Familial hypobetalipoproteinemia: clinical characterization of a new mutation in the APOB gene

BACKGROUND AND OBJETIVE: Familial hypobetalipoproteinemia (FHB) is usually due to mutations in the APOB gene. Almost 60 different mutations have been reported. We report a Spanish family with FHB phenotype and a new mutation. PATIENT AND METHODS: We performed an analytical, localizing and molecular study of the APOB gene in the proband and in two relatives phenotypically affected. RESULTS: The proband was a 32-year-old woman with moderate to severe mental retardation, morbid obesity, hypocholesterolemia, hypertransaminasemia, and hepatic steatosis. The familial phenotypic study was positive in other 6 relatives. The genetic study confirmed the presence of a novel mutation (apoB-69.27) in the APOB gene. The proband, her mother and one maternal great aunt were heterozygote for that mutation. CONCLUSIONS: FHB has a variable phenotypic expression that can range from oligosymptomatic disease to severe neurological damage.