Meguro K, Fujita H, Ishida N, Akagi R, Kurihara T, Galbraith R A, Kappas A, Zabriskie J B, Toback A C, Harber L C
Rockefeller University Hospital.
J Invest Dermatol. 1994 May;102(5):681-5. doi: 10.1111/1523-1747.ep12374134.
The molecular defect of uroporphyrinogen decarboxylase (UROD) was examined in a patient with mild hepatoerythropoietic porphyria. To elucidate the UROD defect, we cloned UROD cDNAs from EBV-transformed lymphoblastoid cells of the proband using reverse transcriptase-polymerase chain reaction. Nucleotide sequence analysis of the cloned UROD cDNAs revealed two separate missense mutations, each occurring in a separate allele. One mutation was a Val134-->Gln transition, and was due to three sequential point mutations (T417G418T419-->CCA); the other mutation was a His220-->Pro transition (A677-->C). UROD phenotype studies demonstrated that the TGT-->CCA mutation was inherited from the father, and the A-->C mutation was inherited from the mother. In contrast to the null activity previously described for a mutant UROD from a patient with familial porphyria cutanea tarda, these mutant URODs had subnormal but substantial enzyme activities, when expressed in Chinese hamster ovary cells. This is the first demonstration of a mutation caused by three sequential base substitutions.
对一名轻度肝红细胞生成性卟啉症患者的尿卟啉原脱羧酶（UROD）分子缺陷进行了检测。为阐明UROD缺陷，我们使用逆转录酶-聚合酶链反应从先证者的EB病毒转化淋巴母细胞中克隆了UROD cDNA。对克隆的UROD cDNA进行核苷酸序列分析，发现两个不同的错义突变，每个突变分别发生在一个单独的等位基因中。一个突变是Val134→Gln转换，由三个连续的点突变（T417G418T419→CCA）引起；另一个突变是His220→Pro转换（A677→C）。UROD表型研究表明，TGT→CCA突变来自父亲，A→C突变来自母亲。与先前描述的家族性迟发性皮肤卟啉症患者的突变UROD的无活性不同，这些突变UROD在中国仓鼠卵巢细胞中表达时，酶活性虽低于正常水平但仍有相当活性。这是首次证明由三个连续碱基替换引起的突变。
