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Temtamy Syndrome via the C12orf57 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
13049 C12orf57 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
13049C12orf5781479 81479(x2) $890 Order Options and Pricing

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).

Turnaround Time

18 days on average for standard orders or 13 days 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.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Erin Sybouts, PhD

Clinical Features and Genetics

Clinical Features

Temtamy syndrome is a congenital neurological disorder characterized by intellectual disability and congenital anomalies. Major clinical features include global developmental delay and intellectual disability (100%), absent speech (74.5%), seizures (73.7%), autistic behavior (72.7%), generalized hypotonia (71.9%), facial dysmorphism (66.1%), and abnormal (hypoplasia, agenesis, dysplasia, or thick) corpus callosum (61.8%). Minor features include ocular anomalies (46.4%), delayed speech (37.5%), spasticity (35.1%), atrial septal defect (30.4%), abnormal thalamic size (38.5%), abnormal septum pellucidum (37.3%), abnormal white matter (37.3%), ventriculomegaly (35.3%), and abnormal anterior commissure (21.2%). Less common clinical features include microphthalmia (14.3%), coloboma (14.5%), ventricular septal defect (10.0%), and pulmonic stenosis (11.1%) (Alrakaf et al. 2018. PubMed ID: 29383837; Wang et al. 2020. PubMed ID: 31853307). The clinical features of Temtamy syndrome show considerable variability, even among affected family members (Li et al. 2007. PubMed ID: 17632789; Salih et al. 2013. PubMed ID: 23633300; Platzer et al. 2014. PubMed ID: 24798461).

Temtamy syndrome is extremely rare, with an estimated incidence of less than one in a million individuals worldwide. However, the identification of a founder variant in the causative gene, C12orf57, in 1.5% of patients with intellectual disability in a large Arab cohort indicates it is the most common cause of intellectual disability in Saudi Arabia (Anazi et al. 2017. PubMed ID: 27431290; Monies et al. 2017. PubMed ID: 28600779; Alrakaf et al. 2018. PubMed ID: 29383837).

Advantages of molecular testing for Temtamy syndrome via C12orf57 sequencing include molecular confirmation of diagnosis, differential diagnosis, and reproductive planning.

Genetics

Temtamy syndrome is an autosomal recessive disorder caused by biallelic pathogenic variants in the C12orf57 gene. The majority of causative variants in C12orf57 are loss of function variants, including start loss, splicing donor/acceptor variants, premature protein termination, and frameshift variants (Alrakaf et al. 2018. PubMed ID: 29383837). As mentioned above, a founder variant, C12orf57 c.1A>G (p.Met1?), has been identified in individuals of Arabic descent. It is the most common reported pathogenic variant in C12orf57 (Salih et al. 2013. PubMed ID: 23633300; Akizu et al. 2013. PubMed ID: 23453666; Zahrani et al. 2013. PubMed ID: 23453665; Alrakaf et al. 2018. PubMed ID: 29383837). In gnomAD, the maximum minor allele frequency for the C12orf57 c.1A>G variant is 0.006% (Genome Aggregation Database).

C12orf57 has been cited as a nonessential gene for growth of human tissue culture cells (Online Gene Essentiality). Very little is known about the function of the protein encoded by C12orf57. Expression of C12orf57 is enriched in adult human lung tissue and human fetal brain (Akizu et al. 2013. PubMed ID: 23453666). It has been suggested that C12orf57 may play a role in eye and brain development based on the features observed in Temtamy syndrome patients (Zahrani et al. 2013. PubMed ID: 23453665).

Clinical Sensitivity - Sequencing with CNV PGxome

The clinical sensitivity of this test is difficult to estimate because of the phenotypic overlap with other disorders featuring intellectual disability, brain malformations, and eye malformations. Other disorders with similar clinical features include Peters-Plus syndrome, Muscular Dystrophy-Dystroglycanopathy (also known as Walker-Warburg syndrome and muscle-eye-brain disease), Aicardi-Goutieres syndrome, Donnai-Barrow syndrome, and Baraitser-Winter syndrome.

Testing Strategy

This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.

This test provides full coverage of all coding exons of the C12orf57 gene plus 10 bases flanking noncoding DNA in all available transcripts in addition to 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 include individuals with features consistent with Temtamy syndrome such as global developmental delay, intellectual disability, autistic behavior, seizures, corpus callosum abnormalities, and ocular anomalies. Targeted testing is indicated for family members of patients who have known pathogenic variants in C12orf57. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in C12orf57.

Gene

Official Gene Symbol OMIM ID
C12orf57 615140
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Temtamy Syndrome AR 218340

Citations

  • Akizu et al. 2013. PubMed ID: 23453666
  • Alrakaf et al. 2018. PubMed ID: 29383837
  • Anazi et al. 2016. PubMed ID: 27431290
  • Genome Aggregation Database.
  • Li et al. 2007. PubMed ID: 17632789
  • Monies et al. 2017. PubMed ID: 28600779
  • Online Gene Essentiality.
  • Platzer et al. 2014. PubMed ID: 24798461
  • Salih et al. 2013. PubMed ID: 23633300
  • Wang et al. 2020. PubMed ID: 31853307
  • Zahrani et al. 2013. PubMed ID: 23453665

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

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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ORDER OPTIONS

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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