Faulty EBF2 Gene Drives Fat Tissue Scarring and Metabolic Collapse in Rare Lipodystrophy

Lipodystrophy syndromes, characterized by selective loss of adipose tissue and consequent severe metabolic dysfunction, remain genetically unexplained in roughly half of partial lipodystrophy (PLD) cases. This study reports the identification of a heterozygous stop-gain variant in EBF2 (chr8:26033143C>A; p.E165X) as a likely cause of atypical PLD in a 23-year-old patient who presented with peripheral fat loss, hepatic steatofibrosis, nephrosclerosis, insulin resistance, dyslipidemia, and hypogonadotropic hypogonadism. Standard lipodystrophy gene panels and initial whole-exome sequencing failed to identify a known causative gene; subsequent whole-genome sequencing and analysis through the Broad Institute Center for Mendelian Genomics pinpointed the EBF2 variant, which was confirmed by Sanger sequencing and shown to be paternally inherited.

EBF2 belongs to the early B cell factor transcription factor family and has established roles in adipocyte differentiation, brown fat thermogenesis, and ECM regulation. The identified truncated protein, EBF2 (1–164), lacks the DNA-binding and dimerization domains essential for full transcriptional activity, raising the hypothesis that it acts as a dominant-negative inhibitor. In vitro studies in 3T3-L1 preadipocytes confirmed that EBF2 knockdown significantly reduced lipid accumulation and suppressed key adipogenic markers including PPARγ and FABP4, and that re-expression of the truncated variant failed to rescue—and in fact worsened—adipogenic defects compared with full-length EBF2.

To model the disease in vivo, the researchers generated heterozygous knockin mice carrying the identical single-nucleotide change (Ebf2E165X/+). During the post-weaning period and especially under high-fat diet (HFD) challenge, these mice showed restricted adipogenesis, defective ECM remodeling with persistent collagen accumulation in fat depots, and abnormal adipocyte hypertrophy—phenocopying the fibrotic adipose histology observed in the patient's subcutaneous biopsies. HFD-fed Ebf2E165X/+ mice also displayed significantly decreased circulating adiponectin and leptin, glucose intolerance, and transcriptomic downregulation of mitochondrial genes involved in fatty acid metabolism and oxidative phosphorylation specifically within adipose tissue.

The epidemiological context further supports pathogenicity: EBF2 has a pLI score of 1.0, indicating extreme intolerance to loss-of-function variation in the general population. Large-scale GWAS data link EBF2 variants to type 2 diabetes, visceral adiposity, hypertension, reduced HDL, and elevated triglycerides—a phenotypic signature that mirrors lipodystrophy-associated metabolic syndrome. Rare variant burden testing in over 344,000 individuals also associated predicted deleterious EBF2 variants with elevated random glucose levels.

Taken together, the study establishes EBF2 as a novel lipodystrophy gene and demonstrates that haploinsufficiency or dominant-negative truncation of EBF2 is sufficient to impair adipose tissue development, ECM homeostasis, and metabolic function. This work expands the genetic diagnostic toolkit for unsolved PLD and implicates ECM remodeling and mitochondrial metabolism as downstream therapeutic targets.