Decelerated rate of dendrite outgrowth from dopaminergic neurons in primary cultures from brains of hypoxanthine phosphoribosyltransferase-deficient knockout mice.

Lesch-Nyhan syndrome (LNS), caused by the complete deficiency of hypoxanthine phosphoribosyltransferase (HPRT), is characterized by a neurological deficit, the etiology of which is still unclear. Evidence has accumulated indicating that it reflects dopamine deficiency associated with defective arborization of dopaminergic dendrites. We monitored the differentiation in vitro of dopaminergic neurons, cultured from HPRT-deficient knockout mice. The HPRT-deficient dopaminergic neurons exhibited a decelerated rate of outgrowth of dendrites in comparison to that of control neurons resulting, after 8 days in culture, in 32% smaller average total length of dendrites per neuron (P<0.025). The results suggest that the abnormal dendrite outgrowth in LNS reflects a defective developmental process.