218 Obstetrics and Gynecology Board Review •••
❍ What are the potential risks associated with selective serotonin uptake inhibitor (SSRI) use during
pregnancy?
Possible increased risk of congenital cardiac anomalies with first trimester exposure to Paxil. Exposure to SSRIs in
late pregnancy can result in transient neonatal complications including persistent pulmonary hypertension.
❍ A patient reports that she and her partner are of Ashkenazi Jewish ancestry. Which screening tests would
you offer and what inheritance pattern would you discuss with them?
ACOG recommends screening for Tay-Sachs disease, Canavan disease, familial dysautonomia, and cystic fibrosis
(CF). Additionally, this couple is at increased risk of Gaucher disease, Niemann-Pick disease, Fanconi anemia,
Bloom syndrome, Mucolipidosis IV, glycogen storage disease 1A, Maple syrup urine disease, dihydrolipoamide
dehydrogenase deficiency, familial hyperinsulinism, Usher Syndrome type IF, Usher syndrome type III, and
nemaline myopathy. These conditions all have an autosomal recessive inheritance pattern.
❍ Besides the Ashkenazi Jewish population, what other ethnic backgrounds are at increased risk of Tay-Sach
disease?
French Canadian (1:30), Louisiana Cajun (1:30), and Celtic/Irish (1:50).
❍ Your patient is of Irish and German descent. What is her risk to be a carrier of CF? If she screens negative on
the standard CF panel (23 mutations), what is her residual risk to be a CF carrier?
1:25; 1:208.
❍ For which ethnic group is the detection rate for CF screening the lowest?
Asian.
❍ An African American couple reports that they have a daughter with CF. Your patient’s prenatal CF carrier
screen is negative. What explanation can you give this couple?
The standard CF panel looks for 23 mutations and has a 69% detection rate in the African American population
(as compared with a 90% detection rate in the Caucasian population). There are over 1000 mutations in the
CFTR gene; thus the patient may carry a mutation not screened for in the standard panel.
❍ A patient of yours has sickle cell trait and her partner’s hemoglobinopathy evaluation revealed probable
b-thalassemia trait. What are the risks to their offspring?
25% carrier of hemoglobin S, 25% carrier of β-thalassemia, 25% noncarrier/unaffected, and 25% affected with
sickle β-thalassemia.
❍ A patient’s a-thalassemia DNA report shows she is a cis carrier of a-thalassemia; her husband is found to
have one a-thalassemia mutation. What condition is their offspring at risk of?
Hemoglobin H disease (–/a-)
❍ A pregnant patient with achondroplasia is under your care. Her husband is of typical stature. What is the
inheritance pattern of this condition? What is the chance for this couple to have a child with achondroplasia?
Autosomal dominant; 50%.