Asparagine Synthetase Deficiency (ASNS)
Asparagine synthetase deficiency is an autosomal recessive disorder that is caused by pathogenic variants in the gene ASNS. It is a pan-ethnic disease with a higher carrier frequency among individuals of Sephardic Jewish ancestry. This neurometabolic disorder causes congenital microcephaly, severe encephalopathy, progressive brain atrophy, intractable seizure disorder, global developmental delay, and spastic quadriplegia. At the moment, too few patients have been reported to determine a genotype-phenotype correlation and the lack of an effective treatment results in early death, usually during infancy.
For information about carrier frequency and residual risk, please see the residual risk table.