[Analysis of MLC1 gene mutation in a Chinese family with megalencephalic leukoencephalopathy with subcortical cysts].

The clinical data of a patient with megalencephalic leukoencephalopathy (MLC) with subcortical cysts and her parents were collected. MLC1 gene mutation was detected by polymerase chain reaction and direct DNA sequencing. The patient presented with motor developmental delay and giant skull, and brain magnetic resonance imaging showed diffuse white matter swelling accompanied by subcortical cysts in bilateral frontal and parietal lobes. Gene sequencing identified two heterozygous mutations of MLC1, including missense mutation in exon 3 (c.217G>A, p.Gly73Arg) and splice site mutation in intron 9 (c.772-1G>C in IVS9-1). The patient's parents both had heterozygous mutation c.772-1G>C in IVS9-1 with normal phenotype. It can be presumed that c.772-1G>C in IVS9-1 comes from the parents, and c.217G>A (p.Gly73Arg) is a de novo mutation.