2Outline What is a behavioural phenotype? Examples of behavioural phenotypesCornelia de Lange SyndromeCri du Chat SyndromeAll video clips come from ‘The Three Syndrome project’ research conducted with Birmingham University and IoP, London during my PhD.
3What 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.
4Cornelia 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 live births.
5Cornelia de Lange syndrome Physical featuresoften 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:thin eyebrows which meet in the middlelong eyelashes,a short upturned nosethin down-turned lipslow-set earsLimb abnormalities including missing portions or shortening of limbs - usually fingers, hands or forearms.
6Communication in CdLSApproximately 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
7Cri 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.
8CdC 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:Rounded faceWidely spaced eyesEars that are positioned low on the headPoor muscle tone (hypotonia)Microcephaly (small head size)A tendency to be shorter and lighter than their peers throughout childhood and adolescence
9Communication 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.
10Communication 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
11Main pointsFrom 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 pronouncedTherefore, heightened sociability is a relative strength among people with Cri du Chat syndrome, and is therefore part of the behavioural phenotype.