These notes, stimulated by the diagnosis of a local pre-school child, provide a description of the symptoms involved, (genetic) aetiology, and management strategies
This disorder is a rare genetic/neuro-developmental disorder, initially described by Angelman (1965), characterised by severe learning difficulty, particular facial appearance, and an awkward gait plus "jerky" arm movements.
A full delineation of the disorder was set out by Williams and Frias (1982) who referred to four general areas by which a diagnosis is made:
· Heightened probability of limited post-natal growth.
· Severe learning difficulty, with marked delay in reaching motor milestones. Absence of speech. Frequent inappropriate laughter.
· Unusual head shape (a flattening of the back of the head). Ocular anomalies including decreased pigmentation of the choroid and iris. A large mouth with a protruding tongue and widely spaced teeth.
· Ataxia and awkward arm movements. A proneness to seizures and EFO abnormalities. Reduced muscle tone.
Estimates indicate that the incidence of Angelman Syndrome is around 1 in 20,000 live births.
More Detailed Symptom Description
Information from the Angelman Syndrome Foundation of America indicates that the condition may not be recognisable in the early post natal or infancy period, but the most common age of diagnosis is between 3 and 7 years when the characteristic behaviours and features become evident. Developmental histories typically show a normal pre-natal and birth history, but developmental delay is evident by 6-12 months of age.
In all cases, the developmental delay is severe. Speech is particularly affected with absent or minimal use of words with receptive or non-verbal communication skills higher than expressive and verbal skills. There is a disorder of movement or balance, involving an ataxic gait and/or tremors in the limbs. Behaviour is characterised by any permutation of frequent smiling or laughter, a consistently happy demeanour, an easily excitable personality, often reflected in hand-flapping movements, and hyperactivity along with a short attention span.
In the majority of cases, (more than 80%), there will be delayed or uneven growth in head circumference frequently resulting in microcephaly by age 2 years. Seizures will be observed with a typical age of onset before 3 years; and the abnormal EEG pattern will involve large amplitude slow-spike waves.
In many cases (between 20 and 80%), there will be the flattened head shape, protruding or tbrusting tongue, sucking or swallowing difficulty and feeding problems during infancy, pronounced jaw and wide mouth with frequent drooling or chewing movements, strabismus, light hair and eye colour, raised and flexed arm position during walking, increased sensitivity to heat, and sleep disturbance.
Information from the Angelman Syndrome Support Education and Research Trust highlights some positive aspects, notably the sociable and happy nature of the individuals affected; the possibility that comprehension and understanding may be considerable, that some children may learn sign language and use augmentative communication systems; and that sleeping or proneness to seizures improve with age.
In the majority of cases (70%), this syndrome arises from a fault, a deletion, of chromosone 15. When the deletion occurs in the egg, Angelman Syndrome will result; when the fault is within the sperm, Prader-Willi Syndrome will result.
In most cases, the diagnosis is a sporadic occurrence within a family, and the deletion cannot be attributed to any specific environmental pre-natal event or circumstance. However, there have been some reported cases where a sibling has been affected.
In a minority of cases (around 2 or 3%), the syndrome may result from uniparental disomy that is, the child receives both chromosome 15's from the father instead of one from each parent.
A further sub-group of cases may result from re-alignment of familial chromosome 15 where, for example, a piece of chromosome 15 material may be attached to another chromosome (translocation) or becomes inverted. Both translocations and inversions can pre-dispose to miscopies of DNA and lead to deletions.
Finally, a small number of cases may result from mutations in the gene UBE3A which is regarded as the likely causation gene in Angelman Syndrome and whose inactivation or deficit is linked to the other genetic mechanisms associated with the syndrome. This gene appears to be linked to the functioning of the cerebellum and the hippocampus, brain areas responsible for balance/movement and memory/emotion.
In the remainder of cases, no specific cause has been identified.
Intervention and Management
Advice offered by A.S.S.E.R.T. focuses upon the principle of early diagnosis in order that intervention programmes concerned with behaviour, communication, sleep patterns, and social skills may be established as soon as possible. (It is noted by Ruggieri and McShane 1998 that Angelman Syndrome becomes a more frequent diagnostic consideration between 1 and 4 years of age, and that the average age for diagnosis is lower for boys than for girls.)
These same authors highlight the possible significance of seizures among affected children with the corresponding need for medication (and ongoing monitoring of type and dosage) to compensate for the seizures which are observed most commonly to involve absence seizures, tonic-clonic seizures, drop attacks, and myo-clonic seizures. Parental reports suggested that overall seizure improvement was associated with puberty.
The work of Jolleff and Ryan (1993) highlights the very limited expressive language in Angelman Syndrome, but refers also to evidence (e.g. Robb et all 989) that the marked lack of speech is disproportionate to the degree of learning difficulty.
Their own study investigated the common view (e.g. Clayton-Smith 1992) that the children may all need to communicate by sign language or gesture. They noted that many of their Angelman sample appeared unable to use natural gesture or Makaton signs in a functional way to indicate their needs. This finding raised the questions whether the children have specific problems in planning and implementing motor activities, including speech; whether there is a fundamental problem in using communication for social interaction; and whether the primary difficulty relates to low developmental age.
The implication is for close observation/assessment on the part of the speech and language therapist to determine a given child's "style" and the presence of gross, fine and oral motor control in order to establish the most viable programme by which to facilitate communication.
The need for individual assessment is reinforced by the survey of Alvares and Downing (1998) which demonstrated the wide range of communicative abilities reported in a sample of children with Angelman Syndrome, and which suggested that one should avoid underestimating potential for symbolic and social communication. They, too, stress the critical issue of the choice of communicative modality.
Behaviour difficulties, according to the survey of Clarke and Marston (2000), are largely a matter of overactivity, restlessness, eating disorder and sleep problems. Evidence indicates that the hyperactivity does become less of a problem with increasing age, although there is still some question whether there is a real age effect or whether the observation is a function of the particular sample studied. There is also the suggestion that behavioural management strategies can be effective, but that the initial planning should determine whether parents are giving direct behavioural observations or reporting behaviours believed to be associated with this syndrome. Such a step will not only be valuable in terms of individual strategy planning, but helpful also in respect of gaining more specific data about the prevalence of particular behavioural symptoms as a means of increasing the accuracy of diagnosis.
In respect of hyperactivity and difficulty in initiating or maintaining sleep, the work of Zhdanova et al (undated) has shown that low dose melatonin (0.3 mg of melatonin administered between half an hour and one hour before normal bedtime) with children in the age range 2-10 years significantly reduces motor activity and promotes sleep.
Children with Angelman Syndrome are all likely to require a place in a school which provides for severe learning difficulty.
The advice of Summers et al (1995) holds that the curricular emphasis would be upon the development of functional communication and self-help skills, and the improvement of attention and concentration spans. Behavioural techniques, shared with the parents, would target any signs of aggression (which may be seen among older children), mouthing objects, or other maladaptive performance.
Meanwhile, according to individually assessed needs, there may be requirements for physiotherapy, occupational therapy to develop fine motor and oral-motor control, access to specially adapted chairs, and speech therapy focusing largely on non-verbal means of communication.
Alvares and Downing (1998). A survey of expressive communication skills in children with Angelman Syndrome. American Journal o fSpeech-Language Pathology 7.2. 14-24
Angelman H. (1965). "Puppet" Children: a report on 3 cases. Dev. Med. Child. Neurol 7
Angelman Syndrome Foundation 2000. Angelman Syndrome http://www.angelman. org/two_page_a.htm Wesimont Illinois: ASF
Angelman Syndrome Support Education and Research Trust (undated). What is Angelman Syndrome? Sittingbourne A.S.S.E.R.T.
Clarke D and Marston 0 (2000). Problem behaviours associated with ISq Angelman Syndrome. American Journal on Mental Retardation 105 (1) 25-31
Clayton-Smith J(1992). Angelman Syndrome. Archives of Disease in Childhood 67 889-
Jolleff N and Ryan M (1993). Communication development in Angelman Syndrome. Archives of Disease in Childhood 69 148-150.
Robb S, Pohi K, Baraitser M, Wilson 3, and Brett E. (1989). The 'happy puppet' syndrome of Angelman: review of the clinical features. Archives of Disease in Childhood 64 83-86.
Ruggieri M and McShane M (1998). Parental view of epilepsy in Angelman Syndrome. Archives of Disease in Childhood 79 423-426.
Summers 3, Allison D, Lynch P, and Sandler L (1995). Behaviour problems in Angelman Syndrome. Journal of intellectual Disability Research 39(2) 97-106.
Williams C and Frias 3(1982). The Angelman ("Happy Puppet") Syndrome. American Journal of Medical Genetics 11 453-460.
Zhdanova M, Wurtman R and Wagstaffj (undated). Melatonin and Sleep in Angelman Syndrome. Cambridge MA: Department of Brain and Cognitive Sciences, M.I.T.
© Mike Connor 2001.
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