Background/Aims
Moyamoya disease (MMD) is an arteriopathy presenting with stroke. MMD is uncommon with European ancestry (1 per 1,100,000) but has a high prevalence (1-16 per 100,000) in East Asian ancestry (Chinese, Japanese, Korean) with a genetic risk factor (RNF213 variant). We aimed to characterise MMD in a New Zealand cohort to determine if there was any increase in people of māori or pacific ancestry.
Methods
Patients with MMD were identified from 15 years of electronic hospital records from northern New Zealand, which has a population of 1.8 million of whom 17% are māori and 22% are pacific. MMD was defined by radiological criteria with other causes excluded (autoimmune disease, prior meningitis, brain neoplasm, trisomy 21, neurofibromatosis or previous radiotherapy).
Results
64 patients were identified with arteriopathy and 26 had exclusion diagnoses leaving 38 with probable MMD (23 women, mean age [SD] 41.8 [16.8] years). 20 (53%) had Māori or Pacific ancestry (15 women, mean age [SD] 39.7 [15.9] years), and 18 were of other ethnic groups (8 women, mean age [SD] 44.1 [17.5] years, 12 East Asian and 6 NZ European). The prevalence of MMD in māori was 1.8 per 100,000 people and in pacific people 5 per 100,000. Māori and pacific patients tested negative for RNF213.
Conclusions
MMD is more common in people of Māori and Pacific ancestry, which may be related to historic migration of these populations from South East Asia. We plan to further investigate this link by performing whole genome sequencing in this cohort.