What is Rett syndrome?
Rett syndrome is a developmental nervous system disorder. The disorder almost exclusively affects girls. Rett syndrome is classified as classic or atypical. The classification depends on the symptoms one has and the gene mutation. Some common characteristics and symptoms of Rett syndrome are involuntary hand movements, skill regression in communication and motor skill such as important hand movements, feeding difficulties, seizures and slow head growth or smaller overall head size throughout the years.
Classic Rett syndrome
Classic Rett syndrome is the most common form of Rett syndrome. It affects about 80% to 85% of those diagnosed with Rett syndrome. Symptoms of the disorder usually present themselves as early as 6 to 18 months of age. Rett syndrome progresses in four stages.
A description of the four phases and symptoms are listed in order of occurrence as follows.
- Early onset phase: This phase begins around 6 to 18 months of age and lasts for several months. At this time, the child may make less eye contact, show less interest in toys and interaction with parents and others, and have delayed head growth.
- Rapid destructive phase: This phase occurs between the ages of 1 and 4. During this time, the child loses their previous speech abilities, lacks the ability to use their hands, may lose muscle tone, may have repetitive hand movements such as constantly putting their hands in their mouth or clapping, and may have difficulties breathing. The child may also have difficulties crawling or walking, trouble sleeping, and be irritable.
- Plateau phase: This stage lasts for years. During this time, symptoms stabilize. Individuals may even regain some of their lost communication skills. However, symptoms such as repetitive hand movements, seizures, and intellectual disabilities remain.
- Late motor deterioration phase: This stage has a broad range at which it can occur. It occurs after the previous stage ends but can happen anywhere from the ages of 5 to 25. During this phase, muscles weaken, making it difficult to walk.
Atypical Rett syndrome
Atypical Rett syndrome is the more severe type of the syndrome, affecting about 15% to 20% of all cases. There are 5 different types of atypical Rett syndrome.
- Early-onset seizure type: Those affected normally have seizures before 6 months of age.
- Preserved speech type: Those affected show the same symptoms as classic Rett syndrome, but some of their speech and motor skills resurface. Obesity, aggression, and behaviors that resemble the behaviors of those with autism are common.
- Congenital type: This type is the most severe type of the atypical forms of Rett syndrome. During the first 3 months of life, patients show symptoms such as loss of muscle tone and developmental delays. Those affected also often have facial deformities.
- Late onset type: With this form of the disease, progression occurs later than the classic form of the disease. Symptoms begin to present themselves in early childhood. Those affected may maintain the use of their hands. Stereotypic hand movements are also common. This includes repetitive movements such as picking, waving, or squeezing. This is a milder form of the disease.
- Late childhood regression type: With this form of Rett syndrome, regression of motor and speech skills occurs later and at a gradual pace rather than suddenly and rapidly.