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Alport Syndrome

Alport syndrome (AS) is a progressive glomerulonephritis associated with sensorineural hearing loss with a prevalence of about 1 in 50,000 live births. X-linked Alport syndrome usually manifests in affected males with microscopic hematuria and progressive sensorineural hearing loss during childhood or adolescence. Later, patients develop proteinuria andprogressive renal failure, which eventually leads to end-stage renal […]

Alport syndrome (AS) is a progressive glomerulonephritis associated with sensorineural hearing loss with a prevalence of about 1 in 50,000 live births. X-linked Alport syndrome usually manifests in affected males with microscopic hematuria and progressive sensorineural hearing loss during childhood or adolescence. Later, patients develop proteinuria andprogressive renal failure, which eventually leads to end-stage renal disease in their 30s and 40s. Ocular symptoms are also common and may include maculopathy, posterior polymorphous dystrophy, and recurrent corneal erosion. Anterior lenticonus is considered to be virtually pathognomonic for Alport syndrome. X-linked Alport syndrome is semi-dominant and often manifests in female carriers. Approximately 90% of female carriers have microscopic hematuria, which can lead to renal failure later in life. Hearing loss is less frequent in female carriers, with a later age of onset.

Alport syndrome with diffuse leiomyomatosis is a contiguous gene deletion syndrome. The submicroscopic genomic deletions involve the COL4A5 gene and parts of the adjacent COL4A6 gene. This disorder is characterized by features of Alport syndrome and by leiomyomatosis of the esophagus and tracheobronchial tree. It manifests in late childhood and can include dysphagia, postprandial vomiting, epigastric pain, recurrent bronchitis, dyspnea, cough, and stridor. Affected females may also have genital leiomyomas.

Alport syndrome associated with mental retardation, midface hypoplasia and elliptocytosis is another contiguous gene deletion syndrome involving COL4A5 and FACL4, which encodes a long-chain acyl-CoA synthetase

Tests Available

COL4A5 Gene Sequencing

FORMS AND DOCUMENTS

TEST DETAILS

Genes:
COL4A5
Clinical Utility:
  • Confirmation of a clinical diagnosis
  • Differentiation between X-linked and autosomal recessive or dominant forms of the disease
  • Carrier detection in female relatives of an affected male
  • Prenatal diagnosis in at-risk pregnancies
Lab Method:
Capillary Sequencing

ORDERING

Test Code:
281
Turnaround Time:
4 weeks
Preferred Specimen:
2-5 mL Blood - Lavender Top Tube
Alternative Specimen:
Oral Rinse (30-40 mL), Buccal Brushes

BILLING

CPT Codes:
81408x1
New York Approved:
No
ABN Required:
Yes
Billing Information:
View Billing Policy
* For ICD9 to ICD10 conversion please follow this link https://www.aapc.com/icd-10/codes/
ICD-9 Codes:
  • 389.1: Sensorineural hearing loss, Perceptive hearing loss or deafness
  • 583.9: With unspecified pathological lesion in kidney Glomerulitis NOS, Glomerulonephritis NOS, Nephritis NOS, Nephropathy NOS
  • 743.8: Other specified anomalies of eye
  • 585.9: Chronic kidney disease, unspecified Chronic renal disease Chronic renal failure NOS, Chronic renal insufficiency
* For price inquiries please email zebras@genedx.com

REFERENCES

  1. Arrondel C et al (2004) Kidney Int 65:2030-2040
  2. Gross O et al (2002). Nephrol Dial Transplant 17:1218-1227
  3. Hertz JM et al (2001). Human Mutation 18:141-148
  4. Kashtan C (1999). Medicine (Baltimore) 78:338-360
  5. Kashtan C (Updated 01-08-2007) Collagen IV-Related Nephropathies (Alport Syndrome and Thin Basement Membrane Nephropathy)
  6. Martin, P et al (1998). J Am Soc Nephrol 9:2291-2301
  7. Plant K et al (1999). Human Mutation 13:124-132
  8. Vetrie et al (1992) Genomics 14(3):624-633

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