Asymptomatic moyamoya syndrome, atlantoaxial subluxation and basal ganglia calcification in a child with Down syndrome
A 10-year-old girl with Down syndrome was referred to the pediatric department from the ophthalmologic department of Ulsan University Hospital because both basal ganglia calcification was incidentally detected on a brain computed tomography (). She had been managed at the ophthalmologic clinic because of strabismus. Brain computed tomography (CT) was performed to identify whether her ophthalmologic manifestations, including esotropia of both eyes, amblyopia in the left eye, cyclotorsion of both eyes, and horizontal nystagmus, would result from brain parenchymal lesion.\nShe was born at Ulsan University Hospital. At that time, she showed typical features of Down syndrome, and was diagnosed with Down syndrome by the identification of 47,XX,+21 on the cytogenetic study. Echocardiography after birth, which was performed due to cardiac murmur, revealed a 6.3 mm sized perimembranous ventricular septal defect and two small sized atrial septal defects. She had been examined by regular follow-up echocardiography evaluation without surgery, and was presented with no symptoms associated with cardiac anomalies until the time of admission. She had moderate mental retardation with full scale intelligence quotient score of 44. Her parents stated that they had never noticed apparent neurologic symptoms of the patient, including transient motor weakness before the admission.\nOn physical examination at the time of admission, she showed typical features of Down syndrome, including hypertelorism, depressed nasal bridge, low-set ears, epicanthal folds, protruded tongue, small chin, and simian creases on both hands. On cardiac auscultation, systolic murmur was heard. On neurologic examination, she was fully alert and conscious. She showed esotropia of both eyes, but, the limitation of both eye movements was absent. She exhibited horizontal nystagmus, without vertical nystagmus. No obvious other abnormalities were revealed on the cranial nerve examination. Motor weakness of four extremities was absent, although muscle tone was slightly hypotonic. The deep tendon reflexes on both knees were slightly exaggerated, and Babinski sign was absent in both. On laboratory findings, we observed total calcium, 9.8 mg/dL; ionized calcium, 4.60 mg/dL; parathyroid hormone, 44.94 pg/mL; ceruloplasmin, 22 mg/dL; serum copper, 96 µg/dL; thyroid-stimulating hormone, 1.20 mIU/L; and free thyroxine, 1.49 ng/dL. Investigations for autoimmune (antinuclear antibody, antidouble strand DNA antibody, anticardiolipin antibodies, antiphospholipid antibodies, and antineutrophilic cytoplasmic antibody), prothrombotic (protein C, S, Factor V Leiden mutation, and antithrombin III) and metabolic (serum amino acid and urine organic acid) disorders were within normal limits. Echocardiography performed, during the admission, revealed 3-mm sized perimembranous ventricular septal defect with small to moderate left to right shunt, but good ventricular function. Brain magnetic resonance imaging and magnetic resonance angiography, which were performed during the admission, showed as follows; multiple tiny ischemic lesions in both frontal white matters, compression of the cervical cord due to displaced odontoid process at the level of C1, and severe stenosis of the bilateral internal carotid arteries with collaterals to the bilateral cerebral hemispheres (, ). Four vessels angiography revealed occlusion of the proximal portion of the right internal carotid artery, occlusion of the left internal carotid artery bifurcation and the left middle cerebral artery, transdural collaterals from the middle meningeal, the superficial temporal, and the occipital arteries, and hypertrophic right vertebral artery with prominent leptomeningeal collaterals to both cerebral hemispheres. Three dimensional cervical spine CT showed subluxation and rotation of C2 on C1 with spinal canal narrowing, and os odontoideum ().\nHer family moved to another province far from our hospital, several months after the evaluation. According to the telephone interview with the patient's mother, the patient had been doing well with no neurologic symptom and no special management during the 2 years since the admission to our hospital.