How is Hyper-IgD Syndrome / Hyperimmunoglobulinemia D With Recurrent Fever (HIDS) diagnosed?

Hyper-IgD Syndrome (HIDS), also known as Mevalonate Kinase Deficiency (MKD), is diagnosed through a combination of clinical assessment, elevated serum IgD levels, and definitive molecular genetic testing for mutations in the MVK gene. Because symptoms often mimic common infections, many patients endure a significant "diagnostic odyssey" before reaching a specialist who recognizes this rare autoinflammatory condition.

How is Hyper-IgD Syndrome diagnosed?

The diagnostic process for Hyper-IgD Syndrome typically begins with a detailed medical history focusing on recurrent fevers starting in early childhood. Doctors look for associated symptoms such as lymphadenopathy, abdominal pain, and skin rashes. Because Hyper-IgD Syndrome is rare, it is often misdiagnosed as recurrent viral infections or periodic fever syndromes like PFAPA (Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis).

What tests confirm Hyper-IgD Syndrome?

Confirmation of Hyper-IgD Syndrome relies on objective laboratory evidence to support clinical suspicion:

• Serum Immunoglobulin D levels: Most patients exhibit elevated IgD levels, though this is not present in all cases.


• Mevalonic acid levels: Urinary excretion of mevalonic acid is often significantly increased during febrile episodes.


• Genetic testing: The gold standard for confirming Hyper-IgD Syndrome is the identification of biallelic (two) pathogenic variants in the MVK gene via DNA sequencing.

Which specialists should I consult?

If you suspect you or a loved one has Hyper-IgD Syndrome, it is vital to seek care from a pediatric or adult rheumatologist or an immunologist specializing in autoinflammatory diseases. These specialists are best equipped to distinguish Hyper-IgD Syndrome from other periodic fever syndromes like Familial Mediterranean Fever (FMF) or TRAPS, which require different management strategies.

Why is the diagnostic journey so difficult?

The rarity of Hyper-IgD Syndrome means many primary care physicians may never see a case in their career. It is common for patients to spend years seeking answers, facing multiple hospitalizations and unnecessary procedures. If your current medical team is unfamiliar with this condition, do not hesitate to seek a second opinion at a center of excellence for autoinflammatory disorders.

Next steps

• Consult a board-certified rheumatologist or immunologist experienced in autoinflammatory diseases.


• Request genetic counseling to discuss MVK gene testing and inheritance patterns.


• Connect with the 6 community members on DiseaseMaps.org to share experiences and find regional specialists.


• Keep a detailed "fever diary" documenting the onset, duration, and associated symptoms of each episode.

Medical disclaimer: This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Hyper-IgD Syndrome


• Orphanet: Mevalonate kinase deficiency


• OMIM (Online Mendelian Inheritance in Man): Mevalonate Kinase Deficiency


• Auto-Inflammatory Alliance: Patient resources for HIDS/MKD