An Isolated Case of Late-onset Amyloidogenic Transthyretin Type Familial Amyloid Polyneuropathy Associated with a Mutant Transthyretin Substituting Methionine for Valine at Position 30 Showing Latent Progressive Cardiac Involvement Confirmed by Serial Annual Electrocardiograms

Late-onset Transthyretin (TTR)-familial Amyloid Polyneuropathy (FAP) with a Long Disease Duration from Non-endemic Areas in Japan

We herein report the case of an 84-year-old woman with transthyretin (TTR) Val30Met-associated familial amyloid polyneuropathy (FAP-ATTR Val30Met), representing a very old case. The patient had muscle weakness and sensory disturbances in her extremities caused by severe peripheral neuropathy. She also had vitreous opacity and orthostatic hypotension, and pyrophosphate scintigraphy showed a myocardial accumulation. Esophagogastroduodenoscopy revealed mucosal amyloid deposits, positive in anti-TTR antibody staining. A TTR gene analysis isolated the Val30Met mutation. More than a few cases of FAP-ATTR develop late, like our own, and their familial histories are often obscure in non-endemic areas, which might make a diagnosis difficult.

Phenotypic expressions of hereditary Transthyretin Ala97Ser related Amyloidosis (ATTR) in Taiwanese

Background

The disease course and early signs specific to ATTR Ala97Ser, the most common endemic mutation in Taiwan, have not been well described. Since new medications can slow down the rate of disease progression, the early diagnosis of this heterogeneous and fatal disease becomes critical.

Methods

We retrospectively reviewed the characteristics of genetically confirmed ATTR Ala97Ser patients at a tertiary referral medical center.

Results

Eight patients from 7 different families were enrolled (61.7 ± 5.5 years). Gastrointestinal symptoms, dyspnea or chest tightness, rather than sensory symptoms, were the initial symptoms in two patients (2/7 = 29%). Body weight loss (3/7 = 43%), muscle wasting (4/7 = 57%), or dysphagia (3/7 = 43%) were the consecutive symptoms. Orthostatic symptoms including orthostatic hypotension (7/7 = 100%), dizziness (6/7 = 86%) and syncope (5/7 = 71%) tended to develop in the late phase of the disease. Autonomic dysfunction was conspicuous. Cardiographic findings included a combination of ventricular wall thickening and pericardial effusion (7/7 = 100%), a granular sparkling appearance of the ventricular myocardium (4/7 = 57%), or conduction abnormalities (5/7 = 71%).

Conclusions

This study broadens the recognition of the initial signs and symptoms, including cardiographic findings and longitudinal manifestations in Taiwanese individuals with ATTR Ala97Ser mutation. These manifestations should prompt doctors to perform further studies and make an early diagnosis.

Electronic supplementary material

The online version of this article (10.1186/s12883-017-0957-4) contains supplementary material, which is available to authorized users.