# Cobalamin and iron deficiency still presents a challenge in hereditary hemorrhagic telangiectasia

## TL;DR

This study explores the prevalence of cobalamin and iron deficiency in patients with hereditary hemorrhagic telangiectasia (HHT), finding that while true cobalamin deficiency is not more common than in the general population, low-normal levels are frequent and may be linked to gastrointestinal issues.

## Contribution

This is the first study to investigate cobalamin deficiency in HHT patients and its association with gastrointestinal lesions.

## Key findings

- True cobalamin deficiency is not more common in HHT patients than in the general population.
- Low-normal cobalamin levels are frequent in HHT patients and associated with gastrointestinal lesions.
- Many HHT patients with low-normal cobalamin levels report symptoms typically linked to deficiency.

## Abstract

Hereditary hemorrhagic telangiectasia (HHT) leads to fragile blood vessels, causing frequent bleeding and anemia. Treatment mainly addresses iron levels and substitution. Although cobalamin (vitamin B12) is routinely tested in chronic anemia, its role in HHT has not been studied until now. This study examined its prevalence and related symptoms in HHT patients. Data from HHT patients treated between July 2019 and November 2022 were analyzed. Patients with cobalamin levels under 400 pg/ml underwent further testing and questioning. Among 155 patients, 42% were anemic, and 45% had cobalamin levels below 400 pg/ml. However, only 7 patients had a confirmed deficiency. Still, many reported symptoms commonly but not specifically linked to cobalamin deficiency, even with low-normal levels. Gastrointestinal lesions were significantly associated with these low-normal values (p = 0.027). Furthermore, 59% of patients had iron deficiency, and 67% were not receiving iron therapy at the time of their visit. This study is the first to show that true cobalamin deficiency is not more common in HHT than in the general population, though low-normal levels are frequent. In case of unexplained symptoms, evaluating cobalamin levels should be taken into consideration.

The online version contains supplementary material available at 10.1038/s41598-025-13911-6.