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Three significant elements must be examined clinically to diagnose a genetic disease. First, physical examination must take place, then a background study of the patient's medical history, and, finally, laboratory and clinical testing. Even though primary care providers cannot always diagnose genetic diseases comprehensively, their role is vital in collecting detailed family history, considering genetics in differential diagnoses, ordering testing when appropriate, and, when necessary, referring patients to genetic specialists. [1]
A differential diagnosis may include genetic diseases because of several factors. When obtaining the family history, it is often found that certain conditions are present among multiple family members. Genetic diseases can be diagnosed when a patient suffers the same condition found in more than one family member (especially first-degree relatives). Family histories of developing common adult illnesses in two or more relatives at relatively young ages (e.g., heart disease, cancer, dementia) may also indicate a genetic predisposition. It should be noted, however, genetic conditions can also present in youth or adulthood. Genetic diseases are often detected during puberty or pregnancy when symptoms manifest, especially when toxic metabolites accumulate. A genetics specialist should be referred to patients based on detailed family history and physical examination. [1]
Genetic tests fall into the following categories [2]:
• You can predict the risk of developing a particular disease through predictive genetic testing, regardless of whether someone has a family history. Examples would be certain types of cancers and heart disease.
• The presymptomatic genetic test can help determine if a genetic alteration is associated with a disease in a person with a family history of the disease.
• It is possible to determine if someone carries one copy of a gene associated with a specific disease through carrier testing. "Autosomal recessive" diseases are those whose symptoms are brought about by two copies of the altered gene inherited from both parents. Each pregnancy ends with a 25% chance for a child born with a medical condition caused by both parents carrying the same autosomal recessive gene.
• A prenatal diagnosis examines the developing fetus to diagnose genetic diseases or disorders. There are prenatal screening blood tests, ultrasounds (sonograms), amniocenteses, chorionic-villus samplings (CVS), and percutaneous umbilical blood samplings (PUBS).
• Genetic diseases can be detected using preimplantation studies before an embryo is implanted inside the mother's womb during in vitro fertilization (IVF).
• Genetic screening is used to identify disorders in newborns that can be treated before they cause serious health issues.
Using genetic research, we can learn more about how diseases are caused so that new approaches to treating and preventing them can be devised. Today's technology allows us to analyze almost one million sites in any individual's genomic DNA, simultaneously, to find correlations between disease and genetic variants. The genetic study of disease presents scientists with new challenges, including handling the millions of data points involved. Research, today, generates an increasing amount of data, which requires improving mathematical and statistical models. In addition, disease definitions need to be rethought. Scientists now know that many diseases have a complex genetic component, and the same disease may not manifest in the same manner in different people depending on their genetic makeup. Hence, descriptions that include gradients of illness and health are typically more effective than those that label individuals as either sick or healthy. [3]
References:
1. Alliance, G. (2010, February 17). Diagnosis of a genetic disease. Understanding Genetics: A District of Columbia Guide for Patients and Health Professionals. Retrieved March 12, 2022, from https://www.ncbi.nlm.nih.gov/books/NBK132142/.
2. Genetic disorders: Diagnosis & treatments: Boston Children's Hospital. Boston Children’s Hospital. (n.d.). Retrieved March 12, 2022, from https://www.childrenshospital.org/conditions-and-treatments/conditions/g/genetic-disorders/diagnosis-and-treatments#:~:text=Most%20of%20the%20time%2C%20genetic,is%20called%20biochemical%20genetic%20testing.
3. Vieire, A. (2014). Genes and Disease. Nature news. Retrieved March 12, 2022, from https://www.nature.com/scitable/topic/genes-and-disease-17/.
Contributors:
Author: Rayven Hall
Editor: Lauryn Agron
Health scientist: Rayven Hall