Rett syndrome is a neurodevelopmental disorder that was first described by the pediatrician
Andreal Rett in 1966. This disorder is characterized by an initial period of normal childhood development, followed by a stereotypic pattern of developmental regression. It is considered to be part of the autism
spectrum of disease (termed the pervasive developmental disorders). Affected patients are almost exclusively female and they develop normally for a period of about 6 months before regression begins. The only feature of the disorder that has been shown to be present during this initial 6 month period is deceleration of head growth (beginning as early as 2 to 3 months of age), although this symptom is nonspecific and, in isolation, rarely prompts diagnosis of the disorder. After this initial period of relatively normal development, patients begin to regress developmentally. In some patient this regression occurs rapidly, but in most is occurs insidiously over weeks to months. In all patients with this syndrome, significant regression of fine motor, intellectual, and communicative abilities is seen by 12 to 18 months of age. Major specific features of this disease are loss of purposeful hand movement and development of stereotypic hand movements (periodic hand to mouth licking or repetitive grasping of the hair or clothing. Other features of Rett disorder are gait abnormalities, seizures, autistic behavioral features, and breathing abnormalities. Rett syndrome is caused by a mutation of the MECP2 gene on the X chromosome. It is believed that the disorder is almost exclusively found in girls because in boys (who only have one X chromosome and thus only one copy of the gene) mutation of the MECP2 gene is not compatible with life, so male fetuses with the mutation are inevitably spontaneously aborted. The disorder is quite uncommon, with an estimated prevalence of 1 case per 22,800 females aged 2 through 18 years of age. Although there are some physiologic abnormalities such as breathing and heart abnormalities that predispose patients to sudden death, survival into adulthood is typical. No specific therapy is available for the disease and affected patients often progress through life with profound cognitive, verbal, and motor deficits. Although no curative treatment is available for Rett disorder, special care is required for these patients and is often coordinated by a pediatrician or child psychiatrist
. It is important for any patient with this disease to maintain close follow up with a physician to be optimally treated and avoid the complications sometimes associated with this disease.