SLC6A20 and Hyperglycinuria: We discovered that the proband and her mother had hyperglycinuria and the proband (II<sub>2</sub>), her sister (II<sub>3</sub>), and mother (I<sub>1</sub>) were found to carry the SLC6A20 gene exon NM_020208.3 sequence c.1072T > C heterozygous mutation, and the other family members (I<sub>2</sub>, II<sub>1</sub>, II<sub>4</sub>, III<sub>1</sub>, III<sub>2</sub>) did not carry the genetic mutation.