User:Samanthamcanci/DNA methylation of down syndrome

Down Syndrome
Down syndrome (DS) is a common genetic disorder that is caused by a mutation that leads to the presence of an extra copy of chromosome 21. DS can be associated with cognitive learning disabilities, growth delays and other developmental delays. Down syndrome is incurable, and entails a greater risk for diseases that are related to age, specifically in the brain and immune system. There are many different phenotypes and gene expression patterns of down syndrome, implying epigenetic modification. DNA and histone modification have been seen to contribute to down syndrome.

DNA Methylation
DNA methylation is an epigenetic mechanism that helps regulate gene expression. DNA methylation is responsible for recruiting proteins in gene repression and/or inhibiting the binding of transcription factors to DNA. Genome alterations in individuals with down syndrome have been observed in various tissues from DNA modification. methylation is needed for normal cognitive function; alterations of DNA methylation can lead to developmental mutations. Over expression of HSA21 genes modulate DNA methylation through DNA damage at CpG sites that prevent binding, leading to higher levels of expression.

Chromosome 21 has epigenetic gene modifiers that can contribute to dysregulation. There is an abundant amount of transcription factors on the genome of chromosome 21 that bind to enhancers and promoters that lead to chromatin structure and DNA methylation disruptions. Alterations in genome expressions have been identified at prenatal, postnatal and adulthood stages in individuals with DS, compared to individuals without.