Glycine Encephalopathy via the GCSH Gene
Summary and Pricing 
Test Method
Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture ProbesTest Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
---|---|---|---|---|---|
5491 | GCSH | 81479 | 81479,81479 | $990 | Order Options and Pricing |
Pricing Comments
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.
An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.
Testing run on PG-Select capture probes does not include exome-wide CNV analysis. Reflex is available to PGxome or an exome-based panel, or you can use this gene list to create a custom panel (click here).
Click here for costs to reflex to whole PGxome.
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.
Clinical Features and Genetics 
Clinical Features
Glycine encephalopathy, also known as nonketotic hyperglycinemia (NKH), is an inborn error of glycine metabolism caused by defects in the glycine cleavage multi-enzyme system (GCS) (Hamosh et al. 2002. PubMed ID: 20301531). Affected children have a large accumulation of glycine in the body resulting in various neurological symptoms. The majority of patients with glycine encephalopathy present in the neonatal period, while some patients can develop the disease in infancy. Regardless of age at onset, 20% of all affected children present with atypical, less severe phenotypes.
Affected neonates develop severe symptoms including progressive lethargy, hypotonia, and myoclonic jerks leading to apnea and often death. Surviving infants have hypotonia, profound intellectual disability, developmental delay and intractable seizures. The atypical form has disease onset from late infancy to adulthood and the clinical outcomes range from milder features to rapidly progressive severe disease.
Genetics
Glycine encephalopathy is an autosomal recessive disorder. GLDC, AMT and GCSH are the three known genes associated with the disease (Kure et al. 2006. PubMed ID: 16450403). These three genes encode the P, T and H proteins of the glycine cleavage multi-enzyme system (GCS), respectively.
Genetic defects of GCSH (5 coding exons) are an extremely rare cause of glycine encephalopathy. To date, only one conclusively pathogenic GCSH variant affecting splicing has been documented for a transient form of glycine encephalopathy (Human Gene Mutation Database).
Clinical Sensitivity - Sequencing with CNV PG-Select
Genetic defects of GCSH are an extremely rare cause of glycine encephalopathy. In a study of 69 families with glycine encephalopathy, no pathogenic GCSH variants were found (Kure et al. 2006. PubMed ID: 16450403).
Testing Strategy
This test provides full coverage of all coding exons of the GCSH gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.
Indications for Test
Candidates for this test are patients with glycine encephalopathy or family members. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in GCSH.
Candidates for this test are patients with glycine encephalopathy or family members. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in GCSH.
Gene
Official Gene Symbol | OMIM ID |
---|---|
GCSH | 238330 |
Inheritance | Abbreviation |
---|---|
Autosomal Dominant | AD |
Autosomal Recessive | AR |
X-Linked | XL |
Mitochondrial | MT |
Disease
Name | Inheritance | OMIM ID |
---|---|---|
Glycine Encephalopathy | AR | 605899 |
Related Tests
Name |
---|
AMT-Related Glycine Encephalopathy via the AMT Gene |
GLDC-Related Glycine Encephalopathy via the GLDC Gene |
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.
- 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
ORDER OPTIONS
View Ordering Instructions1) 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.