Ten Novel Mutations in Chinese Patients with Megalencephalic Leukoencephalopathy with Subcortical Cysts and a Long-Term Follow-Up Research.
OBJECTIVE
Megalencephalic leukoencephalopathy with subcortical cysts (MLC, OMIM 604004) is a rare neurological deterioration disease. We aimed to clarify clinical and genetic features of Chinese MLC patients.


METHODS
Clinical information and peripheral venous blood of 20 patients and their families were collected, Sanger-sequencing and Multiple Ligation-dependent Probe Amplification were performed to make genetic analysis. Splicing-site mutation was confirmed with RT-PCR. UPD was detected by haplotype analysis. Follow-up study was performed through telephone for 27 patients.


RESULTS
Out of 20 patients, macrocephaly, classic MRI features, motor development delay and cognitive impairment were detected in 20(100%), 20(100%), 17(85%) and 4(20%) patients, respectively. 20(100%) were clinically diagnosed with MLC. 19(95%) were genetically diagnosed with 10 novel mutations in MLC1, MLC1 and GlialCAM mutations were identified in 15 and 4 patients, respectively. Deletion mutation from exon4 to exon9 and a homozygous point mutation due to maternal UPD of chromosome22 in MLC1 were found firstly. c.598-2A>C in MLC1 leads to the skip of exon8. c.772-1G>C in MLC1 accounting for 15.5%(9/58) alleles in Chinese patients might be a founder or a hot-spot mutation. Out of 27 patients in the follow-up study, head circumference was ranged from 56cm to 61cm in patients older than 5yeas old, with a median of 57cm. Motor development delay and cognitive impairment were detected in 22(81.5%) and 5(18.5%) patients, respectively. Motor and cognitive deterioration was found in 5 (18.5%) and 2 patients (7.4%), respectively. Improvements and MRI recovery were first found in Chinese patients. Rate of seizures (45.5%), transient motor retrogress (45.5%) and unconsciousness (13.6%) after head trauma was much higher than that after fever (18.2%, 9.1%, 0%, respectively).


CONCLUSIONS
It's a clinical and genetic analysis and a follow-up study for largest sample of Chinese MLC patients, identifying 10 novel mutations, expanding mutation spectrums and discovering clinical features of Chinese MLC patients.
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Binbin
B
Cao
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Huifang
H
Yan
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.|Department of Pediatrics, Beijing Tian Tan Hospital, Capital Medical University Beijing 100050, China.
Mangmang
M
Guo
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Han
H
Xie
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Ye
Y
Wu
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Qiang
Q
Gu
Department of Radiology, Peking University First Hospital, Beijing 100034, China.
Jiangxi
J
Xiao
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.|Department of Neurology, Shanxi Dayi Hospital, Taiyuan 030000, Shanxi Province, China.
Jing
J
Shang
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Yanling
Y
Yang
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Hui
H
Xiong
Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China.
Zhengping
Z
Niu
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Xiru
X
Wu
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Yuwu
Y
Jiang
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Jingmin
J
Wang
D044466:Asian People; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018797:Cell Cycle Proteins; D002675:Child, Preschool; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging / Q000235:genetics / Q000503:physiopathology; D003560:Cysts / Q000000981:diagnostic imaging* / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D020279:Hereditary Central Nervous System Demyelinating Diseases / Q000000981:diagnostic imaging* / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D000068079:Motor Disorders / Q000000981:diagnostic imaging / Q000235:genetics / Q000503:physiopathology; D009154:Mutation; D011506:Proteins / Q000235:genetics*; D017384:Sequence Deletion
D018797:Cell Cycle Proteins; C487620:HEPACAM protein, human; C425069:MLC1 protein, human; D008565:Membrane Proteins; D011506:Proteins