Molecular Tools for Screening and Diagnosis Flashcards
(14 cards)
What is linkage analysis?
A method using DNA polymorphisms as markers to determine inheritance of chromosome segments containing disease-causing mutations.
What are DNA polymorphisms?
Variations in DNA sequences such as single nucleotide polymorphisms (SNPs) and short tandem repeats (STRs).
What are the advantages of indirect diagnosis?
Does not require knowledge of the disease-causing gene and can indicate inheritance of chromosome regions.
What are the disadvantages of indirect diagnosis?
Requires testing multiple family members, markers may be uninformative, and recombination can introduce errors.
What is direct mutation analysis?
A method detecting the disease-causing mutation directly, without needing family information.
What is one advantage of direct diagnosis over indirect diagnosis?
No errors resulting from recombination.
Name two methods of direct genetic testing.
- Fluorescence in situ hybridization (FISH)
- Array comparative genomic hybridization (array CGH)
What is one challenge associated with genetic testing?
No genetic test is 100% accurate.
What is a limitation of genetic testing in detecting mutations?
Many genetic tests lack sensitivity, often below 90% for certain conditions like cystic fibrosis
This means that some mutations that can cause a disease may not be detected.
What can improve diagnostic accuracy when multiple family members are affected?
The analysis of linked markers
This can help identify causal variants that may not be conclusively identified through standard testing.
What do whole-exome and whole-genome sequencing allow for?
Detection of nearly all disease-causing variants in an individual’s genome
This approach overcomes limitations of targeted sequencing.
What challenge is presented by the large amount of data from exome and whole-genome sequencing?
Differentiating pathogenic variants from benign variants
Many variants are of uncertain significance, complicating interpretations.
What has increased the speed and accuracy of genetic screening and diagnosis?
The use of microarrays and high-throughput sequencing
These technologies have revolutionized genetic testing.
What challenges are raised by exome and whole-genome sequencing?
- Large numbers of variants of uncertain significance
- Issues regarding reporting incidental findings
These challenges complicate the interpretation and communication of genetic test results.
