Molecular Genetics in Prenatal Diagnosis

Question 1

What are the indications for molecular testing in the prenatal setting?

Answer 1

• family history of a known familial variant
• parent(s) known carriers of a genetic disease
• ultrasound anomalies

Question 2

What are typical indications for molecular genetic testing in prenatal related to family history?

Answer 2

1. parent affected with a genetic condition
   - typically autosomal dominant disease
2. parent(s) with a previous affected child.
   - may be de novo dominant (1% or less risk of recurrence due to possibility of gonadal mosaicism)

Question 3

What are typical conditions that would warrant molecular prenatal genetic testing when parent(s) are carriers of genetic disease?

Answer 3

Usually, these conditions are autosomal recessive or X-linked.

Question 4

When parent(s) are carriers of a gentic disorder, if molecular testing is ordered, what are the requirements the lab will ahve for testing?

Answer 4

Labs often require blood samples from each carrier parent as carrier control samples.
- it’s not enough to just send a copy of their carrier screening results along with a prenatal sample.
- Lab will want a sample from each carrier parent so that they know exactly what they are looking for and that they are able to detect it