Co-occurrence of moyamoya syndrome and Turner syndrome in a 4-year-old Sudanese girl: a rare case report.

BACKGROUND: Moyamoya syndrome (MMS) is a chronic cerebrovascular condition characterized by progressive stenosis of the internal carotid arteries and the development of fragile collateral vessels, producing the characteristic "puff of smoke" appearance on angiography. This syndrome is uncommon in African populations, with higher prevalence in East Asia, with reported incidence rates ranging from 0.43 to 2.3 per 100,000 populations. Its co-occurrence with Turner syndrome (TS) is exceptionally rare, with only a handful of cases reported globally. This report describes the clinical features, diagnostic challenges, and management constraints of TS-associated MMS in a 4-year-old Sudanese girl.

CASE PRESENTATION: A 4-year-old Sudanese girl was referred to the Elite Center for Genetic Services due to dysmorphic features consistent with TS and a history of recurrent transient ischemic attacks and right-sided hemiparesis. Clinical examination revealed an asymmetrical triangular face, depressed nasal bridge, epicanthal folds, low posterior hairline, webbed neck, wide elbow angles, and widely spaced nipples. Neurological assessment confirmed right-sided motor weakness of grade 3/5 in upper and lower limbs, with intact sensation. Hemoglobin electrophoresis excluded sickle cell disease. Brain MRI showed acute-on-chronic left hemispheric infarction. Magnetic resonance angiography (MRA) demonstrated bilateral internal carotid artery stenosis and characteristic collateral vessels, findings suggestive of moyamoya syndrome. Karyotyping confirmed monosomy X (45,X), establishing the diagnosis of Turner syndrome. Due to limited access to revascularization surgery in Sudan, conservative management was initiated with aspirin (5 mg/kg/day), physical therapy, hormonal evaluation, and multidisciplinary follow-up.

CONCLUSION: This case highlights the diagnostic and therapeutic challenges of managing rare neurogenetic syndromes in resource-limited, conflict-affected settings. Early recognition of the TS-MMS association, and differentiation from more common causes like sickle cell disease, is critical to reducing stroke recurrence and long-term disability in vulnerable pediatric populations.