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Proximal Renal Tubular Acidosis with Ocular Abnormalities via the SLC4A4 Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
11685 SLC4A4 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11685SLC4A481479 81479,81479 $890 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing backbone).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing backbone).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Turnaround Time

3 weeks on average for standard orders or 2 weeks on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.


Genetic Counselors


  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Proximal renal tubular acidosis (pRTA) results from an impairment of bicarbonate reabsorption in the renal proximal tubules. Permanent isolated pRTA usually occurs with ocular abnormalities (Igarashi et al. 1999). Clinical features include severe hyperchloremic acidosis, a decreased tubular capacity for bicarbonate reabsorption (about half normal), growth retardation, mental retardation, nystagmus, cataract, corneal opacities, glaucoma, and defects in the enamel of permanent teeth. Age of onset is typically in childhood or adolescence.


Proximal renal tubular acidosis with ocular abnormalities is an autosomal recessive disorder caused by defects in the SLC4A4 gene (Igarashi et al. 1999; Horita et al. 2005). The SLC4A4 gene (22 coding exons) encodes a sodium bicarbonate cotransporter (NBC) involved in the regulation of bicarbonate secretion and absorption and intracellular pH. To date, documented genetic defects of SLC4A4 include missense, nonsense, and small indels (Human Gene Mutation Database). Large deletions/duplications have not been reported.

Clinical Sensitivity - Sequencing with CNV PGxome

Detection rate of pathogenic variants in the SLC4A4 gene in a large cohort of patients with proximal renal tubular acidosis with ocular abnormalities is unknown in the literature because to date only a limited number of cases have been reported. The reported pathogenic variants are all detectable by sequencing.

Testing Strategy

This test provides full coverage of all coding exons of the SLC4A4 gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

Candidates for this test are patients with proximal renal tubular acidosis with ocular abnormalities. Testing is also indicated for family members of patients who have known pathogenic variants in the SLC4A4 gene. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in SLC4A4.


Official Gene Symbol OMIM ID
SLC4A4 603345
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


  • Horita S. et al. 2005. Journal of the American Society of Nephrology. 16: 2270-8. PubMed ID: 15930088
  • Human Gene Mutation Database (Bio-base).
  • Igarashi T. et al. 1999. Nature Genetics. 23: 264-6. PubMed ID: 10545938


Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page

Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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View Ordering Instructions

1) Select Test Method (Backbone)

1) Select Test Type

2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
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