Brief Introduction, History, Symptoms, and Diagnosis

Brief Introduction

Rett is an autism spectrum disorder that mainly effects girls.

First, I want to provide you with a brief introduction to Rett Syndrome. Rett syndrome is classified as an autism spectrum disorder. It is a neurodegenerative disease, meaning that the child with the disorder will develop normally, hitting all major developmental milestones, for about 6 to 18 months. Then the child will regress, and lose verbal, motor, and cognitive abilities. Many people with Rett Syndrome are non-verbal, and communicate with an intense stare. There is also a hand wringing gesture, which becomes more common as the child loses purposeful hand movements. Many other symptoms, which will be discussed at a greater length, accompany this disorder.
The thing that intrigued me about Rett Syndrome is that it mainly occurs in girls. Most boys born with Rett syndrome will die prematurely. Genetic research  provided the answer as to why girls are able to survive with Rett while boys are typically unable to live with the condition.   It occurs in one in every 10,000 to 15,000 live female births. All socioeconomic, racial and ethnic groups are affected by this disorder. It is unlikely (about 1%) that a family will have a second daughter with Rett Syndrome. There are family cases of Rett Syndrome, which account for about 1% of all total cases of the disorder. There are many familial cases occur in Northern Tuscany, islands of Western Norway, and Sweden. If you have a child with Rett Syndrome prenatal testing is available, since we know the genetic cause of Rett Sydrome to detect if a second child has the disorder.

History

Rett syndrome was first described in 1966 by a doctor named Andreas Rett. . He noted two young girls rocking back and forth and constantly wringing their hands, which is the  stereotypical hand movement of Rett syndrome. He was able to find 6 other patients with similar symptoms. In 1966, he reported on studies of 22 different girls. A lack of an English description of the disease contributed to a lack of interest in the disorder. Dr. Rett contributed publications in Germany from 1966 to 19695. In 1972, a German publication recorded the disease as Rett Syndrome. In 1977, Dr. Rett provided a more extensive English description of the disorder. More cases of girls with similar symptoms awakened interest in the English speaking world, and the disorder received recognition. Today, it is a well-researched disorder that has a clear genetic origin and well described symptoms.

Example of the handwringing gesture observed by Dr. Rett. 

Diagnosis and Symptoms

Rett syndrome can either be diagnosed by assessing clinical criteria, or with genetic testing. Most commonly the physician will use the clinical criteria, and then may use a genetic test to confirm Rett Syndrome. The tests look for a mutant (altered) copy of the MeCp2 gene.

To diagnosis a child with typical or classical Rett Syndrome, there must be a period of growth followed by regression, there must be all of the Main criteria present, and none of the exclusion criteria, and it is likely that some of the supporting criteria is present, but it is not needed for a diagnosis of Classical Rett Syndrome. In contrast, a diagnosis of Aptypical Rett Syndrome involves a period of regression followed by a recovery or stabilization, at least 2 of 4 main criteria, and 5 of 11 of the supportive criteria. Below the main, exclusion, and supportive criteria are listed:

• Criteria Main Criteria
• Partial or complete loss of acquired purposeful hand skills
•  Partial or complete loss of acquired spoken language
•  Gait abnormalities: Impaired or absence of ability
•  Stereotypic hand movements such as hand wringing/squeezing, clapping/tapping, mouthing and washing/rubbing 
• Exclusion criteria for typical Rett
•  Brain injury after trauma , neurometabolic disease, or severe infection that causes neurological problems
•  Grossly abnormal psychomotor development in first 6 months of life
• Supportive criteria for Rett
•  Breathing disturbances when awake
•  Bruxism (clenching or grinding of teeth) when awake
•  Impaired sleep pattern
•  Abnormal muscle tone
•  Peripheral vasomotor disturbances (problems with cold, blue hands and feet)
• Scoliosis/kyphosis (curving of spine)
•  Growth retardation
•  Small cold hands and feet
• Inappropriate laughing/screaming spells
•  Diminished response to pain
• Intense eye communication

Typical Rett syndrome tends to follow a course, or stages. The stages are outlined below

At first, it is not obvious that a child has Rett.

•  Stage 1 – Early Onset Stagnation Period
• Starts at 6 to 18 months 
•  Not often noticed
•  Less eye contact, less interest in toys, may need less attention, may be irritable and restless
•  May be delays in skills like sitting or crawling, but it is not very noticeable
• Lasts for a few months, but can last for over a year
• Stage 2- Rapid Development Regression Period
• Starts between 1 year to 4 years
• Can last weeks or months
• Hand skills and expressive language can be lost
•  Abnormal Hand movements begin
• Breathing irregularities and irritability
•  Loss of social interaction and communication
•  May have unsteady walking gait and trouble starting movements
•  May develop seizures
• Decline of head growth can be noticed
• Stage 3- Pseudo-stationary Period
•  Starts between 2 and 10 years
•  Lasts most of life
• Apraxia, or being unable to perform complex movements and seizures are common
•  Impairments in hand functioning become more obvious
• Behavior like irritability and crying may improve
•  May have more interest in outside world
• May make better eye contact and use gaze to communicate
•  May start to learn about new things

  

  A child  who has lost mobility due to Rett.

• Stage 4- Late Motor Deterioration Stage
•  Can last for years or decades
•  Starts when ability to move around is lost
•  Characterized by muscle weakness, rigidity (stiffness), spasticity (uncontrolled muscle activity), dystonia (increased muscle tone with abnormal posturing of extremity or trunk) and scoliosis (curvature of the spine)
•  Hand movements become less intense
•  Eye gaze continues