What is rett syndrome?
Rett Syndrome (RTT) is a neurodevelopmental disorder characterized by onset in infancy and almost exclusively seen in girls. One of every 10,000 to 15,000 infant girls will develop Rett syndrome. It affects all racial and ethnic groups. (Case-Smith & O'Brien, 2010)
Although assumed to be a neurodegenerative disorder, it is categorized as a neurodevelopmental disorder. RTT affects the nervous system and leads to developmental reversals. RTT causes problems in brain function that are responsible for cognitive, sensory, emotional, motor and autonomic function. These can include learning, speech, sensory sensations, mood, movement, breathing, cardiac function, and even chewing, swallowing, and digestion. The severity of effects vary from one individual to another. (Case-Smith & O'Brien, 2010)
Rett syndrome has been most often misdiagnosed as autism, cerebral palsy or non-specific developmental delay.
Causes:
Most cases of Rett syndrome are caused by a mutation on the MeCP2 gene found on the X-chromosome. This gene is responsible for regulating protein production that promotes healthy brain development. When affected, it may under or over regulate the production and cause detrimental damage. (Who Does Rett Syndrome Affect?, n.d.)
It is almost only seen in girls due to the location of the mutation. Girls have to X-chromosomes whereas boys only have one. If a mutation is present in one X-chromosome of a female, the second normal function MeCP2 gene will attempt to compensate and allow the individual to survive. Contrarily, boys who have this mutation do not have the protective factors of a normal functioning gene on the second X-chromosome. Boys with a MeCP2 mutation often die before or shortly after birth. (Who Does Rett Syndrome Affect?, n.d.)
Rett Syndrome Inherited?
Typically the mutation is new having occurred during the replication/division of the chromosomes during formation. Thus most Rett syndromes occur randomly, rather than being inherited.
Progression of RTT
THE AGE WHEN RTT BEGINS AND THE SEVERITY of different symptoms may vary. The child with RTT is usually born healthy and shows an early period of apparently normal or near normal development until six to eighteen months of life, when there is a slowing down or stagnation of skills. (Hunter, 2007)
Children with Rett syndrome undergo four stages of the disease:
Stage 1: early signs and slow development
How is Rett Syndrome Diagnosed?
How Rett syndrome manifests itself and progresses varies from child to child. In most cases, the correct diagnosis can be made through a blood test(s) to identify the mutation of the MECP2 gene. But since the MECP2 mutation can also be found with other disorders, this finding alone is not enough to make a conclusive diagnosis of Rett syndrome. (Who Does Rett Syndrome Affect?, n.d.)
There are specific diagnostic criteria for typical/classical and for atypical/variant Rett syndrome. Both require that the child have had a period of regression in developmental skills followed by stabilization and/or improvements. (Who Does Rett Syndrome Affect?, n.d.)
A case of classical Rett syndrome will have all of the main criteria while those with atypical Rett syndrome may only have some (2 out of 4). Main criteria are listed below. For diagnosis of atypical Rett syndrome, at least 5 supportive criteria (listed below) must also be present. (Who Does Rett Syndrome Affect?, n.d.)
The following exclude a diagnosis of classical Rett but may be present in atypical Rett syndrome: Brain injury due to trauma, neurometabolic disease, severe infection causing neurologic problems or grossly abnormal development in the first 6 months of life. (Who Does Rett Syndrome Affect?, n.d.)
Main Criteria:
• Partial or complete loss of acquired purposeful hand skills
• Partial or complete loss of acquired spoken language
• Gait abnormalities
• Stereotypic hand movements such as wringing, squeezing, clapping, tapping, mouthing or hand-washing movements
Supportive Criteria:
• Breathing disturbances when awake
• Tooth grinding when awake
• Impaired sleep
• Abnormal muscle tone
• Peripheral vasomotor disturbances
• Growth retardation
• Small cold hands and feet
• Inappropriate laughing/screaming spells
• Diminished sensitivity to pain
• Intense eye communication and eye-pointing behaviour (Who Does Rett Syndrome Affect?, n.d.)
If the diagnosis of Rett syndrome is suspected, a blood test looking for the mutation on the X chromosome of the gene called MECP2 should be obtained.
Although assumed to be a neurodegenerative disorder, it is categorized as a neurodevelopmental disorder. RTT affects the nervous system and leads to developmental reversals. RTT causes problems in brain function that are responsible for cognitive, sensory, emotional, motor and autonomic function. These can include learning, speech, sensory sensations, mood, movement, breathing, cardiac function, and even chewing, swallowing, and digestion. The severity of effects vary from one individual to another. (Case-Smith & O'Brien, 2010)
Rett syndrome has been most often misdiagnosed as autism, cerebral palsy or non-specific developmental delay.
Causes:
Most cases of Rett syndrome are caused by a mutation on the MeCP2 gene found on the X-chromosome. This gene is responsible for regulating protein production that promotes healthy brain development. When affected, it may under or over regulate the production and cause detrimental damage. (Who Does Rett Syndrome Affect?, n.d.)
It is almost only seen in girls due to the location of the mutation. Girls have to X-chromosomes whereas boys only have one. If a mutation is present in one X-chromosome of a female, the second normal function MeCP2 gene will attempt to compensate and allow the individual to survive. Contrarily, boys who have this mutation do not have the protective factors of a normal functioning gene on the second X-chromosome. Boys with a MeCP2 mutation often die before or shortly after birth. (Who Does Rett Syndrome Affect?, n.d.)
Rett Syndrome Inherited?
Typically the mutation is new having occurred during the replication/division of the chromosomes during formation. Thus most Rett syndromes occur randomly, rather than being inherited.
Progression of RTT
THE AGE WHEN RTT BEGINS AND THE SEVERITY of different symptoms may vary. The child with RTT is usually born healthy and shows an early period of apparently normal or near normal development until six to eighteen months of life, when there is a slowing down or stagnation of skills. (Hunter, 2007)
Children with Rett syndrome undergo four stages of the disease:
Stage 1: early signs and slow development
- Floppiness
- Not interested in toys
- Walking/crawling awkwardly
- Signs of this stage usually appears in the first 6 – 18 months,
- Occurs between the ages of 1 and 4 years old
- May last for weeks or months
- Sudden onset of communication difficulties
- Distressed for no known reason
- Socially uninterested
- Difficulty sleeping
- Difficulty eating
- Plateau following regression, occurring between the age of 2 and 10
- Can last for years
- Unable to use hands effectively
- Teeth grinding
- Can last for a significant period of time
- Spasticity
- Scoliosis (bending of the spine)
- Losing the ability to walk (Hunter, 2007)
How is Rett Syndrome Diagnosed?
How Rett syndrome manifests itself and progresses varies from child to child. In most cases, the correct diagnosis can be made through a blood test(s) to identify the mutation of the MECP2 gene. But since the MECP2 mutation can also be found with other disorders, this finding alone is not enough to make a conclusive diagnosis of Rett syndrome. (Who Does Rett Syndrome Affect?, n.d.)
There are specific diagnostic criteria for typical/classical and for atypical/variant Rett syndrome. Both require that the child have had a period of regression in developmental skills followed by stabilization and/or improvements. (Who Does Rett Syndrome Affect?, n.d.)
A case of classical Rett syndrome will have all of the main criteria while those with atypical Rett syndrome may only have some (2 out of 4). Main criteria are listed below. For diagnosis of atypical Rett syndrome, at least 5 supportive criteria (listed below) must also be present. (Who Does Rett Syndrome Affect?, n.d.)
The following exclude a diagnosis of classical Rett but may be present in atypical Rett syndrome: Brain injury due to trauma, neurometabolic disease, severe infection causing neurologic problems or grossly abnormal development in the first 6 months of life. (Who Does Rett Syndrome Affect?, n.d.)
Main Criteria:
• Partial or complete loss of acquired purposeful hand skills
• Partial or complete loss of acquired spoken language
• Gait abnormalities
• Stereotypic hand movements such as wringing, squeezing, clapping, tapping, mouthing or hand-washing movements
Supportive Criteria:
• Breathing disturbances when awake
• Tooth grinding when awake
• Impaired sleep
• Abnormal muscle tone
• Peripheral vasomotor disturbances
• Growth retardation
• Small cold hands and feet
• Inappropriate laughing/screaming spells
• Diminished sensitivity to pain
• Intense eye communication and eye-pointing behaviour (Who Does Rett Syndrome Affect?, n.d.)
If the diagnosis of Rett syndrome is suspected, a blood test looking for the mutation on the X chromosome of the gene called MECP2 should be obtained.
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Above are videos of young girls displaying stereotypic hand movements commonly found in RTT
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References
Case-Smith, J., & O’Brien, J.C. (Eds.) (2010). Occupational therapy for children (6th ed.). Maryland Heights, MO: Mosby Elsevier
Hunter, K (2007). The Rett Syndrome handbook: In words you can understand from those who understand. International Rett Syndrome Association.
Who Does Rett Syndrome Affect? (n.d.). My Child Without Limits RSS. Retrieved July 20, 2014, from http://www.mychildwithoutlimits.org/understand/rett-syndrome/who-does-rett-syndrome-affect/
Videos sourced from youtube.com
http://youtu.be/J8N48kOtQRIhttp://youtu.be/53k1EsP5D8k
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References
Case-Smith, J., & O’Brien, J.C. (Eds.) (2010). Occupational therapy for children (6th ed.). Maryland Heights, MO: Mosby Elsevier
Hunter, K (2007). The Rett Syndrome handbook: In words you can understand from those who understand. International Rett Syndrome Association.
Who Does Rett Syndrome Affect? (n.d.). My Child Without Limits RSS. Retrieved July 20, 2014, from http://www.mychildwithoutlimits.org/understand/rett-syndrome/who-does-rett-syndrome-affect/
Videos sourced from youtube.com
http://youtu.be/J8N48kOtQRIhttp://youtu.be/53k1EsP5D8k