Signs and symptoms
Some children with Rett syndrome are affected more severely than others. Also, the age at which symptoms first appear varies from child to child.
A child with Rett syndrome may not have every symptom listed below, and their symptoms can change as they get older.
Rett syndrome is described in 4 stages, although symptoms will often overlap between each stage. The main features of each stage are described below.
Stage 1: early signs
At first, the child will appear to develop and grow normally for at least 6 months, although (especially with hindsight) there may be subtle signs of Rett syndrome before the child is recognised as having a problem.
Stage 1 is sometimes described as "stagnation" because the child's development slows down or stops altogether. Symptoms include:
- low muscle tone (hypotonia)
- difficulty feeding
- unusual, repetitive hand movements or jerky limb movements
- delay with development of speech
- mobility problems, such as problems sitting, crawling and walking
- lack of interest in toys
These symptoms typically begin during the period from 6 to 18 months of life and often last for several months, although they can persist for a year or more.
Stage 1 can often go unnoticed by the child's parents and by healthcare professionals because the changes occur gradually and may be subtle.
Stage 2: regression
During stage 2, known as "regression" or the "rapid destructive stage", the child starts to lose some of their abilities. This stage usually begins between the ages of 1 and 4 and may last for any time from 2 months to more than 2 years.
The child will gradually or suddenly start to develop severe problems with communication and language, memory, hand use, mobility, co-ordination and other brain functions. Some of the characteristics and behaviours are similar to those of autism spectrum disorder.
Signs at this stage include:
- loss of the ability to use the hands purposefully – repetitive hand movements are often difficult to control and include wringing, washing, clapping or tapping
- periods of distress, irritability and sometimes screaming for no obvious reason
- social withdrawal – a loss of interest in people and avoidance of eye contact
- unsteadiness and awkwardness when walking
- problems sleeping
- slowing of head growth
- difficulty eating, chewing or swallowing, and sometimes constipation that may cause tummy aches
Later on during regression, the child may experience periods of rapid breathing (hyperventilation) or slow breathing, including breath-holding. They may also swallow air which can lead to abdominal bloating.
Stage 3: plateau
Stage 3 of Rett syndrome can begin as early as 2 years of age or as late as 10 years of age. It often lasts for many years, with many girls remaining in this stage for most of their lives.
During stage 3, some of the problems that occurred at stage 2 may get better – for example, there may be improvements in behaviour, with less irritability and crying.
The child may become more interested in people and their surroundings, and there may be improvements in alertness, attention span and communication. Their walking ability may also improve (or they may learn to walk, if they were previously unable to do so).
On the downside, problems that can arise during stage 3 include:
- seizures, which become more common
- irregular breathing patterns may get worse – for example, shallow breathing followed by rapid, deep breathing, or breath holding
- teeth grinding
- some children may develop heart rhythm abnormalities (arrhythmias)
Gaining and maintaining weight can also be difficult to achieve.
Stage 4: deterioration in movement
Stage 4 can last for years or even decades. The main symptoms at this stage are:
- development of a spinal curve (the spine bending to the left or right side), known as scoliosis
- muscle weakness and spasticity (abnormal stiffness, particularly in the legs)
- losing the ability to walk
Communication, language skills and brain function don't tend to get any worse during stage 4. The repetitive hand movements may decrease and eye gaze usually improves.
Seizures also usually become less of a problem during adolescence and early adult life, although they will often be a lifelong problem to manage.