Carrier Screening Flashcards
What screening does ACOG recommend for in all people pregnant or planning to become pregnant
SMA, CF, complete blood count
What screening does ACOG recommend for specific ethnic groups
Hemoglobinopathies (Africa , Mediterranean, middle eastern, West Indian, or if abnormal CBC)
What are CF carrier rates for ashkenazi Jewish ancestry, Caucasian, Hispanic white, African American, Asian American
1/24, 1/25, 1/58, 1/61, 1/94
What is the most common cause of SMA
Deletion of exon seven of SMN1
What determines the severity of SMA
The number of SMN2 genes
What is carrier frequency of SMA
1/40-1/60
What mutation causes sickle cell disease
HbSS c.20A>T homozygous
What conditions does ACOG recommend testing individuals of ashkenazi Jewish descent for
Canavan disease, cystic fibrosis, familial dysautonomia, tay sachs
Who is fragile x screening recommended for
Based on family history, ID suggestive, primary ovarian insufficiency before age 40
What are the typical, premutation, & full mutation numbers of repeats for fragile x
Less than 45, 55-200, more than. 200
What is the carrier frequency of tay sachs for individuals of ashkenazi Jewish decent
1 in 29
What populations have a higher carrier frequency of tay sachs
French Canadian, Cajun descent, Ashkenazi jewish
What were some ACMG recommendations regarding carrier screening tests overall
Should just be called carrier screening, a tier system should be utilized, should be ethnic & population neutral & more inclusive of diverse populations, screening can be offered to partners simultaneously
What tier/ group of conditions does ACMG recommend screening for in all pregnant people or those planning to become pregnant
Tier 3: conditions with carrier frequency greater than 1 in 200, including x linked conditions
When does ACMG recommend consideration of tier 4 carrier screening
Known or possible consanguineous relationship, when warranted by personal or family history
What are reasons to move from ethnic based to expanded carrier screening
Patients increasingly have multiple ethnic backgrounds, may not know their ethnic background, may not want to share ethnicity or ancestry, & conditions can still occur outside of high risk populations
What should be true about conditions offered on carrier screening per ACOG
Carrier frequency >1 in 100, well defined phenotype, detrimental effect on quality of life, causes physical or cognitive impairment, requires surgical or medical intervention, has early onset, conditions that can be diagnosed prenatally, have delivery managements or interventions that can improve outcomes
What are some concerns regarding expanded carrier screening
May be screening for phenotypically mild or variable conditions, too much information can be overwhelming to some patients, no consensus on what conditions should be included
