Low CSF HVA levels in the Rett syndrome: a reflection of restricted synapse formation?

The concentration of neurotransmitter metabolites in the CSF was determined in 10 girls with the Rett syndrome (RS) (age range 5.8-17.2) and in 14 control children (age range 4.5-16.7) treated for acute leukemia without signs of CNS involvement. Homovanillic acid concentration decreased with age in both groups. The decrease was less steep in RS compared to controls, with lower concentrations in young girls and normal concentrations at 15 years of age. 5-hydroxyindoleacetic acid decreased proportionally in both groups. It is suggested that the low concentration of HVA in young girls reflect deficient multiplication of catecholaminergic synapsis.