Rett syndrome

A neurodevelopmental disorder that affects girls almost exclusively.

Has many characteristic features including psychomotor retardation, impaired language development, hand stereotypies, gait dysfunction, and acquired microcephaly.

Epilepsy affects as many as 50%-90% of patients, which can often be refractory, requiring polytherapy nonpharmacologic management..

Affects approximately one in every 10,000 to 15,000 live female births and in all racial and ethnic groups worldwide.

Characterized by normal early growth and development followed by a slowing of development.

Patients develop loss of purposeful use of the hands, distinctive hand movements, slowed brain and head growth, problems with walking, seizures, and intellectual disability.

Course is variable, including the age of onset and the severity of symptoms.

In early infancy loss of muscle tone, difficulty feeding, and jerkiness in limb movements may be noted.

Gradually, mental and physical symptoms appear and the child loses purposeful use of her hands and the ability to speak.

Early symptoms may include problems crawling, walking and diminished eye contact.

Compulsive hand movements such as wringing and washing follows loss of hand function.

The inability to perform motor functions, apraxia, interferes with every body movement.

Often exhibit autistic-like behavior in the early stages.

Associated with difficult gait, walking on the toes, sleep problems, teeth grinding and difficulty chewing, slowed growth, seizures, cognitive disabilities, and breathing difficulties.

Four stages of Rett syndrome. Stage I, called early onset, typically begins between 6 and 18 months of age and is often overlooked because symptoms may be vague as it is associated subtle slowing of development.

Stage II, or the rapid destructive stage, usually begins between ages 1 and 4 and may last for weeks or months with loss of purposeful hand skills and spoken language.

Characteristic hand movements often begin during this stage.

Abnormal movements disappear during sleep and episodes of apnea and hyperventilation occur and also improve during sleep.

Autistic behavior occur in some patients.

This stage associated with slowing of head growth unsteady gait and motor movement abnormalities.

Stage III, or the plateau or pseudo-stationary stage, begins between ages 2 and 10 and can last for years associated with apraxia, motor problems, and seizures.

Improvement in behavior, autistic-like features and irritability.

\Patients may remain in this stage.

Stage IV, or the late motor deterioration stage, can last for years or decades and is associated with iumpaired mobility, scoliosis, muscle weakness, rigidity, spasticity, abnormal posturing of arms, legs, or trunk and progreesive impaired gait.

Caused by a mutation in the methyl CpG binding protein 2, or MECP2 gene, in most patients

MECP2 gene controls synthesis of methyl cytosine binding protein 2 (MeCP2), which is needed for brain development.

Remaining cases may be caused by partial gene deletions, mutations in other parts of the MECP2 gene, or additional genes, presently unidentified.

Less than 1 percent of cases are inherited and most cases are spontaneous.

In some families other female family members have a mutation of their MECP2 gene but do not show clinical symptoms, known as asymptomatic female carriers.

Prenatal testing is available for affected families, however the disorder occurs spontaneously in most affected individuals.

Sisters of girls with Rett syndrome who have an identified MECP2 mutation should be tested to determine if they are asymptomatic carriers.

MECP2 gene is on the X chromosome and only a portion of the cells in the nervous system will be effected by the gene abnormality and some brain cells express normal amounts of the protein: the severity of the disease in partly due to the percentage of their cells that express a normal copy of the MECP2 gene.

Male infants with a mutation of the MECP2 gene have no protection from the harmful effects of the disorder and die shortly after birth.

Diagnosis is by clinical signs and symptoms during the child’s early growth and development, and can be confirmed by genetic testing for the MECP2 gene mutation.

Treatment is symptomatic and supportive, requiring a multidisciplinary approach.

Patients may live well into middle age and beyond.

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