January 30, 2012
The story regarding Republican presidential candidate Rick Santorum’s daughter, brings the subject of genetics into the forefront. Santorum’s 3-year-old daughter, Bella, has Trisomy 18, which is an abnormal disorder where some cells do not contain 2 complete sets of 23 chromosomes. It is almost always fatal and most affected babies die at birth or shortly thereafter. Bella, by some schools of thought, might be considered a miracle.
The diagnosis of a genetic disorder such as Trisomy 18, usually begins with either a screening blood test such as quad screen, or a routine ultrasound after 17 to 18 weeks. The technician or physician might note a fetus that has a clenched fist or unusual feet called Rockerbottom feet. These signs are called the Edward’s syndrome. Other ultrasound findings that suggest genetic abnormalities include polyhydramnios or excessive amniotic fluid, a “double-bubble” sign indicating a condition called duodenal atresia that is associated with Down syndrome as well as heart problems. Also, most fetuses with Down syndrome also have congenital heart problems.
If a suspicious finding is detected on an ultrasound, the technician should report it to your physician immediately for further evaluation and consultation. These consultations should include a referral to a geneticist. The geneticist will take a complete family history from both you and the father of your baby and might suggest obtaining an amniocentesis procedure to obtain fetal cells for confirmation of the disorder. All amniocentesis procedures require written consent because there is a 1 percent risk of rupturing the membranes during the procedure. There are 2 schools of thought regarding genetic screening: one school says why bother? There’s nothing that can be done. The other says it is good to know in advance so that the mother can make critical decisions regarding the continuation of the pregnancy.
Genetic counselors can identify other potential problems such as hemophilia and color blindness which are called x-linked disorders. These conditions are carried on the genes of females but only expressed or affected by males.
Genetics is an evolving field that continues to play an important role in obstetrics and pediatrics. All pregnant women should be encouraged to fully utilize their services as needed.
Remember, a healthy pregnancy doesn’t just happen. It takes a smart mother who knows what to do.