Non-Syndromic Monogenic Obesity Panel

Summary and Pricing

Test Method

Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
Test Code Test Copy Genes Gene CPT Codes Copy CPT Codes
5033 KSR2 81479,81479 Order Options and Pricing
LEP 81479,81479
LEPR 81406,81479
MC4R 81403,81479
NR0B2 81479,81479
NTRK2 81479,81479
PCSK1 81479,81479
POMC 81479,81479
SH2B1 81479,81479
SIM1 81479,81479
UCP3 81479,81479
Test Code Test Copy Genes Panel CPT Code Gene CPT Codes Copy CPT Code Base Price
5033Genes x (11)81479 81403, 81406, 81479 $640 Order Options and Pricing

Pricing Comments

We are happy to accommodate requests for testing single genes in this panel or a subset of these genes. The price will remain the list price. If desired, free reflex testing to remaining genes on panel is available.

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

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

Obesity is defined as an increase in fat mass that is sufficient to adversely affect health and reduce longevity (Fontaine et al. 2003. PubMed ID: 12517229). Clinically, adults with a body-mass index (BMI) greater than 30 kg/m2 are considered obese. BMI is a multifactorial trait that is usually influenced by multiple genes (Gusev et al. 2014. PubMed ID: 25439723), as well as environmental and lifestyle factors. However, in some cases obesity is inherited by a monogenetic mechanism due to pathogenic variants in a single gene.

The non-syndromic form of monogenic obesity is a group of single gene disorders with obesity as an isolated or predominant feature. The obesity phenotype in these patients is typically severe and early-onset. Infants experience rapid weight gain in the first year of life and reach a BMI > 3 standard deviations above the mean. Associated features include hyperphagia, increased linear growth, delayed puberty, preserved reproductive function, hypocortisolemia and hyperinsulinemia (Albuquerque et al. 2015. PubMed ID: 25749980; Pigeyre et al. 2016. PubMed ID: 27154742)

Genetics

The largest genetic contributors to non-syndromic obesity include genes expressed in the hypothalamus that control energy balance via the leptin-melanocortin signaling pathway (LEP, LEPR, MC4R, POMC, PCSK1, SH2B1, and SIM1). MC4R deficiency is the most prevalent of these disorders, affecting up to 1 in 2,000 individuals (Orphanet). Obesity due to pathogenic MC4R variants is inherited by a semidominant mechanism; the phenotype is severe and fully penetrant in homozygotes or compound heterozygotes, and milder with incomplete penetrance in heterozygotes. POMC and PCSK1 have similar inheritance properties. LEP and LEPR cause autosomal recessive obesity; SH2B1 and SIM1 cause obesity with autosomal dominant inheritance.

Additional genes mediate neuron differentiation and proliferation via tyrosine kinase signaling in the brain, apparently unrelated to the leptin pathway (NTRK2 and KSR2; Pigeyre et al. 2016. PubMed ID: 27154742). NTRK2 and KSR2-related obesity is autosomal dominant.

Finally, UCP3 and NR0B2 are involved in energy utilization in peripheral tissues such as skeletal muscle and liver (Millet et al. 1997. PubMed ID: 9389729; Lu et al. 2000. PubMed ID: 11030331). Pathogenic variants in these genes may cause obesity with autosomal dominant or recessive inheritance.

The genes included on this panel account for all known causes of monogenic non-syndromic obesity due to pathogenic sequence alterations. Pathogenic variants include missense and nonsense changes as well as small and large insertions/deletions (Human Gene Mutation Database). In some cases multifactorial inheritance has been proposed, however, at this time the number of cases is too small to clearly define these variants (Pigeyre et al. 2016. PubMed ID: 27154742).

Clinical Sensitivity - Sequencing with CNV PG-Select

It is difficult to estimate the clinical sensitivity of this test given the significant contribution of environment to obesity. For the MC4R gene alone, the prevalence of pathogenic variants is predicted to be 0.5 - 1% in obese adults and up to 6% in severely obese children (Farooqi and O'Rahilly. 2005. PubMed ID: 15660521; Farooqi et al. 2003. PubMed ID: 12646665). This range in prevalence demonstrates that sensitivity is strongly influenced by the severity and onset of symptoms.

The analytical sensitivity of this test is expected to be high since this Next-Generation sequencing test is designed to detect nearly all clinically relevant sequence and copy number variants in genes that cause monogenic obesity.

Testing Strategy

Additional Sanger sequencing is performed for any regions not captured or with insufficient number of sequence reads.

This panel provides 100% coverage of all coding exons of the genes listed, plus ~10 bases of flanking noncoding DNA. We define coverage as ≥20X NGS reads or Sanger sequencing.

Indications for Test

Candidates for this test are patients with non-syndromic obesity.

Genes

Official Gene Symbol OMIM ID
KSR2 610737
LEP 164160
LEPR 601007
MC4R 155541
NR0B2 604630
NTRK2 600456
PCSK1 162150
POMC 176830
SH2B1 608937
SIM1 603128
UCP3 602044
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Related Test

Name
PGxome®

Citations

  • Albuquerque et al. 2015. PubMed ID: 25749980
  • Farooqi and O'Rahilly. 2005. PubMed ID: 15660521
  • Farooqi et al. 2003. PubMed ID: 12646665
  • Fontaine et al. 2003. PubMed ID: 12517229
  • Gusev et al. 2014. PubMed ID: 25439723
  • Lu et al. 2000. PubMed ID: 11030331
  • Millet et al. 1997. PubMed ID: 9389729
  • Pigeyre et al. 2016. PubMed ID: 27154742

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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