MOLECULAR-BASIS OF CYSTATHIONINE BETA-SYNTHASE DEFICIENCY IN PYRIDOXINE RESPONSIVE AND NONRESPONSIVE HOMOCYSTINURIA
MOLECULAR-BASIS OF CYSTATHIONINE BETA-SYNTHASE DEFICIENCY IN PYRIDOXINE RESPONSIVE AND NONRESPONSIVE HOMOCYSTINURIA
复制标题
DOI：
10.1093/hmg/2.11.1857
复制
发表时间：
1993-11-01
影响因子：
3.5
通讯作者：
SHIH, VE
中科院分区：
文献类型：
--
作者：
HU, FL;GU, Z;SHIH, VE
胱硫醚β-合酶（CBS）缺乏症是一种常染色体隐性遗传疾病，与多系统临床疾病相关。我们分析了患者RNA和基因组DNA的PCR扩增产物。CBS基因的整个编码区的直接测序揭示了外显子8中G-919到A的转换，导致蛋白质中Gly 307被Ser（G307 S）取代。在法国/苏格兰血统的患者L171的一个等位基因和爱尔兰血统的患者L198的两个等位基因中检测到突变。对L198的第8外显子进行扩增和测序，结果表明，L198的双亲均为G307 S杂合子。在表达实验中证明了突变的致病性。突变蛋白在大肠杆菌提取物中明显稳定，缺乏催化活性。第8外显子测序显示G307 S突变在另外5个家庭。所有患者均患有吡哆醇无反应性同型胱氨酸尿症。我们现在已经在52个不同种族背景的明显无关的等位基因中的9个中观察到这种突变。所有9例患者均来自父母一方或双方具有凯尔特（爱尔兰/英格兰/苏格兰/法国）血统的患者。在我们的系列中，在50%（18个中的9个）的凯尔特等位基因中检测到G307 S突变。在外显子8中发现的第二个突变是1278 T突变，其先前在吡哆醇应答患者的一个等位基因中描述。在吡哆醇无反应患者的一个等位基因和吡哆醇反应患者的两个等位基因中检测到这种错义突变。后者表明1278 T可能与吡哆醇反应性有关。
Cystathionine beta-synthase (CBS) deficiency is an autosomal recessive disorder associated with multisystem clinical disease. We analyzed PCR amplified products from patients' RNA and genomic DNA. Direct sequencing of the entire coding region of the CBS gene revealed a G-919 to A transition in exon 8, resulting in replacement of Gly 307 by Ser (G307S) in the protein. The mutation was detected in one allele of patient L171 of French/Scottish ancestry and in both alleles of patient L198 of Irish ancestry. Amplifying and sequencing exon 8 from the genomic DNA showed that both parents of L198 were heterozygotes for G307S. The pathogenicity of the mutation was demonstrated in an expression experiment. The mutant protein was apparently stable in E.coli extracts and lacked catalytic activity. Sequencing of exon 8 revealed the G307S mutation in five additional families. All patients have pyridoxine nonresponsive homocystinuria. We have now observed this mutation in 9 of 52 apparently unrelated alleles of varied ethnic backgrounds. All 9 are from patients with Celtic (Irish/English/Scottish/French) ancestry in either one or both parents. The G307S mutation was detected in 50% (9 of 18) of the Celtic alleles in our series. The second mutation found in exon 8 is the 1278T mutation, which was described previously in one allele of a pyridoxine responsive patient. This missense mutation was detected in one allele of a pyridoxine nonresponsive patient and in both alleles of a pyridoxine responsive patient. The latter suggests that 1278T is probably associated with pyridoxine responsiveness.