Ordering Recommendation

Acceptable genetic test for the detection of variants causing X-linked Alport syndrome.

Mnemonic
ALPORT FGS
Methodology

Polymerase Chain Reaction/Sequencing

Performed

Varies

Reported

21-28 days

New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA) or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval
Interpretive Data

Background Information for Alport Syndrome, X-linked (COL4A5) Sequencing:
Characteristics:
Progressive renal and cochlear disease with 30-40 percent incidence of ocular involvement; 60 percent of males reach end stage renal disease by age 30 and 85 percent have sensorineural deafness by age 40.
Incidence: Estimated to be between 1 in 5,000 to 1 in 50,000 live births.
Inheritance: X-linked recessive; de novo mutations in 10-15 percent of affected males.
Penetrance: Variable depending on mutation and sex..
Cause: Type 4 collagen (COL4A5) alpha chain mutations.
Clinical Sensitivity: Greater than 80 percent for X-linked Alport syndrome.
Methodology: Bidirectional sequencing of the entire COL4A5 coding region and intron-exon boundaries.
Analytical Sensitivity & Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region and deep intronic mutations will not be detected. Large deletions/duplications will not be detected in females. Mutations in genes other than COL4A5 are not evaluated.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81408

Components
Component Test Code* Component Chart Name LOINC
0051787 Alport Syndrome (COL4A5) Sequencing
2001337 ALPORT FGS Specimen
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Alport syndromesequencing assay
  • X-linked Alport syndrome molecular testing
Alport Syndrome, X-linked (COL4A5) Sequencing