Case report: two novel PPARG pathogenic variants associated with type 3 familial partial lipodystrophy in Brazil.

INTRODUCTION AND AIM: Type 3 Familial Partial Lipodystrophy (FPLD3) is a rare metabolic disease related to pathogenic PPARG gene variants. FPLD3 is characterized by a loss of fatty tissue in the upper and lower limbs, hips, and face. FPLD3 pathophysiology is usually associated with metabolic comorbidities such as type 2 diabetes, insulin resistance, hypertriglyceridemia, and liver dysfunction. Here, we clinically and molecularly characterized FPLD3 patients harboring novel PPARG pathogenic variants. MATERIALS AND METHODS: Lipodystrophy-suspected patients were recruited by clinicians from an Endocrinology Reference Center. Clinical evaluation was performed, biological samples were collected for biochemical analysis, and DNA sequencing was performed to define the pathogenic variants associated with the lipodystrophic phenotype found in our clinically diagnosed FPLD subjects. Bioinformatics predictions were conducted to characterize the novel mutated PPARγ proteins. RESULTS: We clinically described FPLD patients harboring two novel heterozygous PPARG variants in Brazil. Case 1 had the c.533T > C variant, which promotes the substitution of leucine to proline in position 178 (p.Leu178Pro), and cases 2 and 3 had the c.641 C > T variant, which results in the substitution of proline to leucine in the position 214 (p.Pro214Leu) at the PPARγ2 protein. These variants result in substantial conformational changes in the PPARγ2 protein. CONCLUSION: Two novel PPARG pathogenic variants related to FPLD3 were identified in a Brazilian FPLD cohort. These data will provide new epidemiologic data concerning FPLD3 and help understand the genotype-phenotype relationships related to the PPARG gene.

High prevalence of Berardinelli-Seip Congenital Lipodystrophy in Rio Grande do Norte State, Northeast Brazil.

BACKGROUND: Berardinelli-Seip Congenital Lipodystrophy (BSCL) is a rare disease characterized by the almost complete absence of adipose tissue. Although a large number of BSCL cases was previously identified in Rio Grande do Norte (RN), a state in Northeast Brazil, its prevalence in RN regions and municipalities remains unknown. The purpose of this study was to better characterize the prevalence of BSCL in RN. METHODS: A descriptive study was conducted using secondary data obtained from the Association of Parents and People with BSCL of RN to determine its prevalence. The patients' socio-demographic characteristics and geolocalization were analyzed. RESULTS: We estimated a total of 103 BSCL cases in RN, resulting in a prevalence of 3.23 per 100,000 people. The Central Potiguar mesoregion, Seridó territory, Carnaúba dos Dantas and Timbaúba dos Batistas municipalities had a much higher prevalence of BSCL, with 20.56, 20.66, 498.05 and 217.85 per 100,000 people, respectively. CONCLUSIONS: Together, our results showed that BSCL is highly prevalent in RN and confirmed that our state has one of the highest prevalences of this lipodystrophy worldwide. More studies are still needed to better estimate the prevalence and incidence of BSCL in RN as well as in other states in Brazil. Trial registration Study Number 31809314.0.0000.5568.

Is nonalcoholic fatty liver disease an endogenous alcoholic fatty liver disease? - A mechanistic hypothesis.

Nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD) are so similar that only a detailed history of alcohol intake can distinguish one from the other. Because subjects with NAFLD produce significantly more endogenous ethanol (EE) than controls, some researchers suspected that these similarities are not merely coincidental. For this reason, it was attempted to show that NAFLD is actually an endogenous alcoholic fatty liver disease (EAFLD). However, negligible blood-alcohol concentration (BAC) and the inability of gut microbiota to produce hepatotoxic concentrations of EE rejected this hypothesis. To clarify these conflicting results, we provide a mechanistic framework explaining how NAFLD may be an EAFLD. First of all, the key finding is that ethanol is a prodrug, enabling the idea that AFLD may develop with negligible/absent BAC. Second, extrahepatic acetaldehyde (ACD) alone recapitulates AFLD and is about 330-fold more hepatotoxic than that generated inside the liver. Third, gut microbiota can even produce much larger amounts of EE than those currently considered cirrhotogenic for man. Fourth, an extensive gut-liver axis first-pass metabolism of ethanol prevents the development of significant BAC in NAFLD. Fifth, all genes involved in EE metabolism are upregulated in the livers of patients with nonalcoholic steatohepatitis (NASH). Last, overexpression of the gene encoding alcohol dehydrogenase (ADH) 4 implicates liver exposure to high concentrations of EE. In conclusion, this work provides mechanistic explanation supporting the assumption that NAFLD may indeed be an EAFLD. If validated by further testing, the hypothesis may help develop novel therapeutic and preventive strategies against this ubiquitous condition.