DISEASE: Asparagine synthetase deficiency (ASNSD) [MIM:615574]: An inborn error of asparagine biosynthesis that results in a severe neurologic disorder characterized by microcephaly, severely delayed psychomotor development, progressive encephalopathy, cortical atrophy, and seizure or hyperekplexic activity. {ECO:0000269|PubMed:24139043}. Note=The disease is caused by mutations affecting the gene represented in this entry.