Ordering Recommendation

Carrier screening or diagnostic testing for Joubert syndrome type 2 for individuals of Ashkenazi Jewish descent.

Mnemonic
TMEM216
Methodology

Polymerase Chain Reaction/Fluorescence Monitoring

Performed

Tue, Fri

Reported

5-10 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes.

Remarks
Stability

Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month

Reference Interval

By report

Interpretive Data

Background Information for Joubert Syndrome Type 2 (TMEM216), 1 Variant:
Characteristics: Joubert syndrome, type 2 is characterized by a "molar tooth sign" cerebellar and brain stem malformation, hypotonia and developmental delay. Clinical manifestations and severity of the syndrome vary.
Incidence: 1 in 34,000 in Ashkenazi Jewish individuals.
Inheritance: Autosomal recessive.
Cause: TMEM216 pathogenic variants.
Variants Tested: p.R73L (c.218G>T).
Clinical Sensitivity: 99 percent in Ashkenazi Jewish individuals; unknown in other ethnicities.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Variants other than p.R73L (c.218G>T) will not be detected. Diagnostic errors can occur due to rare sequence variations.

Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Note
Hotline History
N/A
CPT Codes

81479

Components
Component Test Code* Component Chart Name LOINC
2013910 Joubert Syndrome Type 2, Specimen
2013911 Joubert Syndrome Type 2, Allele 1
2013912 Joubert Syndrome Type 2, Allele 2
2013913 Joubert Syndrome Type 2, Interp
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
Joubert Syndrome Type 2 (TMEM216), 1 Variant