By 2. Low Muscle Tone, Jerky Movements
Children with Rett syndrome often show low muscle tone early in life. This means the muscles feel soft and weak, which can make it hard to hold the head up, sit straight, or keep balance. As the condition progresses, movement can become uneven and sudden.
Jerky movements may appear in the arms, legs, or upper body. A child may shake, twitch, or make quick motions without control. These movements can interrupt smooth actions like reaching for a toy or turning the body.
They may happen more often during stress, excitement, or tiredness. Walking patterns can also change. Gait may look stiff or unsteady, with short steps or toe walking. Caregivers may also notice that the child tires easily during physical activity.
3. Delayed Speech
Delayed speech is a common early sign of Rett syndrome. Many children produce typical speech sounds during the first months of life, which can make early development seem normal. Over time, speech development may slow, stop, or move backward.
A child may use fewer words than expected for their age, never develop clear spoken words, or lose words they once used. Caregivers may notice that the child speaks less during play or daily routines and stops using sounds to get attention or express needs. Signs can include limited babbling after infancy and loss of simple words such as “mama” or “bye.”
Other signs include reduced use of sounds to communicate and difficulty copying sounds or words. Speech delay often becomes more noticeable between the early toddler years and preschool age. Even with less speech, many children still connect with others using eye contact, facial expressions, or body movements.
4. Regression
Regression refers to a clear loss of skills that a child had already gained. In Rett syndrome, this change often begins after a short period of typical growth. Many children appear to develop as expected during the first several months of life, which can make the shift especially confusing for caregivers.
During regression, a child may stop using words they once said and show less interest in social play. They may respond less to people around them, with reduced eye contact and fading shared attention. These social and communication changes are often among the earliest signs noticed during this stage.
Hand skills frequently change as well. A child may stop reaching for toys or feeding themselves. Purposeful hand movements can be replaced by repeated actions such as clapping, rubbing, or twisting the hands, which become more noticeable over time. Movement may also become more difficult. Sitting, crawling, or walking can appear less steady than before. Balance problems and stiff movements may develop and gradually increase, affecting how the child moves through daily activities.
5. Slow Growth
Slow growth often appears early in children with Rett syndrome. During the first months of life, growth may seem typical, which can delay concern. Over time, however, the rate of growth slows, especially in head size, height, and weight.
Head growth is often the first area affected. Healthcare providers may notice that the head does not increase at the expected rate during routine checkups. This change can signal slowed brain growth and may appear before other clear signs of the condition.
Body growth also slows as the child gets older. Weight gain may remain low even with regular feeding, and height may increase more slowly compared with children of the same age.
6. Loss of Normal Communication
Loss of normal communication is a key sign of Rett syndrome. Many children show typical speech and social sounds during early infancy, which can make early development appear expected. Over time, these skills fade, and children may stop using words they once knew.
Speech loss often begins between the early toddler years and preschool age. It may happen gradually or over a shorter period. A child may stop babbling, speaking single words, or responding to their name. They may also struggle to use eye contact, facial expressions, or gestures to share needs, making daily interactions more difficult for caregivers and teachers.
Even with speech loss, some understanding may remain. Many children still respond to familiar voices, sounds, or routines and show awareness through eye gaze, body movement, or changes in mood.
7. Irregular Heartbeat/Seizures
Some people with Rett syndrome develop an irregular heartbeat. The heart may beat too fast, too slow, or unevenly, and these changes can come and go. Early on, they may not cause clear symptoms. Caregivers may notice brief pauses in breathing, sudden fatigue, or fainting, especially during rest or sleep.
Changes in heart rhythm raise safety concerns because they increase the risk of sudden health events. Seizures are also common in Rett syndrome and often begin in childhood. Some seizures appear as staring spells, while others involve stiff or jerking movements.
8. Curvature of the Spine
Curvature of the spine often appears as Rett syndrome progresses. This change is commonly known as scoliosis, which means the spine curves to the side instead of remaining straight. This sign usually develops during childhood or early teen years and can worsen as muscle control and balance decline.
Limited movement and low muscle tone can place uneven pressure on the spine, which contributes to the curvature. As the spine begins to curve, posture and comfort may be affected. Some children sit or stand with one shoulder higher than the other, while others lean to one side when sitting, even when supported. As the curve becomes more pronounced, it can interfere with sitting balance and breathing. A severe spinal curve can reduce chest space, making breathing more difficult during rest or illness.
9. Stage 1
Stage 1 of Rett syndrome often begins between 6 and 18 months of age. During this period, a child may appear generally healthy, but subtle changes begin to emerge. A child may sit, crawl, or walk later than expected.
Eye contact may decrease, and interest in toys or people can fade. Speech and sound use may also slow, with some children babbling less or using fewer sounds. They may seem quieter or less responsive during play.
A child may grip toys less often or stop using their hands with clear purpose. Repetitive hand movements may begin during this stage, although they are often mild and easy to overlook. The child may seem stiff or less steady, and balance may not develop as expected.
Sleep may become shorter or more disrupted, and feeding may take longer or feel more difficult. Stage 1 typically progresses slowly. Over time, many children move into later stages as symptoms become more apparent and easier to recognize.
10. Stage 2
Stage 2 of Rett syndrome often begins between one and four years of age. This stage marks a noticeable shift following a period of typical early growth. Skills that once appeared stable begin to fade, and changes become more obvious to caregivers.
Loss of communication is common during this stage, with children often losing words they had learned. Hand use often declines as well, making purposeful actions such as grasping more difficult. Repetitive hand movements, including wringing or tapping, may begin and continue throughout the day.
Walking may appear unsteady, or a child may walk less than before. Muscle control can weaken, which affects posture, coordination, and overall stability. A child may seem less interested in people or surroundings.
Crying, irritability, and sleep problems may increase, which can be confusing for caregivers. Breathing patterns can also change, with some children showing episodes of rapid breathing or breath holding while awake.
11. Stage 3
Stage 3 of Rett syndrome often begins in early childhood and extends into the school years. This stage is commonly called the plateau stage because some changes slow down compared with earlier stages. During Stage 3, behavior may improve slightly.
Many children show less crying and fewer sudden mood changes. Attention and eye contact can increase, which may support social connections. However, spoken language does not return, and communication remains limited. Some children use eye gaze, sounds, or simple tools to share needs and rely on caregivers to interpret these signals. Movement challenges continue and may become more noticeable. Walking often appears stiff or unsteady, and balance remains limited.
Hand use stays restricted, with repetitive hand movements occurring frequently. Breathing patterns may still be uneven during wakefulness. Sleep problems can persist and affect daytime energy and alertness. Seizures may occur during this stage and often require ongoing management with antiseizure medications. Learning remains very difficult, although some level of understanding may still be present.
12. Stage 4
Stage 4 of Rett syndrome often begins in late childhood or the teen years and can last for many years. During this stage, symptoms tend to level out rather than worsen rapidly, though movement problems usually become more pronounced. Many individuals need assistance to walk, and some stop walking over time.
Muscle stiffness and poor balance raise the risk of falls. The curvature of the spine may continue to progress and affect posture. Repetitive hand movements, such as wringing or clapping, typically persist, while purposeful hand use and fine motor skills remain limited. Speech does not return during this stage, but awareness often improves.
Many individuals show better eye contact and greater interest in people around them. Nonverbal communication, especially eye gaze, becomes an important way to interact and express needs. Seizures may continue but often become easier to manage with ongoing care. Breathing problems can still occur, particularly during stress or sleep.
13. Variants
Rett syndrome includes several variants. The classic form is the most common. Children typically grow as expected during the first several months of life, followed by a loss of speech and hand skills. Repetitive hand movements, slowed growth, and breathing changes often develop afterward. Many girls with Rett syndrome fit this pattern.
Some children show symptoms much earlier than usual. This early-onset variant begins in the first months of life. Development slows quickly, muscle control remains weak, and seizures may begin at a young age. Daily functioning is often more limited from the start.
Another variant follows a milder course. Speech and hand use decline less, and some skills are retained. Walking may remain stable for a longer time, allowing greater independence with daily tasks compared with other forms. A rare and severe form mainly affects boys. Symptoms begin at birth with significant brain involvement. Breathing, feeding, and movement remain very limited, and survival beyond infancy is uncommon.
14. Early Death
Early death can occur in people with Rett syndrome due to health complications, although many individuals live into adulthood. Breathing problems may lead to long pauses or irregular breathing patterns, especially during sleep.
Seizures can become severe or difficult to control. Some individuals also develop heart rhythm changes, which increase the risk of sudden health events. Sudden death can sometimes occur without warning.
These sudden events are often linked to problems with heart rhythm and breathing control. Illness, fever, or physical strain can worsen symptoms and increase risk. Limited movement can also raise the chance of chest infections, which further affects overall health.
