Case Report: Neonatal lethality caused by novel compound heterozygous missense variants of SLC6A9 gene

Background

The homozygous or compound heterozygous missense variants in the SLC6A9 gene (OMIM*601019) are associated with autosomal recessive glycine encephalopathy with normal serum glycine (OMIM#617301). Fewer than ten SLC6A9 variants have been reported to date. Neonates harboring pathogenic variants in the SLC6A9 gene exhibited a mortality rate of up to 75% during the first 7 months of life. We reported the first documented case of neonate death in China attributable to compound heterozygous missense SLC6A9 variants.