Testing & Diagnosis for Genetic Disorders in Children

Mother of child treated at Boston Children's for profound dyslexia. Boston Children's researchers aim to identify genes that cause dyslexia.

Boston Children's provides genetic testing for pregnant women, newborns and children of all ages. In some cases, a diagnosis can be made after a physical exam. Most of the time, genetic disorders are diagnosed through a specific test, which can include examining chromosomes or DNA (the tiny proteins that make up genes), or testing the blood for certain enzymes that may be abnormal. Studying enzymes is called biochemical genetic testing.

At your initial appointment, a member of the genetics team (a genetic counselor, a clinical genetics fellow, and/or a geneticist) will review your medical, family and pregnancy history and perform tests. Tests may include X-rays, an MRI or genetic tests (usually blood or urine tests). Your child may also be referred to a specialty clinic within the hospital.

The different categories of genetic tests are:

  • Predictive genetic testing: can tell you the chances that a healthy person with our without a family history of a certain disease might develop that disease. These diseases can include some types of cancer and heart disease.
  • Presymptomatic genetic testing: can tell if a person with a family history for a genetic disease but does not have symptoms, has a genetic alteration associated with the disease.
  • Carrier testing: can determine if a person carries one copy of a gene linked to a certain disease. An "autosomal recessive" disease means that the disease will appear only if two copies of the altered gene are inherited. Couples who both carry the same autosomal recessive gene have a one in four, or 25 percent, chance with each pregnancy to have a child with that disease.
  • Prenatal diagnosis: used to diagnose a genetic disease or condition in the developing fetus. Prenatal tests include screening blood, ultrasound (sonograms), amniocentesis, chorionic villus sampling (CVS), and percutaneous umbilical blood sampling (PUBS)
  • Preimplantation studies: are used only in in vitro fertilization to diagnose a genetic disease in an embryo before it is implanted into the mother's uterus.
  • Newborn screening: is used to check for certain genetic disorders that can be diagnosed and treated early in life.