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Newborn Screening Ontario
Screening Results

Health Expectations for Carriers

Carriers for Sickle Cell Disease are not more likely to get sick than any other child. They do not need special medical care. Being a carrier of a hemoglobinopathy does not affect life expectancy. Carriers for some hemoglobin diseases need to be aware of a few things, listed below.

Carriers of Sickle Cell Disease (HbS)

Most carriers of Sickle Cell Disease do not have health problems from being a carrier. They will not develop Sickle Cell Disease later in life. Rarely, carriers can have some health issues, most of which are minor, and do not occur in childhood. These include:

  • Blood and/or protein in the urine (Hematuria and/or Proteinuria)
    • Typically only seen under the microscope during a urine test (urinalysis).
    • Rarely a teenager or adult may be able to see blood in the urine, or protein in the urine that causes symptoms.
    • Before concluding that either of these are related to being a carrier for Sickle Cell Disease, other reasons need to be ruled out.
  • Loss of the ability of the kidneys to concentrate the urine (Hyposthenuria)
    • As adults, the kidney may lose the ability to concentrate urine to the best of its ability. This rarely causes any health issues.
    • Staying hydrated is encouraged.
  • Urinary Tract Infection
    • Adult women who are carriers of Sickle Cell Disease have more urinary tract infections, especially during pregnancy, compared to the other people.
    • Men do not seem to have an increased frequency of urinary tract infections.
  • Increase in pressure inside the eye following injury (Traumatic Hyphema)
    • Any carrier of Sickle Cell Disease who gets injured in the eye (for example balls, rocks, pucks) should see an eye doctor right away because of the risk of damage to the eye.
  • Chronic Kidney Disease
    • As adults, carriers of Sickle Cell Disease have a slightly higher chance of developing kidney disease compared to other people.
    • The chances of developing end-stage kidney disease does not seem to be higher.
  • Exertional Heat Illness
    • There are a number of case reports stating that carriers of Sickle Cell Disease have an increased chance to develop a condition called ‘exertional heat illness’. This is something that can happen after a person participates in a grueling activity (for example, professional sports, military training, mountain climbing) under extreme conditions (for example, in very hot weather, at very high altitude, while dehydrated). Exertional heat illness can cause muscle damage, collapse and very rarely death.
    • Recent studies have questioned whether or not being a carrier of HbS causes an increased risk for exertional heat illness. Additional research has shown that:
      • Most carriers of Sickle Cell Disease do not develop exertional heat illness even when doing the types of activities listed above
      • This condition can also occur in individuals who are not carriers of HbS
      • Proper hydration and rest breaks during exercise can successfully prevent exertional heat illness in both carriers and non-carriers
    • The exact relationship between being a carrier of Sickle Cell Disease and the chance of developing exertional heat illness is still not completely determined and is an area of ongoing research.

Carriers of Hemoglobin C (HbC)

Rarely carriers can have slightly smaller red blood cells (mild microcytosis) and borderline low hemoglobin levels.

Carriers of Hemoglobin E (HbE)

Rarely carriers can have slightly smaller red blood cells (mild microcytosis).

Carriers of an Unspecified Hemoglobin Variant

An unspecified hemoglobin variant is unlikely to cause any health issues, however genetic testing is needed to provide more specific information.