Connect Sign In
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.
New York DOH Approval Status
Specimen Required
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Refrigerated.
Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes. Frozen specimens in glass collection tubes.
Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month
Methodology
Polymerase Chain Reaction (PCR)/Fluorescence Monitoring
Performed
Tue, Fri
Reported
5-10 days
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.
Laboratory Developed Test (LDT)
Note
Hotline History
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 |
