This web page was produced as an assignment for Genetics 564, an undergraduate course at UW-Madison.
The Genetics of Frontotemporal Dementia
Figure 1. General DNA helix. DNA Image Credit
Figure 2. The "Central Dogma" Transcription Image Credit
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The basis of genetics is the study of genes and chromosomes. A single strand of DNA consists of nucleotides (Adenine, Thymine, Cytosine, and Guanine). This stand twists around to form a DNA double-helix structure, which can condense and fold to form a chromosome. To give a general analogy, imagine a regular book. Starting from the smallest component, the letters in each word represent the nucleotides of a given DNA sequence. Those letters comprise the sentences, which are like genes. Further, each page (a chromosome) consisting of many sentences. Together, you get the genome of a person, or an entire book. Humans have 23 pairs of chromosomes, one pair being the chromosomes that determine the sex of the individual. The strands of DNA can be unwound, read, and copied into mRNA strands. This process is called transcription. Those strands are then read and used to piece together amino acids, the building blocks of proteins, in a process called translation.
Mutations generally occur at the nucleotide level, leading to a change in a gene. These changes can have an impact on the expression of a gene, on the amino acid sequence, and ultimately on protein function. Different mutations have different rates of occurrence and different impacts on human health. |
How is FTD inherited?
FTD is largely considered to have an autosomal dominant pattern of inheritance, meaning the mutated gene is not located on a sex chromosome. When a parents' offspring is formed, each parent contributes half of their chromosomes to the newly developing organism. Because the disease is considered dominant, only one copy of the gene is required for the disease to be present. This means only one parent needs to be affected for the disease to pass on to offspring. Multiple mutations have been linked to FTD, the most common being mutations to the microtubule-associated protein tau gene (MAPT) and progranulin (GRN) [1].
Forty mutations have been discovered in the MAPT gene that are linked to FTD. Mutations influence the way cells work and divide; mainly through microtubule assembly, axon transport, and tau filament aggregation. Those with mutations in the MAPT gene tend to have early onset, Parkinsonism, and motor dysfunction. [1] |
Autosomal Dominant Patterns
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Figure 4. General chromosome image. Boxed chromosomes determine sex of the individual. Chromosome Image Credit
REFERENCES
[1] Riedl, L., Mackenzie, I., Förstl, H., Kurz, A., & Diehl-Schmid, J. (n.d.). Frontotemporal lobar degeneration: Current perspectives. Retrieved February 1, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3928059/
[1] Riedl, L., Mackenzie, I., Förstl, H., Kurz, A., & Diehl-Schmid, J. (n.d.). Frontotemporal lobar degeneration: Current perspectives. Retrieved February 1, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3928059/
Site built by Kassandra Ford
Genetics 564, Spring 2015
University of Wisconsin-Madison
Site last updated: 5/13/2015
Genetics 564, Spring 2015
University of Wisconsin-Madison
Site last updated: 5/13/2015