Rett syndrome

Rett syndrome is a neurodevelopmenal disorder that affects girls almost exclusively. It is characterized by normal early growth and development followed by a slowing of development, loss of purposeful use of the hands, distinctive hand movements, slowed brain and head growth, problems with walking, seizures, and intellectual disability.

Children with Rett syndrome often exhibit autistic-like behaviors in the early stages. Other symptoms may include walking on the toes, sleep problems, a wide-based gait, teeth grinding and difficulty chewing, slowed growth, seizures, cognitive disabilities, and breathing difficulties while awake such as hyperventilation, apnea (breath holding), and air swallowing.

Development

Development is typically normal until 6–18 months, when language and motor milestones regress, purposeful hand use is lost, and acquired deceleration in the rate of head growth (resulting in microcephaly in some) is seen. Hand stereotypes are typical, and breathing irregularities such as hyperventilation, breathholding, or sighing are seen in many. Early on, autistic-like behavior may be seen. The infant with Rett syndrome often avoids detection until 6–18 months, owing to a relatively normal appearance and some developmental progress. However, closer scrutiny reveals disturbance of the normal spontaneous limb and body movements that are thought to be regulated in the brainstem. The brief period of developmental progress is followed by stagnation and regression of previously acquired skills. During regression, some features are similar to those of autism.  

Symptoms of Rett syndrome

Beginning between 3 months and 3 years of age, most children with Rett syndrome start to show some of the following symptoms:

Loss of purposeful hand movements, such as grasping with fingers, reaching for things, or touching things on purpose

Loss of speech

Balance and coordination problems, including losing the ability to walk in many cases

Stereotypic hand movements, such as hand wringing

Breathing problems, such as hyperventilation and breath holding, or apnea when awake

Anxiety and social-behavioral problems

Intellectual and developmental disabilities

Usual course of Rett syndrome

Early Onset Phase – Development stalls or stops.

Rapid Destructive Phase – The child loses skills (regresses) quickly.  Purposeful hand movements and speech are usually the first skills lost.

Plateau Phase – Regression slows, and other problems may seem to lessen or improve. Most people with Rett syndrome spend most of their lives in stage 3.

Late Motor Deterioration Phase – Individuals may become stiff or lose muscle tone; some may become immobile.

Causes

Nearly all cases of Rett syndrome are caused by a mutation in the methyl CpG binding protein 2, or MECP2(pronounced meck-pea-two) gene. Scientists identified the gene — which is believed to control the functions of many other genes — in 1999.  The MECP2 gene contains instructions for the synthesis of a protein called methyl cytosine binding protein 2 (MeCP2), which is needed for brain development and acts as one of the many biochemical switches that can either increase gene expression tell other genes when to turn off and stop producing their own unique proteins.  Because the MECP2 gene does not function properly in individuals with Rett syndrome, insufficient amounts or structurally abnormal forms of the protein are produced and can cause other genes to be abnormally expressed.

Not everyone who has an MECP2 mutation has Rett syndrome.  Scientists have identified mutations in the CDKL5 andFOXG1 genes in individuals who have atypical or congenital Rett syndrome, but they are still learning how those mutations work.  Scientists believe the remaining cases may be caused by partial gene deletions, mutations in other parts of the gene, or additional genes that have not yet been identified, and they continue to look for other causes.

Treatment for Rett syndrome

There is currently no cure for Rett syndrome. However, girls can be treated for some of the problems associated with the condition. These treatments generally aim to slow the loss of abilities, improve or preserve movement, and encourage communication and social contact.

People with Rett syndrome often benefit from a team approach to care, in which many kinds of health care providers play a role, along with family members.  Members of this team may include:

Physical therapists, who can help patients improve or maintain mobility and balance and reduce misshapen back and limbs

Occupational therapists, who can help patients improve or maintain use of 

their hands and reduce stereotypic hand movements.

Speech-language therapists, who can help patients use non-verbal ways of communication and improve social interaction.

Other options, such as medication (such as for constipation or heart problems) or surgery (to correct spine curvature or correct heart defects) are also effective for treating some of the symptoms of Rett syndrome.

Is Rett syndrome inherited?

Although Rett syndrome is a genetic disorder, less than 1 percent of recorded cases are inherited or passed from one generation to the next. Most cases are spontaneous, which means the mutation occurs randomly. However, in some families of individuals affected by Rett syndrome, there are other female family members who have a mutation of theirMECP2 gene but do not show clinical symptoms.  These females are known as “asymptomatic female carriers.”