Weathering and erosion. Weathering is the process where rock is dissolved, worn away or broken down into smaller and smaller pieces. There are mechanical, chemical and organic weathering processes.
What is trinucleotide repeat disorders? A class of genetic diseases that causes expansion of the number of trinucleotide (three base repeats of CG-rich units) within a gene sometimes associated with deleterious consequences.
Huntington's disease is inherited in an autosomal dominant manner, but it's an expansion defect as well. Let's start with understanding the expansion part first. Huntington's disease is caused when a person has 36 or more CAG repeats in one of their two HHT genes. Normally, a person has 26 or less CAG repeats.