Brief Description

A genetic disorder of neurodevelopmental arrest rather than a progressive process that affects females almost exclusively. Characterized by  normal early growth and development followed by slowing of development.

Defect

PROTEIN that regulates gene expression.

Incidence

Wide variations in various countries.

U.S.      1:23,000

Japan   1:45,000

Types/Forms 

ATYPICAL – begins early (soon after birth or late beyond 18 months of age) speech and hand    skills problems are mild

CLASSICAL  –  meets diagnostic criteria

PROVISIONAL  –  some symptoms appears between ages 1-3

Manifestation

STAGE I  –  (typically in children 6-18 months)  gross motor developmental delay, loss of eye contact, deceleration in head growth, and weight growth, height growth, hypotonia and hand wringing.   Infants with Rett may appear placid and calm compare to healthy infants.

STAGE II  –  (typically from ages 1-4 years)  autistic like behavior, loss of social interaction and communication skills with no oral language.  Episodes of hyperventilation  or breath holding. Seizure, irritability, midline handwringing, clapping, hand washing or hand to mouth movements.  Slow head growth usually noticed during this stage.

STAGE III –  (typically in children ages 2-10) Findings may include hand stereotypies, rigidity, hyperventilation, breath holding, bruxism, involuntary tongue movements, poor weight gain, and scoliosis.

STAGE IV –   Late motor deterioration (typically in individuals >10 y) Findings may include dystonia, rigidity, muscle wasting, quadriparesis, scoliosis or kyphoscoliosis, loss of ambulation, growth retardation, hyperventilation, and seizures.  Improvements may be observed in frequency and intensity of hand movements.  Eye contact continues to be preserved and may be the only avenue by which emotions and needs can be communicated.

Diagnosis

Diagnosis of classic Rett syndrome requires that patients meet certain necessary (main), supportive, and exclusionary characteristics as outlined in Diagnostic criteria.

Examples of main diagnostic criteria or symptoms include partial or complete loss of acquired purposeful hand skills, partial or complete loss of acquired spoken language, repetitive hand movements (such has hand wringing or squeezing, clapping or rubbing), and gait abnormalities, including toe-walking or an unsteady, wide-based, stiff-legged walk.

Females who meet the clinical diagnostic criteria should undergo genetic testing.

Prognosis

Life expectancies are not well studied, although survival at least until the mid-20s is likely. The average life expectancy of a girl with Rett syndrome may be mid-40s. Death may be sudden and often is secondary to pneumonia. Risk factors include seizures, loss of mobility, and difficulties with swallowing.

Treatment

Treatment for the disorder is symptomatic — focusing on the management of symptoms — and supportive, requiring a multidisciplinary approach.  Medication may be needed for breathing irregularities and motor difficulties, and anticonvulsant drugs may be used to control seizures.  There should be regular monitoring for scoliosis and possible heart abnormalities.  Occupational therapy can help children develop skills needed for performing self-directed activities (such as dressing, feeding, and practicing arts and crafts), while physical therapy and hydrotherapy may prolong mobility.  Some children may require special equipment and aids such as braces to arrest scoliosis, splints to modify hand movements, and nutritional programs to help them maintain adequate weight

References