The first case of a child with a dopamine transporter deficiency associated with SLC6A3 in Russia

Background and aims: We report the first case of a child with a dopamine transporter deficiency associated with SLC6A3 in Russia. Methods: A study of an 1.5-year-old girl, included anamnesis, physical neurological examination, and analysis of instrumental and genetic tests. Results: The child from a closely related marriage. The disease debuted with torticollis at the age of two months. There were the regurgitation, fountain vomiting and muscle spasticity. Hyperkinesis such as choreoathetosis, oromandibular dystonia, axial muscle dystonia, dystonic tremor, and development delay were identified at age of four months. Neurological examination revealed a hypomimic face, violent protrusion of the tongue. The child was lethargic, often throws her head back. The girl cannot sit, roll over, make sounds, swallow the saliva. Massage could induce an arousal attack with a dystonic status. MRI of the brain: atrophic changes in the brain, hypoplasia of the corpus callosum. In May 2020, the girl had been ill with COVID-19, her condition worsened, hyperkinesis became more pronounced, expressed anxiety, and rare dystonic statuses appeared. DNA panel: detected in exon 10 of the SLC6A3 gene nucleotide substitution chr5-1409937-C-N, NM-001044.4: c.1297G> A, p. (Gly433Arg) in a homozygous state. Conclusion: Dopamine transporter deficiency syndrome associated with SLC6A3 (DTDS) is a very rare complex movement disorder with a continuum that ranges from classic DTDS with early onset in the first six months to atypical DTDS with later onset in childhood, adolescence. According to the results of the examination, the patient has infant parkinsonism-dystonia type 1, homozygous gene carriage.