Rett Syndrome is one of the most common neurodevelopmental disorders and intellectual regression in females. Clinical diagnosis has been based on the consensus clinical criteria which were revised over time in order to define basic typical and atypical findings. Patients who have classical certain clinical elements are defined as typical and patients who present with many of the classical clinical findings but lack some of them are defined as atypical cases.
Typical RS diagnostic Criteria:
A period of regression followed by recovery or stabilisation
• Partial or complete loss of acquired purposeful hand skills.
• Partial or complete loss of spoken language
• Gait abnormalities: impaired or absence of ability
• Stereotypic hand movements such as hand wringing/squeezing, clapping/tapping, mouthing, and washing/rubbing automatisms.
Clinical findings of typical RS varies according to neuro-developmental stage. These clinical findings are divided into four main time intervals as follows:
• Early onset (6 months-1 year): Hypotonia, delay in gross motor skills, loss of hand skills/speech, less eye contact, social interaction, and interest in toys.
• Rapid destructive (1 year- 3 years): Autistic features, intellectual disability, hand stereotypes, motor dysfunction, respiratory abnormalities, microcephaly
• Plateau (2 years-10 years): Seizures, improvement of behaviour, eye contact, and hand use
• Late motor deterioration (>10 years): Further motor deterioration, spasticity/dystonia, scoliosis (IVa, loss of ablitiy to walk; IVb, never ambulant)
Atypical cases are also named as variants some of which are categorized into three main groups.
Atypical RS diagnostic criteria are as follows:
• Breathing disturbances while awake.
• Bruxism while awake.
• Impaired sleep.
• Abnormal muscle tone.
• Peripheral vasomotor disturbances.
• Scoliosis/kyphosis.
• Growth retardation.
• Small cold hands and feet.
• Inappropriate laughing/screaming spells.
• Diminished response to pain.
• Intense eye communication: ‘eye pointing’.
Other clinical findings include cardiac (especially prolonged QTc interval), respiratory (Hyperventilation), gastrointestinal (swallowing difficulty, constipation), orthopaedic (contractures, scoliosis, fractures) and psychological/behavioural problems.
We may also divide most common symptoms according to age as follows:
Early onset phase (6-18 months): Developmental arrest, loss of social interaction, decreased eye contact, repetitive hand movements, breathing irregularities.
Rapid Destructive phase (1-4 years): Loss of acquired skills, loss of purposeful hands use, increased severity of breathing irregularities, seizures, decrease in head circumference.
Plateau phase (2-10 years): Progression decreases and stabilizes. Some improvement in hand usage and social interaction. Breathing irregularity continues without progression, motor function and cognitive skills continue to decline.
Later motor deterioration (After 10 years): Severe loss of motor function, increased spasticity, scoliosis.
MECP2