迄今,仅报告6例先天性叶酸盐吸收不良症,均为女孩。其主要的临床特点是自婴儿期即持续而严重的大细胞贫血,常有腹泻、口腔溃疡和发育不良,其中4例有进行性中枢神经退行病变。因有2例为同胞,三个家庭为近亲婚配,提示可能为常染色体隐性遗传病。本文报告系第7例,为一7个月的土耳其女孩。父母否认有亲缘关系,生后5个月开始反复感染、口炎、腹泻、惊厥和生长迟缓,并有大细胞性贫血、粒细胞减少及血浆免疫球蛋白低下。经口服叶酸和VB_(12)治疗后,贫血、腹泻及惊厥等一度缓解。但2个月后又出现顽固惊厥,严重智力低下。CT检查示枕叶皮质、基底神经节钙化。血浆与脑脊液叶酸盐浓度低下,提示为先天性叶酸盐吸收不良症,且血浆蛋氨酸浓度降低。采用蛋氨酸、VB_(12)、叶酸治疗后, To date, only 6 cases of congenital folate malabsorption have been reported, both of which are girls. Its main clinical feature is persistent and severe large cell anemia from infancy, often with diarrhea, mouth ulcers and dysplasia, of which 4 cases of progressive central nervous system degeneration. Because there are 2 cases of siblings, three families of the close relatives of marriage, suggesting that autosomal recessive disease may be. This article reports the seventh case for a Turkish girl of seven months. Parents denied having a kinship, repeated infections at 5 months after birth, stomatitis, diarrhea, convulsions and growth retardation, with macrocytic anemia, neutropenia, and low plasma immunoglobulin. After oral folic acid and VB_ (12) treatment, anemia, diarrhea and convulsions once relieved. However, 2 months later stubborn convulsions, severe mental retardation. CT examination showed occipital cortex, basal ganglia calcification. Plasma and CSF folate concentrations are low, suggesting a congenital folate malabsorption and plasma methionine levels. Using methionine, VB_ (12), folic acid treatment,