What are multiple mutations?
In normal cells, most DNA damage is repaired without error. However, in tumor cells this equilibrium may be skewed, resulting in the accumulation of multiple mutations. Among genes mutated are those that function in guaranteeing the stability of the genome. Loss of this stability results in a mutator phenotype.
Can multiple mutations occur?
These “multiples” appear to be generated by transient, localized hypermutation rather than by heritable mutator mutations. The components of multiples are sometimes scattered at random and sometimes display an excess of smaller distances between mutations.
Can DNA have multiple mutations?
However, based on how a DNA sequence is changed (rather than where), many different types of mutations can occur. For instance, sometimes an error in DNA replication can switch out a single nucleotide and replace it with another, thereby changing the nucleotide sequence of only one codon.
How many mutations are in a tumor?
Recent estimates have put the total number of mutations in a cancer at more than 10,000. There is, moreover, evidence that some benign 8 or supposedly non-neoplastic 9 lesions harbor many or several mutations, although such findings are by no means universal.
What are two gene mutations?
Types of Changes in DNA
| Class of Mutation | Type of Mutation | Human Disease(s) Linked to This Mutation |
|---|---|---|
| Point mutation | Substitution | Sickle-cell anemia |
| Insertion | One form of beta-thalassemia | |
| Deletion | Cystic fibrosis | |
| Chromosomal mutation | Inversion | Opitz-Kaveggia syndrome |
Can a person have multiple genetic disorders?
Conditions caused by many contributing factors are called complex or multifactorial disorders. Although complex disorders often cluster in families, they do not have a clear-cut pattern of inheritance.
What is the evidence for multiple mutations in cancer?
Mutations are heritable changes in the nucleotide sequence of DNA and, as such, include chromosomal abnormalities. Until recently, evidence for multiple mutations in human cancers was based mainly on chromosome aberrations.
How common are multiple mutations in HCM?
Multiple Mutations in Other Genetic Cardiovascular Disorders Although the number of reports are limited to date, it seems that up to 5% of families with HCM have multiple mutations, which include homozygous, double heterozygous, and compound heterozygous carriers.
Can a person have 2 different genetic mutations?
However, most recently, there is an emerging recognition that a proportion of patients carry 2 (multiple) independent disease-causing gene mutations (ie, not polymorphisms), leading to more severe clinical disease. These mutations can occur in the same gene (compound mutation) or in 2 different genes (double mutation), as indicated in Figure 2.
Do multiple genetic mutations have an additive effect on molecular pathogenesis?
The presence of multiple mutations in a number of different genetic cardiovascular disorders, and the association of multiple mutations with a more severe clinical phenotype, suggests the presence of 2 mutations has an additive effect in terms of molecular pathogenesis.