Genetic Basis of AMD

Genetic Basis of AMD

AMD results from a combination of environmental and genetic factors. Environmental factors associated with AMD include age, gender, smoking and diet. Evidence for genetic risk has also been supported by several family studies and twin studies. Results from these studies revealed that people with an affected parent have approximately twice the risk of getting AMD than someone whose parent does not have AMD.

DNA is the chemical in our cells that gives our bodies instructions about how to grow, develop and function. DNA is a string of coded messages organised into specific instructions called genes. Humans have 30,000 different genes, arranged on a number of thread like structures, called chromosomes. We inherit our chromosomes from our parents, 23 from our mother and 23 from our father, so we have two sets of 23 chromosomes, or 23 ‘pairs’. A good description is If you think of genetics as the book of life, then the DNA are the letters, the genes are words, and the chromosomes are the chapters.

If you think of a mutation as a spelling mistake or a series of words changed in a sentence, then this causes a problem in the meaning and interpretation and it is just this that happens when there is a mistake or a mutations occurs in a gene – it can cause a condition like inherited AMD.
Sometimes a mutation will have no effect at all. This depends on environmental factors, an element of chance, or mutations in other genes. Mutations can cause problems if they stop the gene or chromosome communicating the correct instructions needed for the body to function properly.

In the largest study of the complete set of human genes to date, it was reported that AMD is associated with a number of types of mutations, 45 common single nucleotide polymorphisms (SNPs) and 7 rare variants across 34 genetic loci, which explain 34% of AMD risk¹. Many of these genetic variants reside in the complement factor H (CFH) gene on chromosome 1 and ARMS2/HTRA genes on chromosome 10. Other variants can be seen in and around genes involved in the cholesterol metabolism, collagen production and cell signalling. This suggests that AMD is a complex disease associated with multiple genetic risk factors².

A detailed insight into our current knowledge around Genetics and AMD is available to read via the link provided below: Genetics and AMD.

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