Novel SLC6A9 variants in an adult presenting with GlyT1 encephalopathy.
Only 14 individuals have been thus far described with GlyT1 encephalopathy due to biallelic variants in the SLC6A9 gene and the phenotypic picture is incomplete. Early mortality has been high, with only two known to survive into infancy. We report a 27-year-old individual who, to our knowledge, is the eldest person des...