This study reports a boy with psychomotor retardation and epilepsy due to maternal phenylketonuria (PKU). The boy was admitted at the age of 20 months because of psychomotor retardation and epilepsy. He had seizures from the age of 1 year. His development quotient was 43. He presented with microcephaly, normal skin and hair color. Brain MRI scan showed mild cerebral white matter demyelination, broadening bilateral lateral ventricle and foramen magnum stricture. Chromosome karyotype, urine organic acids, blood amino acids and acylcarnitines were normal. His mother had mental retardation from her childhood. She presented with learning difficulties and yellow hair. Her premarriage health examinations were normal. She married a healthy man at age of 26 years. When she visited us at 28 years old, PKU was found by markedly elevated blood phenylalanine (916.54 μmol/L vs normal range 20-120 μmol/L). On her phenylalanine hydroxylase (PAH) gene, a homozygous mutations c.611A>G (p.Y204C) was identified, which confirmed the diagnosis of PAH-deficient PKU. Her child carries a heterozygous mutation c.611A>G with normal blood phenylalanine. Her husband had no any mutation on PAH. It is concluded that family investigation is very important for the etiological diagnosis of the children with mental retardation and epilepsy. Carefully clinical and metabolic survey should be performed for the parents with mental problems to identify parental diseases-associated child brain damage, such as maternal PKU.
该文报道1例因发育落后及癫癎而诊断为母性苯丙酮尿症(phenylketonuria, PKU)的患儿。患儿男, 1岁8个月时就诊, 发育落后, 1岁出现癫癎, 毛发黑, 头围小, 发育商为43, 脑MRI扫描显示白质髓鞘化发育落后, 双侧侧脑室增宽, 枕骨大孔狭窄。染色体核型正常, 血液氨基酸、酯酰肉碱谱及尿液有机酸正常。家族史调查发现患儿母亲自幼智力落后, 学习困难, 毛发色泽发黄, 26岁结婚, 婚前常规检查未见异常。患儿母亲于28岁来院检查, 血液氨基酸分析发现血液苯丙氨酸显著增高(916.54 μmol/L, 正常值20~120 μmol/L), 苯丙氨酸羟化酶(PAH)基因c.611A > G(p.Y204C)纯合突变, 为PAH缺陷导致的PKU患者。患儿为c.611A > G杂合突变携带者, 血液苯丙氨酸正常。患儿父亲健康, PAH基因未检出突变。建议对于不明原因智力障碍的患儿需进行详细的家族史调查, 对智力障碍的父母更需进行详细的临床及代谢分析, 以发现亲代疾病导致的儿童脑损害, 如母性PKU。