Mabry C C
Department of Pediatrics, University of Kentucky, Lexington 40536.
Ann Clin Lab Sci. 1990 Nov-Dec;20(6):393-7.
Screening newborns for phenylketonuria (PKU) is a mandatory practice based on measuring a raised blood phenylalanine level. Many factors influence the rate of blood phenylalanine rise so that there are many pitfalls in detecting the 1:10,000 affected infant. About one percent of all babies tested proves to be "false positives." Two-thirds of those with persistent hyperphenylalaninemia prove to have classic PKU. Non-classic PKU with less intense, persistent hyperphenylalaninemia is due to different alterations in the enzyme, phenylalanine hydroxylase. Additionally, about one percent of the confirmed positive patients is due to either a defect in the synthesis or regeneration of the cofactor, tetrahydrobiopterin; these latter forms are not amenable to treatment with the low phenylalanine diet. Screening programs have developed directives regarding the timing and conditions for obtaining the specimens for testing. Specific confirmatory tests of those with positive results must be performed. Even so, about one in 70 affected babies is "missed," resulting in mental retardation, seizures, and neurologic deficits.
对新生儿进行苯丙酮尿症（PKU）筛查是一项基于检测血液中苯丙氨酸水平升高的强制性措施。许多因素会影响血液中苯丙氨酸水平升高的速率，因此在检测每10000名患病婴儿时存在许多陷阱。所有接受检测的婴儿中约有1%被证明是“假阳性”。持续性高苯丙氨酸血症患者中有三分之二被证明患有典型PKU。非典型PKU表现为较轻、持续性高苯丙氨酸血症，是由苯丙氨酸羟化酶的不同改变所致。此外，约1%确诊为阳性的患者是由于辅因子四氢生物蝶呤合成或再生缺陷；后一种类型不适合采用低苯丙氨酸饮食治疗。筛查项目已制定了关于获取检测标本的时间和条件的指导方针。对检测结果呈阳性的患者必须进行特定的确诊试验。即便如此，每70名患病婴儿中仍约有1名被“漏检”，从而导致智力发育迟缓、癫痫发作和神经功能缺损。
