A mutation is the changing of a gene’s structure, resulting in a various form that may be passed down throughout generations, that is caused by the change of single base units in DNA, or the deletion, insertion, or substitution of larger sections of the genes or chromosomes. Insertions are extra base pairs that are added, deletions are base pairs that are removed from the DNA, point mutations is when a base pair exchanges one base for another. A type of genetic disorder is called Clinical Depression, which is also a mental disorder.Depression is known as a genetic, mental, and mood disorder that causes a constant feeling of extreme sadness and loss of interest in what a person used to consider fun. Depression is a disorder that ranges from mild to extreme. Clinical Depression, which is also known as Major Depression or Major Depressive Disorder, is a more severe type of Depression. The first symptoms of Depression that were recorded somewhere between 460-370 BCE, they were written by Hippocrates, a Greek physician. During the time, Clinical Depression was called and was classified as mania, melancholia, and phrenitis. Depression, however, is now classified as its own mental disorder. Some symptoms of Clinical Depression are: feelings of sadness, emptiness, irritability, frustration, worthlessness, guilt, anxiety, agitation, restlessness, a loss of interest in most or all normally enjoyable activities, either sleeping too much too little, suffering from insomnia, fatigue, a loss or increase of appetite, slowed thinking, speaking, body movements, having trouble thinking, trouble to make decisions, trouble with memory, having frequent or reappearing thoughts or attempts of suicide, and physical problems that happen for no reason. These are the symptom criteria for Clinical Depression in the “Diagnostic and Statistical Manual of Mental Disorders”, which is published by the “American Psychiatric Association”, used by doctors.The chromosomes that cause or are or may be linked to Clinical Depression are chromosome 11, chromosome 15, chromosome 21, chromosome 3, chromosome 2. The genes that are or may be linked to Clinical Depression are the genes 5HTTP/SLC6A4, APOE, DRD4, GNB3, HTR1A, MTHFR, SLC6A15, and SLC6A3.”The World Health Organization” estimated that ten to fifteen percent of the population will experience Clinical Depression during their lifetime. Women have double the chance of having Depression compared to men, since five percent of men and nine percent of women will experience a depressive disorder in a year. Clinical Depression occurs in all ethnicity and age groups. The age group that Clinical Depression occurs in the most are teenagers to young adults.Treatments used for Clinical Depression are medication, such as selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, atypical antidepressants, tricyclic antidepressants, monoamine oxidase inhibitors, and other medications. Other than antidepressants and other medicine, things like psychotherapy, electroconvulsive therapy, and transcranial magnetic stimulation are some other ways that are used to treat Clinical Depression.Not only is Clinical Depression a mental and mood disorder, it is also a genetic disorder. Clinical Depression is not only caused by outside factors, it can also be passed down from generation to generation through genes.