The proband had a homozygous missense CLN6 variant (p.L270P) in exon 7, and he presented with loss of speech, gait abnormality with loss of ambulation, spasticity in the lower limbs, and distal dyskinesia; and brain MRI revealed mild cerebellar atrophy (Jain et al., 2016). This evidence concerns the gene CLN6 and drug-induced dyskinesia.