Novel peroxisome proliferator-activated receptor gamma mutation in a family with familial partial lipodystrophy type 3

2015 ◽  
Vol 84 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Konstanze Miehle ◽  
Joseph Porrmann ◽  
Diana Mitter ◽  
Michael Stumvoll ◽  
Christiane Glaser ◽  
...  
2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A307-A308
Author(s):  
Kajal Shah ◽  
Marina Charitou

Abstract Familial partial lipodystrophy (FPL) is a rare group of autosomal dominant genetic disorders which causes variable loss of subcutaneous fat from abdomen, thorax or extremities in addition to the numerous metabolic complications like insulin resistance, diabetes mellitus and dyslipidemia1. FPL type 3 was first characterized by Agarwal et al. in 20021, in which peroxisome proliferator-activated receptor-γ (PPARγ) gene was the molecular basis of this disorder. It is extremely rare and so far only 30 patients or so have been recognized with this mutation2. FPL3 is unique because it generally spares the loss of fat from trunk, face and neck region and also presents with more severe metabolic derangements. We report a case of a young female with PPARγ mutation leading to numerous metabolic complications. A 19 year old female with FPL3 was seen by adult endocrinology as a transition from pediatric endocrinology. She was found to have hypertriglyceridemia on routine labs done at the age of 11. Patient reported loss of subcutaneous fat from her extremities and eruptive xanthoma on flexor surfaces at the time of diagnosis along with a positive family history of hypertriglyceridemia induced pancreatitis and Myocardial infarction at the age of 40 in her father. Her triglyceride level has varied between 600 and 3000 (normal 20–149 mg/dl) over the years. FPL3 was diagnosed based on genetic testing. She was prescribed fenofibrate and fish oil, and statin was added thereafter. She developed type 2 diabetes and was started on metformin and pioglitazone. She was noted to have hypertension and was treated with amlodipine and lisinopril. She also was found to have Polycystic Ovarian Syndrome (PCOS) based on menstrual irregularities, hirsutism and ultrasound showing multiple ovarian cysts, and was treated with spironolactone. Her most recent labs show triglyceride level of 2400 mg/dl and HbA1c of 8.3. PPARγ gene mutation in FPL3 leads to insulin resistance and hence patients often develop hypertriglyceridemia, type 2 diabetes, PCOS and hypertension. In terms of treatment options, we are still limited to pioglitazone, metformin, statins and fish oil. Often these are not sufficient in addressing the complexity of metabolic derangements in these patients who have an increased risk of cardiovascular events at a young age. Further research about agents targeting this gene in particular would be beneficial. 1. Agarwal et al. A novel heterozygous mutation in peroxisome proliferator-activated receptor-gamma gene in a patient with familial partial lipodystrophy. J Clin Endocrinol Metab. 2002 Jan; 87(1):408–411. 2. Garg A. Lipodystrophies: Genetic and Acquired Body Fat Disorders. J Clin Endocrinol Metab. 2011;96(11): 3313–3325.


2007 ◽  
Vol 21 (5) ◽  
pp. 1049-1065 ◽  
Author(s):  
Ellen H. Jeninga ◽  
Olivier van Beekum ◽  
Aalt D. J. van Dijk ◽  
Nicole Hamers ◽  
Brenda I. Hendriks-Stegeman ◽  
...  

Abstract The nuclear receptor peroxisome proliferator-activated receptor (PPAR) γ plays a key role in the regulation of glucose and lipid metabolism in adipocytes by regulating their differentiation, maintenance, and function. A heterozygous mutation in the PPARG gene, which changes an arginine residue at position 425 into a cysteine (R425C), has been reported in a patient with familial partial lipodystrophy subtype 3 (FPLD3). The strong conservation of arginine 425 among nuclear receptors that heterodimerize with retinoic acid X receptor prompted us to investigate the functional consequences of the R425C mutation on PPARγ function. Here we show that this mutant displayed strongly reduced transcriptional activity compared with wild-type PPARγ, irrespective of cell type, promoter context, or ligand, whereas transrepression of nuclear factor-κB activity remained largely intact. Our data indicate that the reduced transcriptional activity of PPARγ R425C is not caused by impaired corepressor release, but due to reduced dimerization with retinoic acid X receptor α in combination with reduced ligand binding and subsequent coactivator binding. As a consequence of these molecular defects, the R425C mutant was less effective in inducing adipocyte differentiation. PPARγ R425C did not inhibit its wild-type counterpart in a dominant-negative manner, suggesting a haploinsufficiency mechanism in at least some FPLD3 patients. Using molecular dynamics simulations, substitution of R425 with cysteine is predicted to cause the formation of an alternative salt bridge. This structural change provides a likely explanation of how mutation of a single conserved residue in a patient with FPLD3 can disrupt the function of the adipogenic transcription factor PPARγ on multiple levels.


Diabetes ◽  
2021 ◽  
Vol 70 (Supplement 1) ◽  
pp. 198-LB
Author(s):  
PATRÍCIA V. WANDERLEY ◽  
JOAO C. DIAS ◽  
MARTA W. VIEIRA ◽  
GIANE GARCIA ◽  
ITUO T. FILHO ◽  
...  

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