How Hereditary Illnesses Work

By: Alvin Eden & Elizabeth Eden

Genetic Counseling

In recent years, tremendous progress has been made in the development of genetic tests to diagnose heritable diseases. You may wish to consult your physician about genetic counseling if any of the following risk factors apply to you:

  • You have a family history of a hereditary disease or of mental retardation of unknown origin.
  • You are a woman older than 35 years of age.
  • You have had a previous child with a chromosomal or other genetic disorder or any birth defects.
  • You have had three or more miscarriages or a stillbirth.

If you have any concerns or questions regarding heritable diseases, ask your physician. If you are considered to be at risk for passing on a hereditary disease to your children, you can receive genetic counseling. A genetic counselor asks you about your personal and family medical history. Blood tests may be necessary to help determine whether you are a carrier of a heritable disorder. You are advised about the chances of transmitting hereditary illness to your offspring. If you are pregnant, the well-being of your fetus can be assessed by several procedures:


  • Ultrasound: High-frequency sound waves are used to produce images of the placenta and fetus. It can detect gross defects, especially of the heart, bones, brain, and spinal cord.
  • Amniocentesis: A small amount of amniotic fluid, the liquid that bathes the baby inside the uterus, is withdrawn and analyzed. Many genetic diseases can be diagnosed prenatally with the use of am-niocentesis.
  • Chorionic Villus Sampling (CVS): A few fetal cells from the chorionic villus, a part of the placenta, are withdrawn and analyzed for the presence of select diseases.
  • Fetoscopy: The fetus is directly observed within the uterus by means of special lenses. During fetoscopy, fetal blood can be sampled. It is rarely used today.
  • Radiography: X-ray films are occasionally obtained because they can depict certain skeletal abnormalities in the fetus.

Remember that the diseases described in this section are rare. Most expectant parents can look forward to the arrival of a healthy baby. If you are pregnant or hope to be and have any worries about the well-being of your child, don't hesitate to address them with your doctor. If your child does have a hereditary disease, however, it's important to confront and accept the realities of this challenge. Keep the lines of communication open within your family, seek out support groups, and avoid bearing all the guilt for your child's disease. Read about coping with a child who has a hereditary illness next.