Current and Emerging Issues in Familial Hypobetalipoproteinemia-related Steatotic Liver Diseases.

Familial hypobetalipoproteinemia (FHBL), caused by apolipoprotein B (APOB) variants, disrupts APOB-containing lipoprotein synthesis, leading to reduced serum total cholesterol, low-density lipoprotein cholesterol, and APOB. Heterozygous carriers are often asymptomatic, while homozygotes exhibit severe manifestations like malabsorption, vitamin deficiencies, and hepatic steatosis. In recent years, FHBL has attracted increasing attention due to its association with liver disease and its role as a unique monogenic model of steatotic liver disease independent of cardiometabolic risk factors. Mechanistically, lipid overload, endoplasmic reticulum stress, oxidative damage, and impaired autophagy may drive hepatocellular injury and fibrosis. Challenges include insufficient diagnosis, sparse epidemiological data, and unclear disease progression. Enhanced genetic testing, mechanistic research, and longitudinal studies are critical to improving diagnosis, risk assessment, and therapies for FHBL-associated liver disease.