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01.12.2014 | Research | Ausgabe 1/2014 Open Access

Orphanet Journal of Rare Diseases 1/2014

THAOS: Gastrointestinal manifestations of transthyretin amyloidosis - common complications of a rare disease

Orphanet Journal of Rare Diseases > Ausgabe 1/2014
Jonas Wixner, Rajiv Mundayat, Onur N Karayal, Intissar Anan, Pontus Karling, Ole B Suhr
Wichtige Hinweise

Electronic supplementary material

The online version of this article (doi:10.​1186/​1750-1172-9-61) contains supplementary material, which is available to authorized users.

Competing interest

Rajiv Mundayat and Onur N. Karayal are employees of and hold stock options in Pfizer Inc. Ole B. Suhr is chairman of the THAOS registry, which is sponsored by Pfizer Inc, and is currently participating in clinical trials sponsored by Pfizer Inc and Alnylam Pharmaceuticals. He has also been a member of expert committees for Pfizer Inc and Alnylam Pharmaceuticals and has served as lecturer at meetings and educational activities sponsored by Pfizer Inc. The remaining authors have no competing interests to declare.

Authors’ contributions

JW contributed to the design of the study and wrote the manuscript. RM contributed to the design of the study, performed the statistical analyses and revised the manuscript. OK contributed to the design of the study and revised the manuscript. IA and PK participated in the planning of the study, in data analysis and in the revision of the manuscript. OBS conceived of the study and participated in its design and coordination. All authors read and approved the final manuscript.



Transthyretin amyloidosis is a systemic disorder caused by amyloid deposits formed by misfolded transthyretin monomers. Two main forms exist: hereditary and wild-type transthyretin amyloidosis, the former associated with transthyretin gene mutations. There are several disease manifestations; however, gastrointestinal complications are common in the hereditary form. The aim of this study was to explore the prevalence and distribution of gastrointestinal manifestations in transthyretin amyloidosis and to evaluate their impact on the patients’ nutritional status and health-related quality of life (HRQoL).


The Transthyretin Amyloidosis Outcomes Survey (THAOS) is the first global, multicenter, longitudinal, observational survey that collects data on patients with transthyretin amyloidosis and the registry is sponsored by Pfizer Inc. This study presents baseline data from patients enrolled in THAOS as of June 2013. The modified body mass index (mBMI), in which BMI is multiplied with serum albumin, was used to assess the nutritional status and the EQ-5D Index was used to assess HRQoL.


Data from 1579 patients with hereditary transthyretin amyloidosis and 160 patients with wild-type transthyretin amyloidosis were analyzed. Sixty-three percent of those with the hereditary form and 15% of those with the wild-type form reported gastrointestinal symptoms at enrollment. Unintentional weight loss and early satiety were the most frequent symptoms, reported by 32% and 26% of those with transthyretin gene mutations, respectively. Early-onset patients (<50 years) reported gastrointestinal complaints more frequently than those with a late onset (p < 0.001) and gastrointestinal symptoms were more common in patients with the V30M mutation than in those with other mutations (p < 0.001). For patients with predominantly cardiac complications, the prevalence of gastrointestinal manifestations was not evidently higher than that expected in the general population. Both upper and lower gastrointestinal symptoms were significant negative predictors of mBMI and the EQ-5D Index Score (p < 0.001 for all).


Gastrointestinal symptoms were common in patients with hereditary transthyretin amyloidosis and had a significant negative impact on their nutritional status and HRQoL. However, patients with wild-type transthyretin amyloidosis or transthyretin mutations associated with predominantly cardiac complications did not show an increased prevalence of gastrointestinal disturbances.
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