For GlyT2, it was shown that homozygous (or compound heterozygous) nonsense, frameshift, and function-impairing missense mutations of the GlyT2 gene result in hyperekplexia [91,92,93], thus mimicking the consequences of a loss-of-function mutation in the glycine receptor genes GLRA1 or GLRB [94]. Here, SLC6A5 is linked to hyperekplexia.