Genes are the building blocks of heredity. They are passed from parent to child. They hold DNA, the instructions for making proteins. Proteins do most of the work in cells. They move molecules from one place to another, build structures, break down toxins, and do many other maintenance jobs.
Sometimes there is a mutation, a change in a gene or genes. The mutation changes the gene's instructions for making a protein, so the protein does not work properly or is missing entirely. This can cause a medical condition called a genetic disorder.
You can inherit a gene mutation from one or both parents. A mutation can also happen during your lifetime.
There are three types of genetic disorders:
Single-gene disorders, where a mutation affects one gene. Sickle cell anemia is an example.
Chromosomal disorders, where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. Down syndrome is a chromosomal disorder.
Complex disorders, where there are mutations in two or more genes. Often your lifestyle and environment also play a role. Colon cancer is an example.
A doctor may suspect a diagnosis of a genetic condition on the basis of a person's physical characteristics and family history, or on the results of a screening test.
Genetic testing is one of several tools that doctors use to diagnose genetic conditions. The approaches to making a genetic diagnosis include:
A physical examination: Certain physical characteristics, such as distinctive facial features, can suggest the diagnosis of a genetic disorder. A geneticist will do a thorough physical examination that may include measurements such as the distance around the head (head circumference), the distance between the eyes, and the length of the arms and legs. Depending on the situation, specialized examinations such as nervous system (neurological) or eye (ophthalmologic) exams may be performed. The doctor may also use imaging studies including x-rays, computerized tomography (CT) scans, or magnetic resonance imaging (MRI) to see structures inside the body.
Personal medical history: Information about an individual's health, often going back to birth, can provide clues to a genetic diagnosis. A personal medical history includes past health issues, hospitalizations and surgeries, allergies, medications, and the results of any medical or genetic testing that has already been done.
Family health history: Because genetic conditions often run in families, information about the health of family members can be a critical tool for diagnosing these disorders. A doctor or genetic counselor will ask about health conditions in an individual's parents, siblings, children, and possibly more distant relatives. This information can give clues about the diagnosis and inheritance pattern of a genetic condition in a family.
Laboratory tests, including genetic testing: Molecular, chromosomal, and biochemical genetic or genomic testing are used to diagnose genetic disorders. Other laboratory tests that measure the levels of certain substances in blood and urine can also help suggest a diagnosis.
Genetic testing is currently available for many genetic conditions. However, some conditions do not have a genetic test; either the genetic cause of the condition is unknown or a test has not yet been developed. In these cases, sequencing the entire genome may result in locating the responsible genetic variant. Additionally, a combination of the approaches listed above may be used to make a diagnosis. Even when genetic testing is available, the tools listed above are used to narrow down the possibilities (known as a differential diagnosis) and choose the most appropriate genetic tests to pursue.
A diagnosis of a genetic disorder can be made anytime during life, from before birth to old age, depending on when the features of the condition appear and the availability of testing. Sometimes, having a diagnosis can guide treatment and management decisions. A genetic diagnosis can also suggest whether other family members may be affected by or at risk of a specific disorder. Even when no treatment is available for a particular condition, having a diagnosis can help people know what to expect and may help them identify useful support and advocacy resources.
Information above from Genetics Home Reference. Learn more here.
How Does Pediatric Physical Therapy Help Children With Genetic Disorders?
Physical therapists have a very important role in facilitating a diagnosis by referring, coordinating, and communicating with a clinical geneticist.
Genetic disorders can cause mild or severe developmental disabilities. Syndromes may present characteristic symptom patterns (e.g. facial features, limb length, organ anomalies, abnormal muscle tone and hyper-mobile joints) and they are likely to be at risk for developmental delays in many areas of function which may include: motor planning skills, language and cognitive skills, self care skills (including feeding difficulties) and peer/social engagement.
Some genetic disorders that may be treated by a Pediatric physical therapist include: Trisomy 13/Down syndrome, Trisomy 18, Turner’s syndrome, Muscular dystrophies, Cystic fibrosis, Prader-Willis syndrome, Fragile X syndrome, Williams syndrome, Diabetes, Huntington’s disease, and Angelman syndrome. Skilled PT intervention may include helping with Gross motor skills, Positioning, Strength and Endurance, Orthotics recommendations/management, Respiratory interventions, Equipment Assessment, and foremost Parent Education.
