IgG4-RD: From Diagnostic Delays to Collective Action in Rare Disease Care

What happens when a disease can affect nearly any organ system, mimic other conditions and still be commonly misdiagnosed?

For many people living with IgG4-related disease (IgG4-RD), this is the reality. Yet awareness remains limited, contributing to delays that can have a significant impact on patients' lives.

This was at the center of a recent Amgen-hosted panel discussion, which brought together a patient, clinician and advocate/care partner to help journalists across Europe better understand the challenges of diagnosing and managing IgG4-RD, a disease characterized by inflammation and fibrosis.

A Long Road to Diagnosis

For Silvia, a woman from the Netherlands, receiving her IgG4-RD diagnosis took nearly 30 years-a reflection of the long and complex path many patients face. "My diagnosis took way too long. I have this very great wish for other people not to have to go through my journey. So other people are taken seriously at the start of their disease journey, not after 30 years," said Silvia.

"The typical path involves seeing at least four to five specialists and waiting four to five years to get a diagnosis and for many patients, the wait is far longer," said Katharine Provencher, director of Advocacy and Community Engagement at IgG4ward!, whose advocacy began after her husband was diagnosed with the disease.

For patients, delayed diagnosis can mean unchecked symptoms, increased uncertainty and the risk of unnecessary invasive procedures.^1,2

"In my husband's case, he was told he had stage four lung cancer," said Katharine, who added the majority of people she speaks to "has either been misdiagnosed with some sort of cancer, has had organs removed because they thought it was cancer or other autoimmune diseases."

Progress in Recognizing and Managing IgG4-RD

Professor Emma Culver, MD PhD, head of department for Hepatology, John Radcliffe Hospital and Translational Gastroenterology and Liver Unit, University of Oxford, shared the advancements that have helped shape a clearer framework for recognizing and managing the disease over the past two decades.

The publication of the International Consensus Guidance Statement on the Management and Treatment of IgG4-RD in 2015, followed by the 2019 ACR/EULAR Classification Criteria, has contributed to a more structured framework for recognizing and classifying IgG4-RD.

Greater understanding of disease-associated biomarkers, more robust diagnostic criteria and increasing awareness among clinicians are all contributing to that momentum.

However, Dr. Culver noted that progress in knowledge does not always translate into day-to-day clinical practice.

As IgG4-RD can affect multiple organ systems, better cross-specialty coordination and knowledge-sharing may help address the diagnostic challenges patients face.

"We need collaborative working between specialists to really enhance awareness and understanding of this [disease]," she said. "I've got a lot of hope for the future. I think we have to work collaboratively-all specialists, physicians, carers working together towards actually improving not just awareness, but also management of this disease."

For Silvia, the hope is simple: that others with IgG4-RD will not wait as long as she did for answers.

"The reason why I'm involved in patient advocacy is so I can ensure other patients are heard when they're speaking to their healthcare professionals," said Silvia.

Improving IgG4-RD Diagnosis and Patient Care

While significant progress has been made in the management of IgG4-RD, more work remains to be done.

Key takeaways from the panel included:

• Raising disease awareness: Events such as this panel discussion and IgG4-RD Awareness Month help raise awareness of the symptoms and experiences of those impacted by IgG4-RD. Organizations like IgG4ward! and the European Federation for IgG4-RD can bring this awareness to healthcare providers, patients, care partners and the general public.
• Enhancing multidisciplinary collaboration: Clinicians and other stakeholders must collaborate to share information and expertise, including identifying patterns of disease presentation.
• Listening to the patient voice: It is important to listen to lived experiences and symptoms as experienced by patients, to ensure management guidelines reflect a nuanced and holistic approach.

Watch the panel discussion here.

Amgen has provided support for certain IgG4ward! activities.

References

1. Hernandez-Barco Y, Park J, Wani R, et al.Diagnostic Journey, Clinical Burden, And Quality Of Life Of Patients With IGg4-Related Disease: Results Of A Cross-Sectional Survey Of Patients And Physicians In The United States [abstract]. Arthritis Rheumatol. 2025; 77 (suppl 9).
2. Zhou WL, Murray T, Cartagena L, et al.IgG4-Related Disease as Mimicker of Malignancy. Medicines. 2021;3:1904-1913.