Week 1: How to Read a Genetic Sequencing Test Report
Hello everyone!
This week, I have been reviewing some supplementary material related to genetics. I completed a course on human genetic variation last November, and I spent some time yesterday looking over the content of that course once again. The articles, videos, and lessons I have viewed provide a comprehensive overview of essential tests and technologies related to genetics research. For example, I learned how to read genetic sequencing test reports (explained below):
Genetic Testing Report Example
On the left-most side, the report indicates which gene a genetic variant was found in. In this case, the variant was found in the CDH8 gene. Beside this column is the Disease column, which demonstrates the condition associated with the variant. In this individual, the genetic variant may be linked to Autism Spectrum disorder.
The Variant section of the report describes the specific change to the DNA and amino acid sequences.
c.622G>A
The “c” stands for “coding,” meaning that “c.622G>A” refers to the change in DNA sequencing. At nucleotide position 622, the reference nucleotide guanine (G) has been swapped with adenine (A). While in most cases, a guanine is found in position 622, an adenine is found in this individual.
p.Gly208Ser
The “p” stands for “protein,” which means that “p.Gly208Ser” refers to a change in protein composition. While Glycine is most common at position 208, this individual has a Serine instead. The structural differences in these amino acids contribute to the individual’s condition.
Another important detail that Genetic Sequencing Reports provide is a condition’s Inheritance Pattern. Inheritance patterns reveal whether one or two copies of a variant are needed to cause a condition, and they also show whether a variant is sex-linked (carried on X or Y chromosomes) or autosomal (carried on chromosomes 1-22). The test reports an Autosomal Dominant inheritance pattern, meaning that the individual has at least one copy of the disease-causing variant on their gene.
Similar to inheritance pattern, Zygosity tells whether the variant was found on one or both copies of the gene. This individual is heterozygous, meaning that they have the variant on one copy of the gene.
The genetic testing report provides further information on the variant’s inheritance. The column labeled “Inherited from” conveys whether the variant was inherited from the individual’s parents, or if it is new. This variant is De novo, meaning that it is a new variant in the child.
The “Variant Classification” column on the far right depicts the laboratory’s interpretation of the variant and its relationship to health and disease based on the information available when the variant was reported. In this example, the variant is of uncertain significance, meaning that it has an unclear impact on the individual’s health.
Despite the general knowledge that these resources provide, I have yet to delve into the specific details of my project. Later today, I will go to my site placement to discuss the details of my project going forward. By the end of this week, I plan to sort out my senior project schedule, understand my responsibilities in both individual and team settings, and gain a better understanding of the data analysis tools and genetic sequencing methods I will use. I am looking forward to learning more, and I will keep all of you posted!
-Caitlin
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