Two Different MLC1 Variants Compounded with a Common Variant S93L in Japanese Patients of Megalencephalic Leukoencephalopathy with Subcortical Cysts

Abstract

Megalencephalic leukoencephalopathy with subcortical cysts (MLC; MIM#604004) is a rare congenital disorder of the cerebral white matter. Most MLC patients have MLC1 mutations which are inherited in an autosomal recessive manner. Since there is no established biomarker for MLC, genetic testing is necessary for a final diagnosis. We identified compound heterozygous mutations in two different Japanese patients having MLC. Both patients showed a common mutation of c.278C>T (p.Ser93Leu) in a heterozygous status. In addition, two different mutations (c.337_353delinsG and c.423+1G>A) were identified in the homologous alleles of the patients, respectively. Although these two variants were first identified in the Japanese population, they have since been reported in other Asian countries and might be founder mutations of the gene in Asian population.

Keywords

• sanger sequencing
• leukodystrophy
• macrocephaly