title: A Case of Homocystinuria Misdiagnosed as Moyamoya Disease: A Case Report.
abstract: BACKGROUND
  Homocystinuria is a hereditary disease caused by a defect in the enzymes involved in metabolizing methionine. Homocystinuria can influence many systems and may be mistaken for other diseases, including Moyamoya disease. Here, we report the case of a 10-year-old male patient with a diagnosis of Moyamoya disease who had been monitored for that for an extended period. The patient's diagnosis was changed to homocystinuria as a result of lens subluxation and cataract findings.
  
  
  METHODS
  A 10-year-old male patient presented with vomiting, headache, lethargy, muscular weakness, and eye redness. The patient was mentally retarded, his right pupil was hyperemic, and he had muscle weakness on his left side. In addition, his blood pressure was high. The patient's history included a diagnosis of Moyamoya. A neck and cranial computed tomography (CT) angiography showed no flow bilaterally past the bifurcation of the carotid artery. The patient's bilateral internal carotid arteries were determined to be occluded. It was considered that his eye findings could be compatible with a metabolic disease. On metabolic screening, the patient's homocysteine level was very high. In addition, a heterozygous A1298C mutation was identified in MTHFR. Therefore, the patient was started on a diet free from homocysteine and methionine. In addition, his treatment regimen included vitamins B12 and B6. With these treatments, the patient's complications regressed.
  
  
  CONCLUSIONS
  In cases of unusual vascular lesions, metabolic diseases must be considered. In homocystinuria, early diagnosis and treatment are important. Blood homocysteine levels can be returned to normal, and some complications can be prevented.
authors.affiliation: Department of Pediatrics, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors.forename: Meltem
authors.initials: M
authors.lastname: Erol
authors.affiliation: Department of Pediatrics, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors.forename: Ozlem Bostan
authors.initials: OB
authors.lastname: Gayret
authors.affiliation: Department of Pediatrics, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors.forename: Ozgul
authors.initials: O
authors.lastname: Yigit
authors.affiliation: Department of Ophtalmology, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors.forename: Kubra
authors.initials: K
authors.lastname: Serefoglu Cabuk
authors.affiliation: Department of Radiology, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Toksoz
authors.affiliation: Department of Pediatrics, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors.forename: Mahir
authors.initials: M
authors.lastname: Tiras
keywords: Lens Subluxation; Metabolic Disease; Moyamoya Disease