Nephrogenic Diabetes Insipidus (NDI) and Nephrogenic Syndrome of Inappropriate Antidiuresis (NSIAD) via the AVPR2 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
8907 AVPR2 81404 81404,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8907AVPR281404 81404, 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. If the Sanger option is selected, CNV detection may be ordered through Test #600.

A 25% additional charge will be applied to STAT orders. View STAT turnaround times here.

For Reflex to PGxome pricing click here.

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

For Sanger Sequencing click here.

Targeted Testing

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

Turnaround Time

18 days on average

EMAIL CONTACTS

Genetic Counselors

Geneticist

Clinical Features and Genetics

Clinical Features

Nephrogenic Diabetes Insipidus (NDI) is a kidney disorder characterized by polyuria (too much urine) and polydipsia (excessive thirst), which results from an insensitivity to vasopressin (also called antidiuretic hormone, ADH), a hormone that regulates the kidneys to retain water.

Inherited NDI patients usually display early onset (< 1 year old), poor feeding, failure to thrive, fever and short stature, and are prone to severe dehydration trigged by illness, hot environments and water depletion. Inactivating mutations in the arginine vasopressin receptor gene (AVPR2) were shown to cause X-linked recessive NDI (OMIM#304800), which accounts for ~ 90% of inherited NDI, whereas activating mutations in the AVPR2 gene cause nephrogenic syndrome of inappropriate antidiuresis (NSIAD) (OMIM#300539), a rare disorder which can cause brain swelling and other serious complications due to low levels of salt in the blood (hyponatremia) (Knoers, GeneReview 2012; Bichet et al. Prog Mol Biol Transl Sci, 89:15-29, 2009). Recent data suggests that ~25% of females who are heterozygous carriers for AVPR2 causative gene mutations have NDI symptoms (Sasaki et al., 2012).

Genetics

Inherited NDI can be caused by mutations in the AVPR2 and AQP2 genes. AVPR2 (OMIM#300538) encodes arginine vasopressin receptor 2 (V2R), a member of G protein superfamily predominantly expressed in the kidney collecting ducts. Coupled with arginine vasopressin (AVP), V2R activates a series of reactions to regulate transepithelium water permeability in renal collecting tubes. This increases water reabsorption from urine and maintains body’s water homeostasis. To date, more than 200 causative mutations have been reported throughout the gene including missense (~50%), truncating, splice mutations, or large deletions encompassing the entire AVPR2 gene (Anesi et al, 2012). Missense mutations R137C or R137L were linked to NSIAD, while missense mutation R137H was found in classic NDI (Bichet et al, 2009).

Clinical Sensitivity - Sequencing with CNV PGxome

AVPR2 causative gene mutations can be detected by sequencing in about 95% of patients with clinically diagnosed X-linked Nephrogenic diabetes insipidus (Knoers, GeneReview 2012).

Approximately 8% of reported AVPR2 pathogenic variants are large deletions/duplications, which cannot be detected by Sanger Sequencing (Human Gene Mutation Database).

Testing Strategy

This test provides full coverage of all coding exons of the AVPR2 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.

Since this test is performed using exome capture probes, a reflex to any of our exome based tests is available (PGxome, PGxome Custom Panels).

Indications for Test

Candidates for this test are patients with symptoms consistent with X-linked Nephrogenic Diabetes Insipidus (NDI), Nephrogenic Syndrome of Inappropriate Antidiuresis (NSIAD) and the family members of patients who have known AVPR2 mutations.

Gene

Official Gene Symbol OMIM ID
AVPR2 300538
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Citations

Ordering/Specimens

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.

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

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ORDER OPTIONS

View Ordering Instructions

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.

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