Case Report: A Patient Helps Diagnose Familial Mediterranean Fever

(click for larger image) Table 3: Simplified FMF Diagnosis Criteria⁵

Additionally, the K695R mutation, as well as multiple other clinically significant mutations in exon 10 (coding amino acids 577–781), alters the B30.2 domain, which interacts with caspase-1.¹¹ This region is an important functional site for pyrin because it regulates the interaction with caspase-1. FMF mutations involving exon 10 represent a gain of function and, in a pro-inflammatory manner, enhance the interaction with caspase-1 to cleave precursor forms of IL-1β and, thus, unleash the inflammatory response and regulation of apoptosis.³ Pyrin also has an anti-inflammatory role, promoting autophagy of cytoplasmic regulators of innate immunity, eventually promoting the regulation of the inflammatory response.³

As noted, we started the patient on colchicine, and after several weeks he had a transient, partial response.

At his follow-up appointment after his diagnosis, we discussed alternative therapies should colchicine not control his symptoms, although the patient was encouraged to continue his colchicine for at least six months before considering it a therapeutic failure. If symptoms don’t sufficiently respond to colchicine, we may implement a trial of anakinra or a different IL-1 inhibitor. It has been observed that 5–10% of patients may not respond (or are intolerant) to colchicine, so close clinical monitoring for a durable response is important.³

Although this case highlighted many different teaching points to the rheumatologist providing his care, it was ultimately patience—on the part of both the patient and his doctor—along with telltale photos that led to his diagnosis.

Taylor T. Faulk, MD, is an internal medicine resident at Keesler Medical Center at Keesler Air Force Base in Mississippi.

Matthew B. Carroll, MD, FACP, FACR, is a practicing rheumatologist at the Singing River Health System in Pascagoula, Miss.

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