Hereditary Dopamine Transporter Deficiency Syndrome: Challenges in Diagnosis and Treatment.
Hereditary dopamine transporter deficiency syndrome (DTDS) is a neurotransmitter disorder caused by a defect in the neuronal uptake of dopamine. To date, 20 patients are reported in the literature, and we present 2 additional patients with DTDS harboring novel homozygousSLC6A3gene mutations. Patient A is an 8-month-old male with neonatal-onset hypotonia, who developed orolingual dyskinetic movements and oculogyric crises after 4 months of age, with evolution to status dystonicus episodes. Patient B is a 4-year-old male who also had hypotonia since birth, with additional severe limb contractions and oculogyric crises after the age of 3 months, with a misdiagnosis of epileptic encephalopathy. Both patients had consanguineous parents and similar cerebrospinal fluid (CSF) neurotransmitter profiles with elevated homovanillic acid and increased the ratio of homovanillic acid to 5-hydroxyindoleacetic acid. Diagnostic delay is 4 months, and 3 years 9 months, respectively. Treatment response to levodopa is poor. Early infantile-onset progressive dystonia with oculogyric crises, hypotonia, developmental delay, and CSF neurotransmitter profile led to a diagnosis of DTDS in these two patients. Management of hyperkinetic movement disorder, status dystonicus, and feeding difficulties are challenging. Detailed phenotyping of individual patients along with treatment response should provide insight into dopamine homeostasis.
Department of Pediatric Metabolism, Hacettepe University Ihsan Dogramaci Children's Hospital, Ankara, Turkey.
Yilmaz
Y
Yildiz
Department of Pediatric Metabolism, Hacettepe University Ihsan Dogramaci Children's Hospital, Ankara, Turkey.
Emine
E
Pektas
Department of Pediatric Metabolism, Hacettepe University Ihsan Dogramaci Children's Hospital, Ankara, Turkey.
Aysegul
A
Tokatli
Department of Pediatric Neurology, Hacettepe University Ihsan Dogramaci Children's Hospital, Ankara, Turkey.
Goknur
G
Haliloglu
D002675:Child, Preschool; D002658:Developmental Disabilities / Q000175:diagnosis / Q000235:genetics / Q000628:therapy; D050483:Dopamine Plasma Membrane Transport Proteins / Q000172:deficiency* / Q000235:genetics; D006801:Humans; D007223:Infant; D008297:Male; D008661:Metabolism, Inborn Errors / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy*
D050483:Dopamine Plasma Membrane Transport Proteins