p.Arg545His LMNA variant in the affected subjects, and confirm the lack of pathogenic variants in other known lipodystrophy genes. The mother and a younger brother were both heterozygous for p.Arg545His LMNA variant and were overweight with acanthosis nigricans without any evidence of lipodystrophy. Our patients are distinct from previously reported autosomal recessive lipodystrophy syndromes and have no overlap with other autosomal recessive laminopathies, including mandibuloacral dysplasia, Emery-Dreifuss muscular dystrophy and Charcot-Marie-Tooth neuropathy. CONCLUSION: Our report of this unusual familial generalised lipodystrophy syndrome adds to the pleiotropy associated with biallelic autosomal recessive LMNA variants.

Background: Homozygous mutations in lamin A/C (LMNA) gene are extremely rare and have been reported to cause mandibuloacral dysplasia type A, Emery-Dreifuss muscular dystrophy-3, Charcot-Marie-Tooth axonal neuropathy type2B1, progeroid syndrome and severe familial partial lipodystrophy. We report a novel syndrome of familial generalized lipodystrophy due to homozygous p.Arg545His LMNA mutation in two sisters. Clinical Cases: The proband, a 18.5-year-old Hispanic female, was diagnosed with speech delay at age 4 years; and developed lipodystrophy and acanthosis nigricans at age 10. She was diagnosed with diabetes and elevated serum aspartate and alanine aminotransferases at 11 years of age; and extreme hypertriglyceridemia (serum triglycerides >10,000 mg/dL), xanthomas and three episodes of acute pancreatitis at 14 years of age. Her liver biopsy showed hepatocytes with pleomorphic and enlarged mitochondria and variably enlarged glycogenated nuclei, with macro-vesicular and micro-vesicular steatosis in 2% of hepatocytes. At age 16, she had severe metabolic abnormalities despite low fat diet, metformin 1000 mg, insulin > 600 units, fish oil 4 g, gemfibrozil 600 mg, and lisinopril 10 mg per day. Subcutaneous metreleptin 2.5 mg/d was initiated which improved glycemic control, liver enzymes and triglycerides, with no further episode of acute pancreatitis. She currently takes metreleptin and insulin 140 units daily. She recently developed right hydrosalpinx, 1.8 cm posterior uterine fibroids, and 2.1 cm endometriosis. Her 17-year-old sister had speech delay in infancy, and recurrent pyelonephritis, and lost sc fat in early childhood. She developed hypothyroidism, elevated transaminases, and diabetes at age 10, 14, and 16 years, respectively. She had one episode of acute pancreatitis and an incidental 6.8 cm ovarian cyst was found at age 16 years. Both of them have generalized loss of sc fat, more from the extremities than from the trunk, thin lips with perioral pigmentation, dry skin, short 5th finger with clindodactyly, and bilateral ankle contractures. The proband also had bilateral knee contractures. They have no acro-osteolysis, buffalo hump, double chin, myopathy or neuropathy. Whole exome sequencing of both the patients revealed homozygous mutation chr1:156107470G>A, p.Arg545His (rs142191737, minor allele frequency 0.000038 in Latinos) in LMNA (http://gnomad.broadinstitute.org). The mother and a younger brother are both heterozygous for p.Arg545His variant and are healthy without any lipodystrophy. Conclusions: Homozygous p.Arg545His LMNA mutation results in a novel syndrome of childhood-onset familial generalized lipodystrophy with early onset diabetes, hypertriglyceridemia, and hepatic steatosis, speech delay and joint contractures. Metreleptin therapy may be helpful in improving metabolic derangements.