Background: Genetic factors play an important role in the pathogenesis of moyamoya disease (MMD). Previous studies concentrated on familial MMD patients. In this study, we focused on family members of sporadic MMD patients, and aimed to gain a clearer understanding of the role that genetic factors play in MMD.
Methods: The immediate family members of MMD patients were initially screened by transcranial Doppler sonography (TCD) and positive cases were verified by magnetic resonance angiography (MRA).
Results: From July 2011 to March 2013, there were 527 MMD patients managed in our hospital, including 38 familial MMD cases. In this study, 285 immediate family members of 245 sporadic MMD patients were screened. Another 41 cases of familial MMD cases were identified, which included 21 family members and 20 corresponding sporadic MMD patients who had family members confirmed positive with MMD. As a result, the proportion of familial MMD patients increased from 7% (38/527) to 15% (79/527) in this period. For the main segments of the circle of Willis, Kappa values between TCD and MRA for the anterior cerebral arteries, middle cerebral arteries and posterior cerebral arteries were 0.91, 0.72, and 0.47, respectively. Familial cases confirmed by our screening showed a significantly higher percentage of asymptomatic patients (57%) compared with 9% from the control group who had a clear family history before.
Conclusions: Familial MMD patients may account for a higher percentage among all cases than previously thought. Some family members of MMD patients may also have MMD, but not have any obvious symptoms. Routine screening should be implemented for all family members of MMD patients to improve the detection rate for this part of the patient base. TCD has a high diagnostic agreement with MRA for MMD. TCD may be the preferred choice for screening because it is inexpensive and safe.