Leber遗传性视神经病变线粒体DNA三个原发性突变位点的研究

摘要

Objective To screen for genetic mutations in 35 patients with Leber's hereditary optic neuropathy (LHON).Methods Polymerase chain reaction and DNA sequencing were used to screen for the presence of mitochondrial DNA mutations.Results The total detection rate of top 3 common LHON mutations were 20.0％,which included 6 cases of ND4 11778 G＞A,1 case of ND1 3460 G＞A.NoND6 14484 T＞C mutation was detected.A ND4 G11719A synonymous mutation was found in all patients.In addition,21 other mutations were discovered among 23 patients,among which 13 had a single mutation,8 had a second mutations,and 2 had a third mutation.Among the 21 mutations,ND4 11778 G＞A had a frequency of 28.6％(6/21).ND1 3552 T＞A,ND6 14470 T＞C,ND4 11794 T＞C,ND1 3497 C＞T and 3644 T＞C respectively had a frequency of 19.0％(4/21).19.0％(4/21),14.3％(3/21),9.5％(2/21) and 9.5％(2/21).Among the 3 patients who harbored a ND4 11794 T＞C mutation,2 were heteroplasmic and one was homoplasmic in nature.Conclusion The ND4 11778 G＞A mutation is common in the Top "3"primary mutations of patients with LHON.Candidate LHON mutation ND1 3552 T＞ A or ND1 3644 T＞C resulted in LHON pathogenesis as single or synergistic effect.The visual impairment at onset of the disease with candidate mutation were better than the eyes with the ND4 11778 G＞A mutation.%目的 通过对Leber遗传性视神经病变(Leber's hereditary optic neuropathy,LHON)线粒体DNA ND4 11778G＞A、ND1 3460G＞A和ND6 14484T＞C 3个原发性突变位点序列分析,阐明LHON患者发病的分子机理.方法 PCR扩增35例患者的上述3个原发性突变位点所在的区段,PCR产物直接测序分析.结果 35例患者中,6例存在ND4 11778 G＞A突变位点,1例存在ND1 3460 G＞A突变位点,未检出ND6 14484 T＞C突变位点,3个原发性突变位点的检出率为20.0％(7/35).35例患者均存在ND4 11719G＞A同义突变,除此突变位点外,23例(65.7％)患者共计筛出21个突变位点,2种突变类型.其中13例患者存在单个突变位点,8例存在2个突变位点,2例存在3个突变位点.21个突变位点中,ND4 11778G＞A突变频率最高,为28.6％(6/21); ND1 3552 T＞A、ND6 14470 T＞C、ND4 11794 T＞C、ND1 3497 C＞T和3644 T＞C位点突变频率依次为19.0％(4/21)、19.0％(4/21)、14.3％(3/21)、9.5％(2/21)和9.5％(2/21).3例存在ND4 11794 T＞C突变位点的患者,2例为异质性突变,1例为同质性突变.结论 LHON患者线粒体DNA ND4 11778G＞A、ND1 3460G＞A和ND6 14484T＞C 3个原发性致病突变中,以ND4 11778 G＞A为主；继发性突变位点ND1 3552 T＞A或ND1 3644 T＞C单独或协同原发性突变位点ND4 11778 G＞A导致LHON的发生,与单纯携带ND4 11778 G＞A的患者相比视力受损较弱.