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 childwith Rett syndrome may not haveevery symptom listed below, and their symptoms can change as they get older.

Rett syndrome is described infour stages, although symptoms will often overlap between each stage. The main features of each stage are described below.

Stage one: early signs

At first, the child will appear to develop and grow normally for at least six months, although (especially with hindsight) there may be subtle signs of Rett syndrome before the child is recognized as having a problem.

Stage one 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 typicallybegin during the period from six to 18 months of life and often last for several months, although they can persist for a year or more.

Stage one can often go unnoticed by the child's parents and by healthcare professionals because the changes occur gradually and may be subtle.

Stage two: regression

During stage two, 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 one and four and may last forany time from two months to more than two 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 purposefullyrepetitive 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 ofhead 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 three:plateau

Stage three of Rett syndrome can begin as early as two 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 three, some of the problems that occurred at stage two may get better for example, there may beimprovements in behaviour, with less irritability andcrying.

The child may become more interested in people and their surroundings, and there may be improvements in alertness, attention span and communication. Theirwalking 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 three 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 toachieve.

Stage four: deterioration in movement

Stage four can last for years or even decades. The main symptoms at this stage are:

• development of a spinal curve (the spine bendingto 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 functiondon't tend to get any worse during stage four. The repetitive hand movementsmay 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.