Moyamoya syndrome as a risk factor for stroke in Saudi children. Novel and usual associations

OBJECTIVE: To report on moyamoya syndrome (MMS) as a risk factor for stroke in a prospective and retrospective cohort of Saudi children. The usual and novel associations of MMS in this cohort will also be described.

METHODS: Children with stroke were evaluated at the Division of Pediatric Neurology at King Khalid University Hospital, College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia during the periods July 1992 to February 2001 (retrospective study) and February 2001 to March 2003 (prospective study). Investigations for suspected cases included hemostatic assays, biochemical, and serological tests. Neuroimaging included CT, MRI, magnetic resonance angiography (MRA), single photon computerized tomography (SPECT) brain scan and conventional cerebral angiography.

RESULTS: Moyamoya syndrome was the underlying risk factor for stroke in 6 (5.8%) of the 104 children (aged one month to 12 years). They were 4 females and 2 males. Their first cerebral ischemic event occurred at a mean age of 45 months (median = 44 months, range 17-66 months). In all 6 cases, MMS was associated with an underlying hematologic abnormality or other diseases. Protein C deficiency was identified in one girl and protein S deficiency in another. Two patients had respectively, sickle cell disease (SCD) and sickle cell-beta-thalassemia (S beta-thalassemia), which had been associated in the latter with membranous ventricular septal defect. Adams-Oliver syndrome (AOS, OMIM 100300) was associated with MMS in an 18-month-old girl. A 4-year-old boy had wrinkly skin syndrome (WSS, OMIM 278250) phenotype. The association of MMS and protein C deficiency was first reported in this cohort of patients, whereas the association of the syndrome with WWS and AOS has not, hitherto, been described. The 3 patients who had MMS associated with protein C deficiency, SCD, and AOS underwent successful revascularization surgery in the form of encephaloduroarteriosynangiosis.

CONCLUSION: Moyamoya syndrome constitutes an important risk factor of stroke in Saudi children. Comprehensive clinical evaluation and investigations, including screening for thrombophilia and neuroimaging studies, are required for the primary diagnosis of the disease and for unraveling other diseases associated with MMS. This will help in managing these patients and in guiding genetic counseling for their families.