How does the size of the genetic fault you are looking for influence the genetic test you do ?
Describe array comparative hybridisation testing
Array Comparative Genomic Hybridisation allows identification of regions of the genome that are deleted or duplicated in a patient by comparison with a control DNA sample.
Each dot on a microarray represents a specific genetic region. If more patient DNA than control DNA hybridises to the dot, it suggests that the region is duplicated in a patient.
If less patient DNA hybridises than control DNA, then the region is deleted in the patient.
Only detects chromosome inbalance i.e. not useful for balanced translocations
How do we know a genetic change causes a disease ?
If the gene matches the phenotype -i.e. if the patient has 2 heads and it’s the gene which causes 2 heads then the gene matches the phenotype
What is meant by a de novo mutation ?
When a genetic mutation occurs when a sperm fertilises an egg, or when cells are dividing after fertilisation. i.e. it is only present in the child
Match the different type of mutation in the DNA sequence to the sentence:
•The cat sat on the mat
•The car sat on the mat
•The cat spa to nth ema t
•The cas ato nt hem at
•The cat on the mat
•The cat cat sat on the mat
Wild type, instertion, triplet expansion, deletion (in frame), missense, deletion (out of frame), stop (nonsense)
- The cat sat on the mat - Wild type
- The cat - stop
- The car sat on the mat - Missense
- The cat spa to nth ema t - Insertion
- The cas ato nt hem at - Deletion (out of frame)
- The cat on the mat - Deletion (in frame)
- The cat cat sat on the mat - Triplet expansion
What is meany by causative mutation ?
It is the mutation associated with the phenotype
Define intellectual disability as per the education department
Those children and young people who have either a learning difficulty in relation to acquiring new skills or who learn at a different rate to their peers.
What are the 3 main areas you should consider when thinking about someone potentially having intellectual disability ?
- Conceptual (ability to learn)
- Social (ability to interact)
- Practical (ability to dress themselves etc)
What are some of the first line investigations to consider doing after history and examination for kids who possibly have a genetic disorder ?
- Creatinine Kinase, TFT’s, U+E’s, bone group, LFT’s, FBC and film
- Chromosomal microarray, Fragile X