Family Member Testing
Test code: FMT001 (1 variant), FMT002 (2 variants), FMT003 (3 variants)
Blueprint Genetics provides efficient testing to family members of the probands (index patients) that have previously been or are currently analyzed at Blueprint Genetics. We provide family members with targeted variant testing (1-3 variants) either by Sanger (sequence variants) or qPCR (copy number changes).
Family member testing is performed on relatives to an index case when a positive control is available. This optimizes the testing strategy, guaranteeing efficient and high quality results.
Family Member Testing can be used for:
- Diagnostic testing in affected family members
- Predictive testing in unaffected family members
- Carrier testing in the case of autosomal recessive (AR) disorders
- Segregation of variants of uncertain significance (VUS) where appropriate
Family member testing takes approximately 3-4 weeks.
How to order?
When placing a Family Member Test order, include the Order ID, name and date of birth (DOB) or social security number (SSN) of the index patient previously tested at Blueprint Genetics. If the index patient was not tested at our laboratory, we require detailed information about the variant to be tested [nucleotide change, amino acid change, specific gene transcript (or genomic coordinates)] and a sample from the index patient to act as a positive control. If a positive control sample is not available from the index patient, a sample from another family member may be acceptable. Please contact our Clinical Genetics Support team for further information. It is very important that the positive control sample is from a member of the same family. There is a risk for misinterpreting family member test results if a positive control is not used in the analysis.
Segregation analysis of variants of uncertain significance (VUS)
Segregation of a VUS with disease in a family may allow reclassification of the variant. Typically, we would need to identify the variant in two affected family members and absence of the variant in two unaffected family members if the aim is to reclassify the variant. Every time an FMT result is reported, we take into account all previous samples tested for this specific variant and evaluate it’s classification. Therefore, when testing for the purpose of segregation and potential reclassification, detailed, accurate phenotypic information on all family members participating in the testing and their relationships is required. If FMT testing results in re-classification of the VUS, all patient reports where this variant has been previously identified are updated accordingly, and follow-up Clinical Statements are sent to their ordering health care providers.
If you are interested to learn more about the successful impact of family member testing in resolving VUS, read about the study that re-classified the JPH2 p.(Thr161Lys) variant from VUS to pathogenic.
Number of mutations
Accepted sample types
- EDTA blood, min. 1 ml
- Purified DNA, min. 3μg* in TE buffer or equivalent
- Saliva (Oragene DNA OG-500 kit)
Label the sample tube with your patient’s name, date of birth and the date of sample collection.
Note that we do not accept DNA samples isolated from formalin-fixed paraffin-embedded (FFPE) tissue.