Joubert Syndrome Type 2 (TMEM216), 1 Variant
Ordering Recommendation

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

Polymerase Chain Reaction/Fluorescence Monitoring
Tue, Fri
5-10 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes. 
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.

Hotline History
Component Test Code*Component Chart NameLOINC
2013910Joubert Syndrome Type 2, Specimen
2013911Joubert Syndrome Type 2, Allele 1
2013912Joubert Syndrome Type 2, Allele 2
2013913Joubert Syndrome Type 2, Interp
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