Analysis of a family with asparagine synthase deficiency caused by ASNS gene mutation and literature review / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the clinical characteristics and gene variation of asparagine synthase deficiency that is caused by ASNS gene variation. Methods:In Department of Neuroendocrine Pediatrics, Affiliated Hospital of Qingdao University from October 2018 to February 2020, the clinical data of a family of asparagine synthase deficiency were analyzed retrospectively.The pathogenic mutation of the proband was screened by the full exon analysis technique.The pathogenic sites of candidate genes were determined by combining the phenotype of the proband.In the heterotopic spot of the proband, his parents and other family members were verified by Sanger sequencing.Meanwhile, the relevant literature database was consulted, and the reported ASNS mutation related cases were collected and reviewed. Results:The female with proband visited the hospital at the age of 4 months, and she had recurrent convulsions at the age of about 3 months.Physical examination showed that the child suffered from microcephaly, and mental and motor retardation.Meanwhile, video electroencephalogram examination displayed extensive moderate high amplitude spiny slow wave and sharp slow wave.Exon sequencing illustrated that the compound heterozygous variants of ASNS gene were c. 1211G>A (p.R404H) and c. 1643C>T (p.S548F), respectively.c.1211G>A was a known pathogenic variant, and c. 1643C>T was a new variant.The proband′s younger brother visited the hospital at the age of 2 months, developed convulsions at the age of 1 month, and developed mental and motor retardation.Electroencephalogram displayed that bilateral posterior head was dominant, multiple foci and extensive spike wave, and spike slow wave and fast wave were distributed.Sanger sequencing revealed the same ASNS compound heterozygous variants as the proband.Both of them died of status convulsion at the age of 7 months and 6 months, respectively. Conclusions:This study is helpful to further understand the clinical features of the disease and reveal a new pathogenic mutation of ASNS gene, so as to enrich the mutation spectrum of ASNS gene, thus providing important basis for clinical treatment and genetic counseling.