一例巨颅伴皮层下海绵样囊肿性脑白质病患儿的MLC1基因突变分析

Identification of a novel MLC1 mutation in a Chinese patient affected with megalencephalic leukoencephalopathy with subcortical cysts

目的探讨一例巨颅伴皮层下海绵样囊肿性脑白质病（megalencephalic leukoencephalopathy with subcorti calcysts，MLC）患儿临床特征与MLC1基因突变情况，为其家庭提供遗传咨询。方法收集患儿及其父母临床资料并提取外周血DNA，对MLC1基因编码区及侧翼序列进行聚合酶链反应扩增后测序。结果患儿生后出现头围异常增大，运动认知落后，头颅MRI示双侧大脑半球白质弥漫异常信号，测序发现MLC1第2外显子c．177-c180delC纯合型缺失突变。患儿父母为相同位点杂合型突变、表型正常携带者。结论该MLC患儿存在MLC1基因纯合型突变，突变基因来源于父母。

Objective To detect potential mutation of MLC1 gene in a child affected with megalencephalic leukoencephalopathy with subcortical cysts （MLC）. Methods Clinical symptoms of the patient were retrieved. Peripheral blood DNA samples from the patient, her parents and healthy controls were collected. Potential mutation of the MLC1 gene was detected by polymerase chain reaction and Sanger sequencing. Results The patient presented with severe motor developmental delay and a giant skull. Magnetic resonance scan showed diffuse white matter swelling in bilateral hemispheres. DNA sequencing identified a novel homozygous c. 177-c. 180delC mutation of the MLC1 gene. The parents of the patient both carried a heterozygous mutation c. 177-c. 180delC but had a normal phenotype. Conclusion A novel MLC1 mutation c. 177-c. 180delC has been identified in a patient with MLC. The mutation is presumably disease causing and has derived from parents who are both carriers.