Your Baby’s Screening Carrier Identification

Occasionally, when a baby’s newborn screen is out-of-range for conditions like cystic fibrosis or sickle cell anemia, follow-up testing reveals that he or she is a carrier of the condition.

Most of the conditions identified through newborn screening are autosomal recessive genetic conditions. Babies with autosomal recessive conditions inherited two non-working copies of a particular gene – one from their mother and one from their father. If a child only inherits one non-working copy of the gene, he or she is considered a “carrier” of the condition. 

Is my child really healthy?

In recessive conditions, a single non-working gene is not enough to cause the serious and life-threatening symptoms that are typically associated with a condition. In fact, most carriers are healthy and do not even know they have a non-working copy of the gene.  

What does this mean for my family?

Children inherit pairs of genes from their parents – one from their father and one from their mother. Therefore, if a child has a non-working copy of a gene, they most likely inherited it from one of their parents. This can have implications for the entire family.  

When a child is identified as a carrier of a genetic condition, it is possible that one or both parents are carriers of the condition, as well. Therefore, the parents may want to undergo genetic testing and counseling to determine their own carrier status, especially if they plan on having more children in the future. When one parent is a carrier of the condition and the other parent has two working copies of the gene:

  • There is a 1 in 2 chance (50%) of having a child with 2 working genes. 
  • There is a 1 in 2 chance (50%) of having a child who is a carrier (1 working copy and 1 non-working copy of the gene).

Recessive genetic conditions

When both parents are carriers of a recessive genetic condition:

  • There is a 1 in 4 chance (25%) of having a child affected by a recessive condition.
  • There is a 1 in 4 chance (25%) of having a child with 2 working genes.
  • There is a 1 in 2 chance (50%) of having a child who is a carrier (1 working copy and 1 non-working copy of the gene).

Depending on the carrier status of the parents, siblings may have inherited a non-working copy of the gene, as well. They may wish to pursue carrier testing when they reach reproductive age to determine their own chance of having a child with a genetic condition.