Gene Mutations and Pathogenesis Review

These flashcards cover key concepts related to gene mutations, their types, pathogenesis, and the relationship between genotype and phenotype.

What are the different types of mutations?

Missense, Insertion & deletion, Silent, Splice site, Nonsense, Dynamic.

What causes Huntington disease?

CAG repeat expansion in the HTT gene.

What is the main connection between dynamic mutations and disease?

Dynamic mutations can become unstable above a certain size and are associated with various diseases.

What does anticipation in genetic diseases mean?

Anticipation occurs when a disease manifests earlier and/or increases in severity with successive generations.

Define haploinsufficiency.

A condition where a single copy of a gene is not sufficient to ensure normal function.

What is a gain of function mutation?

A mutation resulting in a gene product that has increased activity or a new function.

What is the role of mutations in protein aggregation?

Certain missense mutations can lead to changes in protein structure, causing aggregation and disease.

What is the phenotype threshold in the context of gene dosage?

The amount of normal active product needed for the manifestation of a disease.

How does Waardenburg syndrome relate to loss of function mutations?

It is caused by various mutations in the PAX3 gene, often resulting in loss of gene function.

What distinguishes dominant negative mutations from other types?

They interfere with the normal function of the protein, leading to more severe disease phenotypes.

Which gene is associated with Charcot-Marie-Tooth disease 1A?

The PMP22 gene.

What is the impact of dynamic mutations like those in Fragile X syndrome?

They involve expansions of CGG repeats in the FMR1 gene leading to cognitive impairments.

What is the relationship between CAG repeat length and the age of motor onset in Huntington disease?

Longer CAG repeats are correlated with an earlier age of motor onset.

What kind of mutations cause Osteogenesis imperfecta?

Mutations in collagen genes, particularly COL1A1 and COL1A2.

What is a common mechanism of gain of function in tumor cells?

Gross overexpression of certain genes or activation of oncogenes.

How does age influence CAG repeat expansions in Huntington's?

Somatic expansions of CAG repeats increase over the course of life.

What are monogenic diseases?

Diseases caused by mutations in a single gene.

How do mutations in collagen genes lead to disease?

They can interfere with normal collagen assembly, leading to conditions like OI.

What are polygenic diseases?

Diseases resulting from the combined effects of mutations in multiple genes.

Explain the role of environmental factors in multifactorial diseases.

Multifactorial diseases arise from the interaction between genetic variants and environmental exposures.

What is the significance of gene/protein dosage in disease manifestation?

The amount of gene product can determine whether a disease manifests, with different thresholds for dominant and recessive mutations.

What defines a null allele in the context of osteogenesis imperfecta?

A mutation that results in a complete loss of function of the gene.

Describe how mutations can cause protein misfolding.

Mutations can alter protein structure, leading to improper folding and dysfunctional proteins.

What is the main consequence of loss of function mutations?

They typically lead to a lack of gene product activity, often resulting in recessive disorders.

How is anticipation diagnosed in families?

By observing a milder form of the disorder in parents or relatives after an index patient exhibits the disorder.

What is the role of the HBB gene in sickle cell anemia?

A missense mutation in HBB causes a change in hemoglobin structure leading to sickle-shaped red blood cells.