【摘要】 目的应用磁共振成像技术观察四氢生物蝶呤(BH4)缺乏症患儿脑白质的改变,以了解BH4缺乏对脑髓鞘发育的影响,为判断治疗效果提供影像学根据。方法BH4缺乏症患儿11例,年龄17周至4岁,其中9例经新生儿筛查发现,虽然经过低苯丙氨酸(Phe)饮食治疗将血Phe浓度控制在120～240μmol/L范围内,患者仍出现进行性肌张力低下和智力发育落后。所有患者均经尿蝶呤谱分析、BH4口服负荷试验及红细胞二氢蝶呤还原酶测定,确诊为BH4缺乏症。患儿用0.5T超导型MR仪进行头颅扫描。结果11例患儿均存在髓鞘发育延迟,其中额叶11例,枕叶8例,颞叶4例,顶叶3例,胼胝体发育不良6例。全部病例在T2WI上脑白质内均有弥漫性高信号病灶。结论所有BH4缺乏症患者都存在脑白质病变,推测这种损害不仅可能与高Phe血症有关,且与神经递质的合成障碍有关。更多还原

【Abstract】 Objective To observe the brain abnormalities of the white matter and myelination in patients with BH4 deficiency using MRI examination, and to further estimate the effect of treatment. Methods Eleven patients with BH4 deficiency aged 17 weeks to 4 years were observed, including 9 cases who were detected by newborn screening program. Although those patients were treated with low phenylalanine diet, and the blood phenylalanine 1evels maintained to 120-240 μmol/L, the patients presented progressive hypotonia, convulsion, and mental retardation. All cases were diagnosed as BH4 deficiency by analysis of urinary pterins profile, BH4 loading test, and determination of dihydropteridine reductase in RBC. The patients received MRI examination using a 0.5 T MR system. Results Delayed myelination was found in 11 cases （100%） in frontal lobe, 8 cases （72.2%） in occipital lobe, 4 cases （36.3%） in temporal lobe, and 3 cases （27.3%） in parietal lobe. Delayed myelination of corpus callosum could be found in 6 cases （54.5%）. There were abnormal diffuse high signals in the white matter on T₂WI in all cases. Conclusion Patients with BH4 deficiency demonstrate a high occurrence of brain abnormalities in the white matter. Those abnormalities are related not only with hyperphenylalaninemia, but also due to the decreased synthesis of neurotransmitters, such as L-Dopa and 5-HTP, all of these could be the reasons of adverse effect of the development of white matter.更多还原