Genetic disorders occur when abnormalities emerge in the unique genome of an individual. Genetic disorders are inherited when defective genes from one or both parents are passed to offspring. In some cases, a genetic disorder is simply a novel change (mutation) affecting a person’s DNA.
Single gene disorders resulting from one mutated gene constitute nearly 4,000 diseases currently known to exist. Capable of being passed down through many generations, single-gene disorders involve dominant and recessive gene types, with genetic disorders depending on “recessive” genes lying dormant for three or four generations before they inexplicably emerge again.
In 2018, scientists discovered that autism, schizophrenia, ADHD, bipolar disorder and depression are, in fact, traceable to certain inherited gene variations. Results of a large genome-wide study found that these genetic variations may account for nearly 28 percent of a person’s risk for mental illness.
Scientists also learned that shared variants such as mutations, deletions, duplications and gene-environment correlations further contributed to the emergence of mental disorders. In addition, studies suggest there may be an overlap among these five mental disorders, meaning some genes may carry markers for multiple mental illnesses.