What is Rett Syndrome?
Mutations in the MECP2 (pronounced as meck-pee 2) gene cause a rare developmental disorder known as Rett Syndrome. It can mimic symptoms of autism spectrum disorders or cerebral palsy. The MECP2 gene is found on the X chromosome, explaining why the disorder is most commonly seen in girls. Rett Syndrome stages follow a characteristic although not absolute path in terms of progressive symptoms. The stages themselves are characteristic in terms of symptoms, but the age at which each stage begins or ends can vary from one child to the next. Likewise, the duration of each stage varies from a few weeks to decades.
Rett Syndrome Stage I
According to the National Institute of Neurological Disorders and Stroke (NINDS,) Rett Syndrome stages follow a pattern, beginning with the early onset, progressing to the rapid destructive stage, the plateau, and the late motor deterioration stage. In the early onset stage, or Stage I, symptoms are easy to overlook. Stage I lasts only a few months.
During early onset, development slows, interest in toys or playtime diminishes, and eye contact decreases. Stage I develops between the ages of 6-18 months. Some physical symptoms such as delays in gross motor development, slowing of head growth, or the characteristic hand-wringing may begin. However, these symptoms, if present at all, are extremely subtle and easy to miss.
The rapid destructive stage, or Stage II, begins after the first year but before the age of four. In terms of Rett Syndrome stages, Stage II’s duration can be as short as a few weeks or as long as several months. During this stage, symptoms are far more pronounced and easier to identify as outside the range of normal development. Behavior problems such as frequent irritability may also present.
In Stage II, the child loses language skills previously developed and also shows signs of characteristic behaviors. Hand-wringing, the loss of intentional and purposeful hand use, and the beginnings of breathing difficulties begin. It is during this stage that lack of or slowing of head growth is most notable. In some girls, voluntary communication and social reciprocity slows, explaining why some girls are misdiagnosed on the autism spectrum during this stage.
Onset of the plateau stage, also known as Stage III or the pseudo-stationary stage, begins between the ages of 2-10. It is during this time that most characteristic symptoms present. They include seizures, motor planning problems, and increased breathing difficulties. As with Stage II, many of these issues seem to calm while the child is sleeping. Frequent seizures, hand-wringing, clapping, and periodic occurrences of apnea or other breathing problems during waking hours are common.
While certain symptoms increase in intensity during this stage, other symptoms improve. For example, behavioral problems like irritability decrease. Her awareness and interaction with the world around her may improve, as do communication skills in some patients. Stage III lasts for years, with some patients never progressing to Stage IV.
During the final of Rett Syndrome stages, the late motor deterioration stage or Stage IV, physical challenges are often severe. While cognitive skills remain the same or show improvement, this stage is marked by limited physical mobility. Some girls may lose the ability to walk, develop scoliosis, or appear to develop abnormal postures in their extremities. In some cases, girls may continue to lose cognitive or communication skills, but this happens in only a small percentage of cases.
While the stages of Rett Syndrome are progressive, the disorder itself is not considered degenerative. Girls diagnosed with this disorder can achieve a reasonable life expectancy, although exact statistics are difficult to identify. There are few documented cases of women over 50 with Rett Syndrome. However, this may be due in part to the difficulty diagnosing women without complete developmental records from birth to present. According to the International Rett Syndrome Foundation, the survival rate of patients aged 25-40 is 69%.
References and Resources
The International Rett Syndrome Foundation: https://www.rettsyndrome.org/about-rett-syndrome/what-is-rett-syndrome-2.html
National Institute of Neurological Disorders and Stroke: https://www.ninds.nih.gov/disorders/rett/detail_rett.htm#164543277
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