Rett Syndrome is a childhood neurodevelopment disorder. This is condition that almost exclusively occurs in females. It happens about once in every 10,000-15,000 live female births, and it is seen in all racial and ethnic groups worldwide. In most cases, the mutation that causes Rett Syndrome arises spontaneously. There also seem to be some clusters within families and certain geographic regions like Norway, Sweden and Northern Italy.
The gene associated with Rett Syndrome is on the x-chromosome. This gene contains instructions for a protein that regulate the manufacture of various other proteins. It causes these proteins to be produced incorrectly and damages the maturing brain.
Although Rett Syndrome is a genetic disorder, less than 1% of recorded cases are inherited or passed from one generation to the next. Most cases are sporadic and occur randomly and this is not inherited.
Females have two x chromosomes, so even when one has this significant mutation, the other x chromosome provides enough normal protein for the child to survive. In males, they do not have the second x chromosome to compensate for the problem, so the mutation is lethal, leading to miscarriage, stillbirth or very early death.
In Rett Syndrome, The age of onset and severity of symptoms varies from child to child. The child has normal early development, usually 6 to 18 months, but then develops loss of use of the hands, distinctive hand movements, slowed brain and head growth, gait abnormalities, seizures and mental retardation. Most often, the first physical symptom to appear is hypotonia, which is the loss of muscle tone. The child loses purposeful use of her hands and the ability to speak. Some other early symptoms are problems crawling or walking and avoidance of eye contact.
When the child loses the use of her hands, compulsive hand movements such as wringing and washing motions, hand clasping and hand mouthing movements take over and are almost constant while awake.
The onset of this period of regression is often sudden. Apraxia–the inability to perform motor functions–is the most disabling feature of Rett Syndrome and interferes with every body movement, including eye gaze and speech.
The early symptoms of Rett Syndrome is much like early autistic behaviors and is often misdiagnosed as autism or cerebral palsy. Some other symptoms of Rett’s may include toe walking, sleep problems, wide-based gait, teeth grinding, difficult chewing, slowed growth, seizures, cognitive disabilities, breathing difficulties while awake, apnea (breath holding) and air swallowing.
There are four stages of Rett Syndrome:
Stage I. Early Onset Stage. This stage usually begins sometime between 6 and 18 months and is often overlooked as symptoms can be vague. The infant may begin to show less eye contact, have reduced interest in toys, have delays in gross motor skills such as sitting or crawling. Hand-wringing and decreasing head growth may occur but not enough to draw attention. This first stage usually lasts a few months, but can persist for more than a year.
Stage II. Rapid Destructive Stage. This stage usually begins between the ages of 1 and 4 and lasts for weeks or months. This stage can have either a rapid or gradual onset as purposeful hand skills and spoken language are lost. The characteristic hand motions begin to emerge. These movements persist while the child is awake, but disappear during sleep. Breathing irregularities such as episodes of apnea and hyperventilation may occur, but breathing is usually normal during sleep. Some autistic-like symptoms occur such as loss of social interaction and communication. Also irritability and sleep irregularities may be seen. Gait is unsteady and difficult. Slowing of head growth is usually seen during this stage.
Stage III. Plateau or Pseudo-Stationary Stage. This stage usually begins between the ages of 2 and 10 and can last for years. Apraxcia, motor problems and seizures are prominent during this stage. There may, however, be improvement in behavior, with less irritability, crying and autistic-like behaviors. Girls in stage III. may show more interest in their surroundings and her alertness, attention span and communication skills may improve. Many girls remain in this stage for most of their lives.
Stage IV. Late Motor Deterioration Stage.
This is the last stage and can last for years or decades and is characterized by reduced mobility. Muscle weakness, rigidity and stiffness, spasticity, dystonia (increased muscle tone with abnormal posturing of extremity or trunk) and curvature of the spine are other prominent features. Girls who were previously able to walk may stop walking. There is usually no decline in cognition, communication or hand skills in stage IV. Repetitive hand movements may decrease and eye gaze usually improves.
Retts Syndrome is diagnosed by physicians observing signs and symptoms during the child’s early growth and development. A recent genetic test to confirm the clinical diagnosis of this order is being used and is able to confirm a clinical diagnosis in up to 80% of all cases. Some children do not fulfill the diagnostic criteria for syndrome. These girls are described as having “atypical” or “variant” Rett Syndrome. Atypical cases account for about 15% of the total diagnosed cases.
There is no cure for Rett Syndrome. Treatment is symptomatic (focusing on the management of symptoms). Medications may be needed for breathing irregularities and motor difficulties and antiepileptic drugs may be used to control seizures. Some children may require special equipment, braces, splints, nutritional programs, and special academic, social, vocational and support services may also be required.
Most females with Rett Syndrome continue to live well into middle age and beyond, but not enough women have been studied to make reliable estimates about life expectancy beyond the age of 40.