Indirect evaluation of amyloid deposition by ultrasonography and its relationship with MEFV gene mutation in FMF patients

Objective: The most significant complication in familial mediterranean fever (FMF) patients is dysfunction and organ failure developing depending on amyloid deposition in organs. The golden standard for showing amyloid deposition is the biopsy; however, tissue stiffness was examined by shear wave elastography as a non-invasive method in a restricted number of studies conducted, and it is considered that amyloid deposition can be shown indirectly. In our study, we aimed to indirectly evaluate amyloid deposition in organs with Shear wave and Doppler ultrasonography and to reveal its relationship with MEFV gene mutation analysis.

Method: 42 FMF patients with normal thyroid and renal function tests and 35 participants with no FMF symptoms were included in our study. FMF patients were grouped depending on their MEFV mutation analyses. Thyroid, salivary glands, and renal parenchymal tissue stiffness were evaluated by shear wave elastography. Thyroidal artery and both renal artery resistances were evaluated by Doppler ultrasonography.

Results: Both parotis gland, thyroid and renal parenchymal stiffness and arterial vascular resistances in the patient group were found higher than the control group. A significant difference was not found in any parameters in classification based on gender. Tissue stiffness and vascular resistance values in the patient group with M694V homozygote mutation were found statistically significantly higher than the other mutation groups (p < 0.001).

Conclusion: Our study shows that identifying genetic mutation type in FMF patients will help determine possibly amyloidosis risk. Imaging of tissue stiffness by shear wave elastography and evaluation of vascular resistance by Doppler can be useful for routine screening of those patients.