Rett syndrome (RTT) is a rare neuropsychiatric condition associated to mutations in the gene coding for the methyl-CpG- binding protein 2 (MECP2). It is primarily observed in girls and affects individuals globally. The understanding of the neurobiology of RTT and patient management has been improved by studies that describe the demographic and clinical presentation of patients with RTT. However, in Ireland, there is a scarcity of data regarding patients with RTT, which impedes the ability to fully characterize the Irish RTT population. Together with the Rett syndrome association of Ireland (RSAI), we prepared a questionnaire to determine the characteristics of RTT patients in Ireland. Twenty families participated to the study to date, providing information about demographics, genetics, familial history, clinical features, and regression. The main finding of this study is the limited number of genetic tests conducted to support the clinical diagnosis of RTT. The results shows that Irish patients with RTT have comparable presentation with respect to patients in other countries, however, they had a better response to anti-epileptic drugs and fewer skeletal deformities were reported. Nonetheless, seizures, involuntary movements and regression were more frequently observed in Irish patients. Despite the limited sample size, this study is the first to characterise the RTT population in Ireland and highlights the importance of genetic testing for patients with RTT in order to sharpen the characterization of the phenotype and increase the visibility of Irish patients in the international RTT community.