Hereditary hemorrhagic telangiectasia is an inherited disease related to an alteration in angiogenesis, manifesting as cutaneous telangiectasias and epistaxis. As complications, it presents vascular malformations in organs such as the lung, liver, digestive tract, and brain. Currently, diagnosis can be made using the Curaçao criteria or by identifying the affected gene. In recent years, there has been an advance in the understanding of the pathophysiology of the disease, which has allowed the use of new therapeutic strategies to improve the quality of life of patients. This article reviews some of the main and most current evidence on the pathophysiology, clinical manifestations, diagnostic approach, screening for complications, and therapeutic options, both pharmacological and surgical.

Most rare diseases (RDs) encompass a diverse group of inherited disorders that affect millions of people worldwide. A significant proportion of these diseases are driven by functional haploinsufficiency, which is caused by pathogenic genetic variants. Currently, most treatments for RDs are limited to symptom management, emphasizing the need for therapies that directly address genetic deficiencies. Recent advancements in gene therapy, particularly with adeno-associated viruses (AAVs) and lipid nanoparticle-encapsulated messenger RNA (mRNA), have introduced promising therapeutic approaches. AAV vectors offer durable gene expression, extensive tissue tropism, and a safety profile that makes them a leading choice for gene delivery; however, limitations remain, including packaging size and immune response. In contrast, mRNA therapeutics, formulated in LNPs, facilitate transient protein expression without the risk of genomic integration, supporting repeated dosing and pharmacokinetic control, though with less long-term expression than AAVs. This review analyzes the latest developments in AAV and mRNA technologies for rare monogenic disorders, focusing on preclinical and clinical outcomes, vector design, and delivery challenges. We also address key regulatory and immunological considerations impacting therapeutic success. Together, these advancements in AAV and mRNA technology underscore a new era in RD treatment, providing innovative tools to target the genetic root of these diseases and expanding therapeutic approaches for patients who currently face limited medical options.

Immunoglobulin G4–related disease (IgG4-RD) is an uncommon fibro-inflammatory process characterized by the infiltration of tissues and organs and a typically dramatic response to glucocorticoids. Its relapsing–remitting course, multisystemic involvement, and variability in epidemiological and prognostic features pose a significant diagnostic challenge for clinicians. Despite their effectiveness in symptom relief, prolonged glucocorticoid use remains a challenge in IgG4-RD management, prompting the search for steroid-sparing alternatives. Although rituximab has recently demonstrated efficacy in the treatment of IgG4-RD, no consensus exists regarding the optimal maintenance regimen. The emergence of new B-cell–targeted therapies and other immunomodulators represents a promising step toward more personalized treatment approaches. In this review, we provide an updated and integrative overview of the emerging treatment strategies for IgG4-RD, highlighting future directions towards individualized management.

Background: Hereditary Hemorrhagic Telangiectasia (HHT) is a vascular autosomically inherited rare disease. Epistaxis (nose bleeds) is the most common symptom in HHT, leading to anemia and affecting the patient’s quality of life. In addition to epistaxis, gastrointestinal bleeding (GI), more often at older ages, may lead to severe anemia and the need for blood transfusions. Thus, finding drugs to control both types of bleeding is a primary necessity in HHT. Methods: A cross-sectional observational study was conducted in a series of 11 HHT patients treated with low tacrolimus doses (0.5–2 mg/day) on an off-label prescription basis. Patients showed refractory bleeding to previous treatments. The epistaxis severity score (ESS) and hemoglobin levels were the parameters used to evaluate the impact of tacrolimus. The occurrence of side effects was also recorded. Results: Tacrolimus was well tolerated in all of the patients except 2 (who stopped the treatment). The remaining patients tolerated the treatment, with a general improvement in their health condition. Epistaxis was significantly reduced when comparing the ESS before and after the treatment. Hemoglobin levels significantly increased, overcoming the anemia, during the course of the treatment. Conclusion: Tacrolimus at low doses should be considered as a promising treatment for epistaxis and gastrointestinal bleeding in HHT.

This document provides an updated overview of the molecular mechanisms underlying pulmonary fibrosis associated with Systemic Sclerosis (SSc). It summarizes current knowledge on how immune activation, vascular injury, and impaired tissue repair contribute to interstitial lung disease (ILD), which is the most serious and life-threatening complication of SSc. SSc is a rare autoimmune disorder involving vascular dysfunction and progressive fibrosis of the skin and internal organs. In the lungs, the interaction between immune and vascular abnormalities and excessive extracellular matrix deposition leads to irreversible structural damage. These processes occur through complex, multifactorial mechanisms that are only partially understood. The review examines recent evidence on the cellular mediators, signaling pathways, and epigenetic alterations involved in ILD-SSc pathogenesis. It also discusses the potential roles of genetic predisposition, environmental factors, and autoantibody profiles in disease heterogeneity. Finally, it highlights emerging therapeutic strategies that target these molecular mechanisms. This work aims to integrate these advances to provide a clearer understanding of the biological basis of SSc-associated pulmonary fibrosis and support the development of novel diagnostic and therapeutic approaches that may improve patient outcomes.

The availability of highly sensitive molecular tests for the detection of Clostridioides difficile in feces leads to overtreatment of patients who are probably only colonized. In this prospective study, the usefulness of fecal calprotectin (fCP) is evaluated in a cohort of patients with detection of toxigenic C. difficile in feces. Patients were classified by an infectious diseases consultant blinded to fCP results into three groups—group I, presumed Clostridioides difficile infection (CDI); group II, doubtful but treated CDI; and group III, presumed C. difficile colonization or self-limited CDI not needing treatment. One hundred and thirty-four patients were included. The median fCP concentrations were 410 (138–815) μg/g in group I, 188 (57–524) μg/g in group II, and 51 (26–97) μg/g in group III (26 cases); p < 0.05 for all comparisons. In forty-five out of 134 cases (33.5%), the fCP concentrations were below 100 µg/g. In conclusion, fCP is low in most patients who do not need treatment against C. difficile, and should be investigated as a potentially useful test in the management of patients with detected toxigenic C. difficile.