Alport Syndrome, X-linked (COL4A5) Deletion/Duplication
2002394
Ordering Recommendation
This is a second tier test and REQUIRES PERMISSION from  ARUP's Genetic Counselor (800-242-2787, x2141) before ordering. Preferred initial test is the sequencing and deletion/duplication test.
Mnemonic
ALPORT DD
Methodology
Polymerase Chain Reaction/Multiplex Ligation-dependent Probe Amplification
Performed
Varies
Reported
Within 14 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) Deletion/Duplication
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:
Approximately 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:
Pathogenic type 4 collagen alpha chain 5 (COL4A5) mutations.
Clinical Sensitivity:
Approximately 10 percent of X-linked Alport syndrome is due to large COL4A5 gene deletions or duplications.
Methodology:
Multiplex ligation-dependent probe amplification (MLPA) to detect large COL4A5 coding region deletions/duplications.
Analytical Sensitivity & Specificity:
99 percent.
Limitations:
Diagnostic errors can occur due to rare sequence variations. Breakpoints for large deletions/duplications will not be determined. COL4A5 base pair substitutions, small deletions/duplications, deep intronic, and regulatory region mutations will not be detected. Mutations in genes, other than COL4A5, are not evalutated.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS  
Note
 
CPT Code(s)
81407
Components
Component Test Code*Component Chart Name
2002395Alport Syndrome (COL4A5) Del/Dup Interp
2002396ALPORT DD 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 syndrome deletion/duplication assay
  • X-linked Alport syndrome molecular testing