Atypical development Flashcards
Basic genetics
Every cell in our body contains DNA
DNA contains instructions for building proteins. this is the basis for all our development.
DNA is packed into genes. Human’s have about 21,000 genes.
Genes are found in chromosomes, each chromosome contains 100s to 1000s of genes
How do geneticists label parts of the chromosome
Chromosome arm- on each chromosome, there is a short arm (labelled p for petite) and a longer arm (labelled q)
Chromosome region- labelled with numbers, with lower numbers representing a region of the chromosome that is closest to the centre
Genetic abnormalities
Can occur when there are too many or too few occurrences of particular genes. For example some people have extra chromosomes (e.g. people with Down’s syndrome have an additional copy of chromosome 21), other people can have parts of chromosomes that are either duplicated or deleted. This means that there are extra copies of some genes or missing copies. These are called copy number variants
16p11.2
Deletion- obesity, macrocephaly
Duplication- low BMI, microcephaly
William’s syndrome
Caused by spontaneous deletion at chromosome 7q11.2
Characterised by a distinct facial appearance, cardiac anomalies, highly social personality
Effects 1 in 10,000 people
Contrast between visio-spatial and language abilities- can speak/write clearly but can’t draw what they are describing
FASD
Alcohol is a teratogen- an agent which causes change in an embryo
Ethanol (compound within alcohol) is thought to alter DNA and protein synthesis and inhibit cell migration, leading to an array of physical and cognitive changes
Intellectual disability
Often co-occurs with other neurodevelopmental conditions e.g. autism, FASD
Affects 10.4 people in every 1000
Diagnosis based on IQ evaluation as well as investigation of adaptive behaviour, classed as mild, moderate, severe or profound
