Dworniczak B, Grudda K, Stümper J, Bartholomé K, Aulehla-Scholz C, Horst J
Institut für Humangenetik der Universität, Münster, Federal Republic of Germany.
Genomics. 1991 Jan;9(1):193-9. doi: 10.1016/0888-7543(91)90238-a.
By direct sequence analysis of 94 mutant phenylalanine hydroxylase alleles using polymerase chain reaction-based techniques, we identified a C to T transition in exon 7 of the human phenylalanine hydroxylase gene that is associated with RFLP haplotypes 1 and 4. A leucine for proline substitution at position 281 can be predicted from the nucleotide sequence of the mutant codon. Expression analysis in cultured mammalian cells after site-directed mutagenesis proved that the base substitution is a disease causing gene lesion. Dot-blot hybridization analysis using allele-specific oligonucleotides revealed that 25% of all mutant haplotype 1 alleles in the German population bear this mutation. In addition, this mutation could be detected on one mutant haplotype 4 allele. The fact that this mutation is associated with only 25% of all mutant haplotype 1 alleles suggests that multiple mutations may be associated with this haplotype. The occurrence of several different mutations would be in agreement with the clinical heterogeneity observed in the group of patients whose PKU alleles belong to haplotype 1.
通过使用基于聚合酶链反应的技术对94个突变型苯丙氨酸羟化酶等位基因进行直接序列分析，我们在人类苯丙氨酸羟化酶基因的第7外显子中鉴定出一个C到T的转换，它与限制性片段长度多态性（RFLP）单倍型1和4相关。从突变密码子的核苷酸序列可以预测在第281位脯氨酸被亮氨酸取代。定点诱变后在培养的哺乳动物细胞中进行的表达分析证明，这种碱基替换是一种致病基因损伤。使用等位基因特异性寡核苷酸的点杂交分析显示，德国人群中所有突变型单倍型1等位基因的25%携带这种突变。此外，在一个突变型单倍型4等位基因上也能检测到这种突变。这种突变仅与所有突变型单倍型1等位基因的25%相关这一事实表明，可能有多种突变与该单倍型相关。几种不同突变的出现与苯丙酮尿症（PKU）等位基因属于单倍型1的患者群体中观察到的临床异质性相符。
