Study of PNPLA3 Genetic Polymorphisms in Patients With Non-Alcoholic Fatty Liver Disease in an Ultramarine Population (AdipoDROMExpo)

Metabolic dysfunction associated liver disease (MASLD) is a significant public health concern worldwide with a complex etiology attributed to behavioural, environmental, and genetic causes. The worldwide prevalence of MASLD is estimated to be 32.4% and constantly rising.

Several studies suggest differences in the prevalence and severity of MASLD by race or ethnicity, which may be linked to differences in lifestyle, diet, metabolic comorbidity profile, and genetic background, among others.

Race/ethnicity research is essential as it can provide valuable information regarding biological and genetic differences among people with similar cultural, dietary, and geographical backgrounds.

There is ample epidemiological evidence on the role of genetic susceptibility in MASLD, mainly from studies showing the clustering of MASLD cases among families and observing differences in the prevalence and severity of MASLD among ethnicities.

The Overseas territories population is predominantly of African descent due to slave trade of population from sub-Saharan Africa between the seventeenth and nineteenth centuries. They have also been a mixture from Europeans and Indians. Indian are descents from Latin America, initially present on the territories, and from Asia, after the abolition of slavery. Data about MASLD in Overseas territories are scarce. To our knowledge, one study reported the prevalence of MASLD in Caribbean and Hispanic populations resident in the United States compared with Hispanic residents in Latin America (Kallwitz 2015). In the later study, rates of MASLD were significantly lower in persons with Caribbean origin than those of Latin America heritage.

Genetic susceptibility variations may partially explain the heterogeneity observed in the MASLD prevalence/incidence estimates from different geographical regions and the variability in disease severity among individuals. Genetic factors have been suggested as one of the underlying causes of racial/ethnic differences in susceptibility to MASLD.

Among the building blocks of metabolic syndrome, type 2 diabetes and obesity have been significantly associated with an increased risk of MASH with more severe progression to cirrhosis or liver cancer.

However, in overseas, the prevalence of type 2 diabetes (10%), high blood pressure (28%), or obesity (30%) are among the highest in France.

PNPLA3 expression is implicated in intrahepatic lipid accumulation and is associated with lipotoxicity and the more severe phenotypes, including fibrosis and carcinogenesis. Therefore, in this study, PNPLA3 polymorphisms will be analysed to evaluate the profile of MASLD patients in overseas territories. A biological sample will be taken to analyse PNPLA3 polymorphisms in DROMSteatExpo study.

IInclusion Criteria

-Adult patients (≥18 years old) seen in consultation or hospitalized in the Hepato-Gastroenterology Departments of the University Hospitals of Guadeloupe, French Guiana, and Réunion Island, with a diagnosis of MASLD.

MASLD is defined as evidence of hepatic steatosis associated with overweight/obesity, type 2 diabetes, or metabolic syndrome according to ATP III (2005) criteria.

• Patients affiliated with, or beneficiaries of, a social security scheme.
• Free, informed, and written consent obtained from the participant and signed by both the participant and the investigator (no later than the day of inclusion and prior to any procedure required by the study).

Exclusion criteria

• Patients under 18 years of age.
• Patients unable to provide informed consent; so-called vulnerable populations (individuals under guardianship, judicial protection, etc.).
• Presence of another cause of chronic liver disease, including:

Viral hepatitis (B, C, or E)

Primary biliary cholangitis or primary sclerosing cholangitis

Autoimmune hepatitis

Wilson's disease

Hemochromatosis

Alpha-1 antitrypsin deficiency

Alcoholic liver disease, or daily alcohol consumption >30 g/day for men or >20 g/day for women

-Pregnant women.