Transcript Document

Behavioural phenotypes
Dr. Gemma Griffith
[email protected]
Outline
• What is a behavioural phenotype?
• Examples of behavioural phenotypes
– Cornelia de Lange Syndrome
– Cri du Chat Syndrome
• All video clips come from ‘The Three Syndrome
project’ research conducted with Birmingham
University and IoP, London during my PhD.
What is a behavioural phenotype?
• The definition currently accepted by the majority of researchers in
the ID field was proposed by Dykens (1995) which is;
• “a behavioural phenotype is the heightened probability or
likelihood that people with a given syndrome will exhibit certain
behavioural and developmental sequelae relative to those without
the syndrome” (pg 523).
• So, although genetic disorders have a similar origin (e.g missing
part of chromosome), there may be great range of cognitive/
behavioural strengths and weaknesses within a syndrome.
• Particular behaviours and cognitive profiles are more likely, but
are not inevitable.
• This means there can be great variability between individuals with
the same syndrome.
Cornelia de Lange syndrome (CdLS)
• First recognised in 1916.
• It is estimated that the incidence of Cornelia de Lange
Syndrome is between 1 in 10,000 - 25,000 live births.
Cornelia de Lange syndrome
• Physical features
• often short in stature and below average weight when
compared to others their age.
• The facial characteristics of Cornelia de Lange Syndrome
are often striking,
• Features include:
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thin eyebrows which meet in the middle
long eyelashes,
a short upturned nose
thin down-turned lips
low-set ears
• Limb abnormalities including missing
portions or shortening of limbs - usually fingers,
hands or forearms.
Communication in CdLS
• Approximately 60 to 85% of children and adults
with Cornelia de Lange Syndrome do not develop
verbal communication skills.
• Expressive communication skills (ability to
express oneself) are significantly more impaired
than receptive language skills (ability to
understand communication).
• Passivity
Cri du Chat Syndrome (CdC)
• Cri du Chat Syndrome was first identified in 1963
and is so named because of a distinctive ‘cat-like’
high-pitched cry which can be shown by some
children who have the syndrome.
• Cri du Chat Syndrome is a rare genetic disorder
that affects approximately 1 in 37,000 to 50,000
live births.
CdC syndrome-physical features
• The larger the size of the chromosomal deletion, the more
pronounced the physical characteristics are among
individuals with Cri du Chat Syndrome.
• Physical features include:
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Rounded face
Widely spaced eyes
Ears that are positioned low on the head
Poor muscle tone (hypotonia)
Microcephaly (small head size)
A tendency to be shorter and lighter than their
peers throughout childhood and adolescence
Communication in CdC
syndrome
• Most people with CdC have much greater
receptive language then expressive language. So
are able to follow conversations and understand
complex instructions, but expression/
pronunciation is often poor.
Communication in CdC
syndrome
• The high motivation to communicate combined
with the difficulties in expressive communication
can be extremely frustrating for people with CdC
syndrome and may underlie a lot of the
challenging behaviours
Main points
• From the video clips, you can see that there is a strong
desire to interact and communicate with other people in
people with Cri du Chat syndrome.
– Difficulty in communicating may underlie many challenging
behaviours in Cri du chat syndrome.
– We rarely see people with Cornelia de Lange syndrome
getting frustrated about not being able to communicate
complex information. Sociability is less pronounced
– Therefore, heightened sociability is a relative strength
among people with Cri du Chat syndrome, and is therefore
part of the behavioural phenotype.
Thank you
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