APOL1 Sequencing
Test Mnemonic
APOL1S
CPT Codes
- 81479 - QTY (1)
Performing Laboratory
Knight Diagnostic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 5 mL | Whole blood | EDTA (Lavender) | Refrigerated | Must submit the Molecular Genetics test requisition form with the specimen. Please include detailed clinical information including ethnicity, clinical history, and family history. Send specimen with cold pack. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 10 ug | Extracted DNA | ACD A or B (Yellow) | Refrigerated | 10 ug extracted DNA (from whole blood ONLY) at minimum of 100 ng/uL. Must submit the Molecular Genetics test requisition form with the specimen. Please include detailed clinical information including ethnicity, clinical history, and family history. | |
| 10 ug | Extracted DNA | EDTA (Lavender) | Refrigerated | 10 ug extracted DNA (from whole blood ONLY) at minimum of 100 ng/uL. Must submit the Molecular Genetics test requisition form with the specimen. Please include detailed clinical information including ethnicity, clinical history, and family history. | |
| 5 mL | Whole blood | ACD A or B (Yellow) | Refrigerated | Must submit the Molecular Genetics test requisition form with the specimen. Please include detailed clinical information including ethnicity, clinical history, and family history. Send specimen with cold pack. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 0.2 mL | Absolute minimum with a normal WBC count. Preferred volumes are 5 mL for adult and child, 2 - 3 mL for infant. |
Stability
| Environmental Condition | Description |
|---|---|
| Refrigerated | 7 days |
Days Performed
Varies
Turnaround Time
8 - 16 days
Methodology
| Name | Description |
|---|---|
| Sequencing |
Special Info
Prior to any genetic testing we recommend genetic counseling. MUST submit Molecular Genetics test requisition form with specimen. Ethnicity MUST be included. Include detailed information including ethnicity, clinical history and family history. Package and ship specimen to remain cold, but not frozen. Ship via overnight express (FedEx).
Clinical Info
Compared to individuals without recent African ancestry, African Americans have high rates of kidney disease. Two independent polymorphisms in the APOL1 gene have been shown to be likely associated with the following forms of kidney disease: focal segmental glomerulosclerosis (FSGS) and hypertension-attributed end-stage kidney disease (H-ESKD). The first polymorphism, termed G1, is a two-locus APOL1 polymorphic allele consisting of c.1024A>G; p.Ser342Gly (rs73885319) and c.1152T>G; p.Ile384Met (rs60910145); the second polymorphism, termed G2, is a 6-base pair deletion c.1164_1169delTTATAA (rs71785313). Individuals carrying two risk alleles (G1/G2) have an odds ratio of 7.3 of developing renal disease as compared to individuals carrying neither G1 or G2, while individuals carrying only one risk allele (G1 or G2) have an odds ratio of just 1.26 as compared to individuals carrying neither G1 or G2. A recessive model of inheritance best explains this finding. These APOL1 risk polymorphisms for kidney disease occur in more than 30% of African-American chromosomes while virtually absent in non-African chromosomes. Natural selection provides a plausible explanation as either of the resulting variant proteins provides heightened Trypanosoma lytic activity for heterozygotes with little increased risk for kidney disease. Reasons for Referral: Determination of c.1024A>G, c.1152T>G, and c.1164_1169delTTATAA status: Prior to donation of a kidney, as a limited diagnostic tool, for determination of carrier status. Methodology: Targeted gene sequencing of APOL1 exon 6 in which c.1024A>G, c.1152T>G, and c.1164_1169delTTATAA are embedded. References: 1. S.B. Satko, et al. Kidney Int. suppl 67, (s94), S46 (2005). 2. G. Genovese, et al. Science 329: 841-845 (2010). 3.D. Cohen, et al. Transplantation 92:722-725 (2011).