Allen R J, Brunberg J, Schwartz E, Schaefer A M, Jackson G
Division of Pediatric Neurology, University of Michigan Medical School, Ann Arbor, USA.
Acta Paediatr Suppl. 1994 Dec;407:83-5. doi: 10.1111/j.1651-2227.1994.tb13460.x.
MPKU pregnancies, with or without dietary treatment to reduce maternal plasma phenylalanine (phe), show variable, increased non-physiologic levels, as the putative cause of fetal teratogenicity. Cerebral dysgenesis with clinical neonatal microcephaly and congenital heart disease indicates altered organ morphogenesis. Although there is not an established precise relationship between maternal phe levels and outcome, dietary restriction before or early in gestation is universally advised. Both human experience and animal research have suggested differential organ responses to high and low phe levels. Structural microencephaly may be due to reduced brain volume or abnormal regional brain development. Infants in MPKU are also at risk to develop PKU. Microencephaly was evident by MRI in 8 of 21 infants born to 12 MPKU mothers; 2 infants of one mother developed PKU. All levels of gestational plasma phe were associated with otherwise structurally normal infant microencephalic brains appropriate for age in myelination. CHD occurred in one microencephalic infant of a classic MPKU treated in the first trimester. Maternal, cord and neonatal plasma phenylalanine at delivery did not correlate with teratogenic effects. Only untreated 'classic' MPKU fetal effects appear predictable.
患有苯丙酮尿症（PKU）的孕妇，无论是否接受饮食治疗以降低母体血浆苯丙氨酸（phe）水平，都会出现可变的、非生理性升高的水平，这被认为是胎儿致畸性的原因。伴有临床新生儿小头畸形和先天性心脏病的脑发育不全表明器官形态发生改变。尽管母体苯丙氨酸水平与结局之间尚未建立精确的关系，但普遍建议在妊娠前或妊娠早期进行饮食限制。人类经验和动物研究均表明，不同器官对高苯丙氨酸水平和低苯丙氨酸水平的反应不同。结构性小头畸形可能是由于脑容量减少或局部脑发育异常所致。患有苯丙酮尿症的婴儿也有患苯丙酮尿症的风险。在12名患有苯丙酮尿症的母亲所生的21名婴儿中，有8名婴儿通过MRI检查发现明显的小头畸形；一位母亲的2名婴儿患了苯丙酮尿症。所有妊娠血浆苯丙氨酸水平均与在髓鞘形成方面与年龄相符的结构正常的婴儿小头畸形脑有关。一名在孕早期接受治疗的典型苯丙酮尿症患者所生的小头畸形婴儿患有先天性心脏病（CHD）。分娩时母体、脐带和新生儿血浆苯丙氨酸水平与致畸作用无关。只有未经治疗的“典型”苯丙酮尿症胎儿的影响似乎是可预测的。
