ENDOSCOPIC AND PATHOLOGICAL MANIFESTATIONS OF THE GASTROINTESTINAL-TRACT IN FAMILIAL AMYLOIDOTIC POLYNEUROPATHY TYPE-I (MET30)

Objectives. To evaluate the characteristic changes in the gastrointest inal tract in familial amyloidotic polyneuropathy (FAP) (Met30), both fibre gastroscopy and colonoscopy studies were performed in FAP (Met30 ) patients. Microscopic changes were also examined in autopsied and bi opsied materials from patients with FAP, and compared with data from a utopsied samples from patients with AL amyloidosis, and secondary amyl oidosis patients. Design. Endoscopic and histopathological study. Sett ing. Kumamoto University Hospital, Kumamoto, Japan. Subjects. Nine pat ients with FAP (Met30) underwent fibre gastroscopy and colonoscopy. Si x autopsied and 23 biopsied gastrointestinal samples from FAP patients , four from autopsied amyloidosis (including two myeloma associated fo rm), and two from autopsied secondary amyloidosis patients were examin ed for histopathological study. Main outcome measures. Fibre gastrosco py and colonoscopy were employed for macroscopic study. Congo red and H-E staining were performed for histopathological study. Macroscopic c hanges in the gastrointestinal tract and microscopic differences in th e amyloid distribution pattern were compared between the different typ es of amyloidosis. Results. Fibre gastroscopy and colonoscopy for nine FAP patients revealed that four showed a fine granular appearance in the duodenum, three showed lack of lustre, and two showed mucosal fria bility in the gastrointestinal tract; however, no macroscopic abnormal ity was observed in four other FAP patients. Histopathological examina tion of tissue from FAP patients revealed that, although a small amoun t of amyloid was recognized in the submucosa perivascular layer, a sig nificant amount of amyloid was seen in and around the nerves of the ga strointestinal tract, but very little in Auerbach's nerve plexus. In t otal, the amount of deposited amyloid in the tissues was small compare d with that in other types of systemic amyloidosis, such as AL and sec ondary amyloidosis. Conclusion. These results suggest that the major r eason why FAP patients show such severe gastrointestinal symptoms, com pared with other types of systemic amyloidosis, may be because of the deposition of a significant amount of amyloid in the nerves in the gas trointestinal tract.