Offered individuals of African,Southeast Asian,& Mediterranean Ancestry.Ifa woman is aware of her status, screening does not need to be repeated. Many US-born women were screened at birth.
Sickle cell: Screen w/ CBC & HbEP in African descent. HbEP allows for detection of HbS & other variants. If positive, partner should undergo carrier screening. Dx: If both partners positive for HbS, refer for genetic counseling to discuss CVS or amniocentesis for diagnostic genetic testing of fetus.
Thal: Screen w/ CBC & MCV in Southeast Asian & Mediterranean descent
Beta-thalassemia: In pts w/ anemia, MCV < 80, & nml iron status (nml ferritin) HbEP should be performed for screening for thal. HbEP shows elevated HbA & HbF for beta-thalassemia. If positive, partner requires screening.
Alpha-thalassemia: HbEP unable to detect alpha-thalassemia, if of Southeast Asian ancestry w/ microcytic anemia, nml iron studies, & nml HbEP offer DNA testing for abn alpha-globin gene. If positive, partner requires screening.
Dx: If both parents are carriers & have described genetic mutations → offer CVS or amniocentesis for fetal genetic testing
CF: Autosomal recessive condition due to >1700 of mutations in CFTR gene.
Routine testing for common mutations offered to all pts (regardless of ethnicity) after appropriate education regarding the implications of testing & results. Detection rate of test related to prevalence in pop. Pts w/ personal Hx or FHx of CF or related conditions should undergo genetic counseling to determine if expanded mut screens are warranted. If pt positive, partner should be screened & consider amniocentesis/CVS.
Fragile X: Most common inherited form of MR. Due to ↑ triplet repeats on FMR1 gene. Offer carrier testing in FHx of fragile X-related disorders, unexplained MR, autism, or premature ovarian failure.Variable penetrance based on number of triplet repeats. Only test for FMR1 triplet rpt is diagnostic test using CVS or amniocentesis for known carriers.
Tay–Sachs: Ashkenazi Jewish,French Canadian,or Cajun descent
Familial dysautonomia or Canavan dz: Ashkenazi Jewish descent
Offer other screening tests (musc dystrophy, Huntington’s) based on FHx