The case-histories of 7 girls and 1 woman, 2 to 25 years of age, are reported from the Clinical Genetics and Child Developmental Center, Department of Maternal and Child Health, Dartmouth Medical School, Hanover, NH. Diagnosis was made after 5 years of age in 4 of the patients when the characteristic hand wringing, hand washing movements were first noted. In addition to these stereotypic hand behaviors, other clinical features included loss of hand function, hyperventilation, bruxism, irritability or self-injury, sleep disturbance, strabismus, seizures, scoliosis, ataxia, and hypotonia in infancy. Head growth deceleration, short stature and retarded rate of growth occurred in almost all cases. Three were small for gestational age at birth and experienced neonatal feeding problems. Previous diagnoses included Angelman syndrome, encephalopathy, and encephalitis, and in 1 case the syndrome appeared to develop as a reaction to pertussis vaccine. Treatment was symptomatic and supportive. Music and motion such as rocking or riding in a car had a calming effect, particularly when screaming attacks and sleep disturbances were troublesome. The absence of a “biological marker” for Rett syndrome makes diagnosis difficult and may lead to confusion with other defined neurodegenerative disorders, such as leukodystrophies, spinocerebellar heredoataxias, neuronal ceroid lipofuscinosis, and ornithine transcarbamylase deficiency. 
COMMENT. The diagnostic criteria for Rett syndrome proposed by the International Rett Syndrome Association (see Ped Neur Briefs 1988;2: 29) in April 1988 were separated into 1) necessary, 2) supportive, and 3) exclusion categories. Normal development through the first 6 or 18 months was regarded as a necessary criterion and intrauterine growth retardation and microcephaly at birth were thought to exclude the diagnosis. By these criteria, 4 of the 8 cases described here would not be accepted as examples of Rett syndrome or, alternatively, a “forme fruste” atypical variety of the syndrome might be recognized. Even the female sex is no longer considered a necessary diagnostic criterion and a less restrictive symptom complex is proposed by some. The occurrence of a similar history and syndrome is boys is not uncommon. A plethora of publications on Rett syndrome has appeared in the last 12 months but none has uncovered a specific cause. The present authors note that pertussis vaccine was considered causative in 7 of 19 girls with Rett syndrome reported from Scotland (Br Med J 1985; 219:579), and the onset of regression heralded by inconsolable screaming attacks had followed recent pertussis immunization in 1 patient in their series of 8.