Congenital metabolism diseases of neurotransmitters in pediatric neurology: Clinical description and neurological tracing of a group of patients

Introduction: The neurological manifestations of congenital metabolism diseases of aminergic neurotransmitters (NT) are diverse. The autosomal dominant Dopa-responsive dystonia (DRD), with deficiency of GTP cyclohydrolase1 (GTPCH1), is the most common type, with a satisfactory response to treatment. We describe clinical features, response to treatment and outcome of patients diagnosed with inborn errors of aminergic neurotransmitters in our center. Methods : A retrospective descriptive study and a prospective follow-up of 17 patients. Review of clinical records. Results: 17 patients. 16/17 exhibit DRD. 12/16 women. On 9/16 the average was 5 years age at onset and 9.5 years at diagnosis. In all patients the initial symptom was gait disturbance with diurnal fluctuation, lower limb (8/9) and upper limb (8/9) dystonia, trunk dystonia (3/9), tremor (3/9). Adult relatives (7/16) begin symptoms between 20 and 40 years: focal dystonia , parkinsonism. The mode of inheritance was autosomal dominant. The phenylalanine test was guiding. Diagnosis is confirmed with measurement of CSF levels of NT: low concentrations of neopterins, biopterins and 5HIAA HVA suggest deficiency of GTPCH1. Positive genetic study in 2 families. The response to levodopa treatment was satisfactory. One patient (1/17) shows a deficit of L-Dopa decarboxylase with severe global psychomotor retardation, fever, hypotonia, epilepsy, dystonia, and fatal outcome. Conclusions : In our series predominates DRD, with clinical features and response to treatment classically described. Early diagnosis allows prompt treatment with improvement of symptoms and favorable course.