Pan-Ethnic Carrier Screening: Information for Health Professionals

DNA from a blood or saliva sample is analyzed for hundreds of different mutations, each of which is associated with a particular disease.  For some conditions, a single mutation is assessed, whereas for others, more than a dozen mutations are analyzed.  Carriers of a particular disorder are identified when one copy of a mutation for that disease is detected.

What are the benefits of enhanced carrier screening?

• A single small sample can be tested for cystic fibrosis, fragile X, and spinal muscular atrophy carrier status, in addition to dozens of other, rarer, autosomal recessive conditions.
• Individuals of Ashkenazi Jewish ancestry can be tested, economically, for over a dozen genetic disorders.
• For persons of various ethnic minorities, carrier status can be determined for disorders prevalent in their communities.

Quite frankly, there is.  When screening for such a large number of rare diseases, many people will be identified as carriers for one, and sometimes two or three diseases.  Usually, their reproductive partner will screen negative for the same disease(s).  However, in some cases, there will still be a significant "residual risk" for having an affected child, because carrier screening may be considerably less than 100% sensitive.  More sensitive methods of carrier screening for individual diseases are available, but they are often quite expensive.

Important points to keep in mind:

• Prenatal diagnosis is available when both parents are identified as carriers for an autosomal recessive disorder, and when a woman is found to be a fragile X carrier.
• The cost of enhanced carrier screening may be higher than routine, more limited screening.  However, in some cases, such as for couples of Ashkenazi ancestry, pan-ethnic screening can actually be considerably less expensive.
• Pan-ethnic screening is most useful for couples who are of various ethnic minorities, when diseases prevalent in those ethnic groups are included on a particular laboratory's panel.
• Reports for such extensive testing tend to be very long, but most laboratories highlight the abnormal results prominently on the first page.

Enhanced screening is a convenient and economical option, particularly for patients who have not had prior carrier screening, since it includes screening recommended for Caucasian couples (cystic fibrosis) and carrier screening that some professional societies have recommended (fragile X and spinal muscular atrophy), as well as the extended disease panel.  Each laboratory performing pan-ethnic screening has slightly different disease and mutation panels.  Genetic consultation is helpful when one or both members of a couple have abnormal screening results.
 
 

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