Six girls (five Saudis and one Sudanese) aged between 3.5 and 12 years demonstrated the classic features of Rett syndrome (RS), including developmental regression with dementia, loss of acquired speech and hand function, and stereotypic hand movements. Myoclonic seizures were observed in two of them. Electroencephalography showed diffuse slowing in three cases generalized epileptic discharges in one, and normal findings in two. Cranial computed tomography revealed normal findings, except in the 12-year-old girl who had mild bilateral frontal lobe atrophy. Except for mildly elevated blood ammonia in three patients, associated with slightly elevated blood lactate in two of them, results of neurometabolic screening tests were normal. There are, as yet, no laboratory markers pathognomonic for RS. Hence, adherence to current diagnostic criteria is essential. To prevent unnecessary and costly investigations, especially in developing countries, wider knowledge of the clinical features of the syndrome is warranted.