Congenital Bile Acid Synthesis Defect Type 2 via the AKR1D1 Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesPrice Test CPT CodeGene CPT Codes Copy CPT Codes
11081 AKR1D1$890 8147981479,81479 Add to Order

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.

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

Congenital bile acid synthesis defect type 2 (CBAS2) is a progressive liver disease of neonatal onset characterized by cholestasis (Lemonde et al. 2003; Ueki et al. 2009). Due to impaired bile acid synthesis, within the first weeks of life, affected infants start to present with malabsorption of lipids and lipid-soluble vitamins from the gastrointestinal tract. Clinical features include failure to thrive, jaundice, steatorrhea, hepatomegaly, cirrhosis, rickets and splenomegaly.

Genetics

Recessive AKR1D1 pathogenic variants cause congenital bile acid synthesis defect type 2 (Lemonde et al. 2003; Ueki et al. 2009). The AKR1D1 gene (9 coding exons; also known as SRD5B1) encodes the steroid 5-beta-reductase, which is responsible for the catalysis of the 5-beta-reduction of bile acid intermediates and steroid hormones carrying a delta(4)-3-one structure. Genetic defects of AKR1D1 found to date include missense, nonsense, and small deletions (Human Gene Mutation Database). No large deletions and duplications have been reported.

Testing Strategy

This test provides full coverage of all coding exons of the AKR1D1 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).

Clinical Sensitivity - Sequencing with CNV

Detection rate of pathogenic variants in the AKR1D1 gene in a large cohort of patients with congenital bile acid synthesis defect type 2 is unknown in the literature because only a limited number of cases have been reported. However, mutation detection rate is expected to be high if patients are strongly indicated both clinically and biochemically.

Indications for Test

Candidates for this test are patients with congenital bile acid synthesis defect type 2. Testing is also indicated for family members of patients who have known AKR1D1 mutations. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in AKR1D1.

Gene

Official Gene Symbol OMIM ID
AKR1D1 604741
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Bile Acid Synthesis Defect, Congenital, 2 AR 235555

Citations

  • Human Gene Mutation Database (Bio-base).
  • Lemonde et al. 2003. PubMed ID: 12970144
  • Ueki I. et al. 2009. Journal of Gastroenterology and Hepatology. 24: 776-85. PubMed ID: 19175828

Ordering/Specimens

Ordering Options

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.

Specimen Types

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