It is now known that RS can occur in males, but is usually lethal, causing miscarriage, stillbirth or early death.

First described by Dr. Andreas Rett, RS received worldwide recognition following a paper by Dr. Bengt Hagberg and colleagues in 1983.

The child with RS usually shows an early period of apparently normal or near normal development until 6-18 months of life. A period of temporary stagnation or regression follows during which the child loses communication skills and purposeful use of the hands. Soon, stereotyped hand movements, gait disturbances, and slowing of the rate of head growth become apparent.

Other problems may include seizures and disorganized breathing patterns which occur when awake.

Apraxia (dyspraxia), the inability to program the body to perform motor movements, is the most fundamental and severely handicapping aspect of RS. It can interfere with every body movement, including eye gaze and speech, making it difficult for the girl with RS to do what she wants to do.

Due to apraxia and lack of verbal communication skills, an accurate assessment of intelligence is difficult. Most traditional testing methods require use of the hands and/or speech, which may be impossible for the girl with RS.

RS is most often misdiagnosed as autism, cerebral palsy or non-specific developmental delay. While many health professionals may not be familiar with RS, it is a relatively frequent cause of neurological dysfunction in females. The prevalence rate in various countries is from 1:10,000 to 1:23,000 live female births.

Stages of Rett Syndrome

STAGE I
Early Onset
Age: 6 months to 1 ½ years
Duration: months

This stage is usually overlooked, as the symptoms of RS are just emerging and are somewhat vague.

The infant may show less eye contact and have reduced interest in toys.

She is often described as a "good" baby, calm and placid.

There may be delays in gross motor milestones. Non-specific hand wringing and decelerating head growth may be present.

STAGE II
Rapid Destructive
Age: 1 to 4 years
Duration: weeks to months

This stage can have a rapid onset or it can be more gradual as purposeful hand skills and spoken language are lost.

Stereotyped hand movements begin to emerge, and often include hand-to-mouth movements as the first expression. Movements are most often midline hand wringing or hand washing, and persist while the girl is awake but disappear during sleep. Other hand movements include hand clapping or tapping. Hands are sometimes clasped behind the back or held at the sides in a specific pose, with random touching, grasping and releasing.

Breathing irregularities may be noticed, and may include episodes of breath holding and hyperventilation associated with vacant spells. However, breathing is usually normal during sleep.

Some girls appear autistic-like with loss of social interaction and communication.

General irritability and sleep irregularity may be seen.

Periods of tremulousness may be obvious, especially when excited. Gait patterns are unsteady, and initiating motor movements can be difficult.

Slowing of head growth is usually noticed from 3 months - 4 years, when the girl's head circumference falls on a percentile chart (compared to children at the same age).

STAGE III
Plateau
Age: Pre-school to school years
Duration: years

This stage, from 2-10 years, follows the rapid destructive period.

Apraxia, motor problems and seizures are more prominent.

However, improvement is seen in behavior with less irritability and crying and less autistic features. She shows more interest in her surroundings, and her alertness, attention span and communication skills improve.

Many girls with RS remain in Stage III for most of their lifetime.

STAGE IV A (Previously ambulant)
STAGE IV B (Never ambulant)
Late Motor Deterioration
Age: When stage III ceases, 5-15-25-? years
Duration: up to decades

This stage usually begins after age 10, and is characterized by reduced mobility. Some girls stop walking, while others have never walked.

However, there is no decline in cognition, communication or hand skills. Repetitive hand movements may decrease.

Scoliosis is a prominent feature.

Eye gaze usually improves. Rigidity (stiffness) and dystonia (increased muscle tone with abnormal extremity or trunk positions) are characteristic.

Puberty begins at the expected age in most girls.