When we receive multiple samples from members of the same family, initially, we only screen one person for genetic variations. We call this person the "proband". A proband is usually the first affected individual in a family who brings a genetic disorder to the attention of the medical community (Source: Talking Glossary of Genetic Terms). This saves time and resources and there is little point in screening other family members until we know exactly what to look for.
When a positive finding (a disease-causing variation) is discovered in the first family member, we then screen the parents for the same variation(s). Parental samples are considered part of the child’s test for autosomal recessive diseases only (LCA for example). Because parents are screened at no charge, a separate report will not be issued. Instead, a notation regarding their test results will be made on their child's report. Note: parental samples are not needed to confirm findings for autosomal dominant diseases. For this reason, parental samples are not included in the proband’s test. Should an affected parent decide to submit his/her own sample for genetic testing, there is a fee for this service and a separate report is issued.
If no disease-causing variations are discovered in the proband than there is no benefit to test the additional family members. Testing on their samples is then canceled, but samples will be banked for possible future study if enrolled in our research cohort.
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