Gene expression profile in hereditary transthyretin amyloidosis: differences in targeted and source organs

INTRODUCTION: Hereditary transthyretin amyloidosis (ATTR) is a genetic disease caused by a point mutation in the TTR gene that causes the liver to produce an unstable TTR protein. The most effective treatment has been liver transplantation in order to replace the variant TTR producing liver with one that produces only wild-type TTR. ATTR amyloidosis patients’ livers are reused for liver sick patients, i.e. the Domino procedure. However, recent findings have demonstrated that ATTR amyloidosis can develop in the recipients within 7–8 years. The aim of this study was to elucidate how the genetic profile of the liver is affected by the disease, and how amyloid deposits affect target tissue. METHODS: Gene expression analysis was used to unravel the genetic profiles of Swedish ATTR V30M patients and controls. Biopsies from adipose tissue and liver were examined. RESULTS AND CONCLUSIONS: ATTR amyloid patients’ gene expression profile of the main source organ, the liver, differed markedly from that of the controls, whereas the target organs’ gene expression profiles were not markedly altered in the ATTR amyloid patients compared to those of the controls. An impaired ER/protein folding pathway might suggest ER overload due to mutated TTR protein.