肾上腺脑白质营养不良的分子诊断(附2例报告)

Molecular diagnosis of adrenoleukodystrophy

目的 探讨肾上腺脑白质营养不良 (AL D)的分子诊断方法。方法 在临床诊断的基础上 ,从 2名患者外周血提取白细胞总 RNA ,进行反转录后 ,用 PCR方法分四段扩增 AL D基因编码区。纯化 PCR产物 ,并对其进行序列测定。查出突变位点后 ,对患者家系成员的基因组 DNA进行 PCR-限制性酶切分析。结果 患者 A的 AL D基因第 2 80位密码子发生 CGC→ CTC改变 ,使原来编码的精氨酸被亮氨酸取代 (R2 80 L突变 ) ;患者 B的 AL D基因第 5 0 8位密码子发生了 CCC→ CTC改变 ,使正常的脯氨酸被亮氨酸替换 (P5 0 8L 突变 )。两个突变通过酶切分析和家系调查得到进一步确证。结论 建立了 AL D的分子诊断技术 ,并在中国人 AL D患者发现了两个新的 AL D基因突变。

Objective To establish the method for the molecular diagnosis of adrenoleukodystrophy.Methods On the basis of clinical diagnosis,total RNA was isolated from the peripheral blood of 2 patients.After reverse transcription,the coding region of ALD gene was amplified in 4 segments by PCR.The PCR products were purified and directly sequenced.The genomic DNA of the patients family members was analyzed by PCR restrictive digestion.Results A change of CGC→CTC was found at codon 280 of patient As ALD gene,resulting in the replacement of arginine by leucine.A mutation of CCC→CTC was detected at codon 508 of patient Bs ALD gene,accompanied by the substitution of proline by leucine.The two mutations were confirmed through restriction analysis and pedigree study.Conclusion The molecular diagnostic technique for adrenoleukodystropy was established and two novel ALD mutations were identified in Chinese ALD patients.