A translocation that disrupted the netrin G1 gene (NTNG1) was recently reported in a patient with an early seizure variant of Rett syndrome (RTT). The Netrin G1 protein (NTNG1) has an important in the developing central nervous system, particularly in axonal guidance, signalling and NMDA receptor function and awas a good candidate gene for RTT. We recruited 115 patients with RTT (females: 25 classic and 84 atypical; 6 males) but no mutation in the MECP2 gene. For those 52 patienta with epileptic seizure onset in the first 6 months of life. CDKL5 mutations were also excluded. We aimed to determine whether mutations in NTNG1 accounted for a sifgnificant subset of patients with RTT, particularly those with the early onset seizure variant and other atypical presentations. We sequenced the nine coding exons of NTNG1 and identified four sequence variants, none of which were likely to be pathogenic. Mutations in the NTNG1 function demands further investigation in relation to the central nervous system pathophysiology of the disorder. (c) 2006 Wiley-Liss, Inc.