Abstract: Objective To explore the pathogenic variation of hereditary leukoencephalopathy in two siblings of a family. Methods The clinical data of children and their families were collected. The peripheral blood DNA of the two siblings and their parents were extracted and genetic analysis and Sanger sequencing were performed by medical exon, whole exon and whole genome sequencing. Results The clinical manifestations of two siblings were consistent with Pelizaeus-Merzbacher-like disease. No pathogenic mutation was found in both medical exon sequencing and whole exon sequencing. However, whole-genome sequencing revealed that the two siblings had the same homozygous variant of c.- 167 A>T ( 5’UTR) exon 1 / 2 in the GJC 2 gene (NM- 020435 . 3 ), which was inherited in an autosomal recessive manner from their parents. Conclusion The c.-167A>T of GJC2 gene is a pathogenic variant of Pelizaeus-Merzbacher-like disease in two siblings of the family. Whole-genome sequencing can reveal an abnormality at this locus in the 5’UTR region.

Key words: whole genome sequencing; GJC 2 gene; 5’UTR region; Pelizaeus-Merzbacher-like disease