目的:探讨日本人群CYP1B1和FOXC1基因突变的频率和位置。
方法:分子遗传学分析。
方法:从29个家庭的31名日本儿童青光眼(CG)患者中提取基因组DNA。我们检查了CYP1B,FOXC1和MYOC基因使用Sanger测序和全外显子组测序(WES)。
结果:对于CYP1B1,我们鉴定出了9个带有新突变的家族,p.A202T,p.D274E,p.Q340*,和p.V420G;其余突变先前已报道。当映射到CYP1B1蛋白结构时,所有突变似乎都通过引起结构畸形来影响CYP1B1的酶活性。5例患者为纯合子或复合杂合子,支持CG中CYP1B1突变的隐性遗传。相比之下,4例患者为CYP1B1突变杂合,提示调节区突变或强修饰的存在。对于FOXC1基因,我们发现了3个新的突变,p.Q23fs,p.Q70R,和p.E163*,所有这些都是在杂合状态下鉴定的。在这些CG患者中未发现MYOC基因突变。所有具有CYP1B1和FOXC1突变的个体均受到早发性CG的严重影响。在CYP1B1-中,FOXC1-,和MYOC阴性家庭,我们还搜索了通过WES报道的其他CG候选基因的变异,但是在这些基因中找不到任何突变。
结论:我们对29个CG家族的分析揭示了9个家族在CYP1B1基因中存在点突变,其中四名患者似乎是杂合子,提示存在复杂的致病机制。FOXC1似乎是CG的另一个主要致病基因,表明CYP1B1和FOXC1的组测序将有助于日本个体的CG诊断。
OBJECTIVE: To explore the frequency and positions of genetic mutations in CYP1B1 and FOXC1 in a Japanese population.
METHODS: Molecular genetic analysis.
METHODS: Genomic DNA was extracted from 31 Japanese patients with childhood glaucoma (CG) from 29 families. We examined the CYP1B, FOXC1, and MYOC genes using Sanger sequencing and whole-exome sequencing (WES).
RESULTS: For CYP1B1, we identified 9 families that harbored novel mutations, p.A202T, p.D274E, p.Q340*, and p.V420G; the remaining mutations had been previously reported. When mapped to the CYP1B1 protein structure, all mutations appeared to influence the enzymatic activity of CYP1B1 by provoking structural deformity. Five patients were homozygotes or compound heterozygotes, supporting the recessive inheritance of the CYP1B1 mutations in CG. In contrast, four patients were heterozygous for the CYP1B1 mutation, suggesting the presence of regulatory region mutations or strong modifiers. For the FOXC1 gene, we identified 3 novel mutations, p.Q23fs, p.Q70R, and p.E163*, all of which were identified in a heterozygous state. No mutation was found in the MYOC gene in these CG patients. All individuals with CYP1B1 and FOXC1 mutations were severely affected by early-onset CG. In the CYP1B1-, FOXC1-, and MYOC-negative families, we also searched for variants in the other candidate genes reported for CG through WES, but could not find any mutations in these genes.
CONCLUSIONS: Our analyses of 29 CG families revealed 9 families with point mutations in the CYP1B1 gene, and four of those patients appeared to be heterozygotes, suggesting the presence of complex pathogenic mechanisms. FOXC1 appears to be another major causal gene of CG, indicating that panel sequencing of CYP1B1 and FOXC1 will be useful for diagnosis of CG in Japanese individuals.