A genetic study of an early onset form of heart disease identifies 10 families containing members with the condition. No clear dominant or recessive pattern of inheritance is evident, but an analysis of SNP markers for five families detects a strong association with a marker on chromosome 12, and genetic linkage analysis for the marker produces a lod score of 2.2.

What do the association and lod score results suggest about this genetic marker?

Key Concepts

SNP Markers

Single Nucleotide Polymorphisms (SNPs) are variations at a single position in a DNA sequence among individuals. They are commonly used in genetic studies to identify associations between specific genetic markers and diseases. In this context, the strong association with a marker on chromosome 12 suggests that this SNP may play a role in the early onset form of heart disease observed in the studied families.

Lod Score

The lod score (logarithm of the odds) is a statistical measure used to evaluate the likelihood that two loci are linked, compared to the likelihood that they are not linked. A lod score of 2.2 indicates a significant probability of linkage between the genetic marker and the disease trait, suggesting that the marker on chromosome 12 is likely associated with the genetic basis of the heart disease in the studied families.

Genetic Linkage

Genetic linkage refers to the tendency of genes located close to each other on a chromosome to be inherited together during meiosis. In this case, the genetic linkage analysis indicates that the marker on chromosome 12 is not only associated with the disease but may also be inherited alongside it, providing insights into the genetic architecture of the early onset heart disease.