Joubert Syndrome Type II, DNA Analysis

CPT: 81479
Updated on 5/28/2019
Print Share


  • Jewish Heritage Test
  • TMEM216

Special Instructions

If cultured cells are needed, an additional 7-12 days may be required. Additional culture fee may be included.

Expected Turnaround Time

7 - 15 days

7 - 15 days

Specimen Requirements


Whole blood, amniotic fluid, chorionic villus sample (CVS) (Submission of maternal blood is required for fetal testing.), or LabCorp buccal swab kit (Buccal swab collection kit contains instructions for use of a buccal swab.)


7 mL whole blood, 10 mL amniotic fluid, 20 mg CVS, or LabCorp buccal swab kit

Minimum Volume

3 mL whole blood, 5 mL amniotic fluid, 10 mg CVS, or two buccal swabs


Lavender-top (EDTA) tube, yellow-top (ACD) tube, sterile plastic conical tube or two confluent T-25 flasks for fetal testing, or LabCorp buccal swab kit

Storage Instructions

Maintain specimen at room temperature or refrigerate at 4°C

Causes for Rejection

Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; one buccal swab; wet buccal swab

Test Details


Detect the presence of the R12L mutation (also called R73L) in the TMEM216 gene.


Polymerase chain reaction (PCR) and primer extension

Additional Information

Joubert syndrome type II (JBTS2, OMIM 608091) is an inherited, autosomal recessive early-onset disorder characterized by the absence or underdeveloped cerebellar vermis-an area of the brain that controls balance and coördination. This "molar tooth sign" can be seen on midbrain MRI. Common clinical findings in infants are abnormal rapid breathing, hypotonia, oculomotor apraxia/nystagmus, mental retardation, and an inability to coordinate voluntary muscle movements. Other findings include polydactyly, low-set ears, small genitalia, high-arched palate, and hepatic fibrosis. The disease has an elevated prevalence in the Ashkenazi Jewish population, with a carrier rate of 1 in 92. When both parents are carriers of JBTS2, there is a 25% chance with each pregnancy of having a child with the disease. Prenatal diagnosis is available.

Molecular genetic testing for JBTS2 encompasses one mutation in the TMEM216 gene (11q13). Testing for the R12L (also called R73L) mutation identifies approximately greater than 99% of JBTS2 carriers in the Ashkenazi Jewish population. The carrier frequency in the non-Ashkenazi Jewish population has not been determined. A negative result decreases the likelihood that this person is a carrier but cannot completely eliminate the possibility. The presence of a rare mutation cannot be ruled out. DNA test results must be combined with the clinical information for the most accurate interpretation.


Edvardson S, Shaag A, Zenvirt S, et al. Joubert syndrome 2 (JBTS2) in Ashkenazi Jews is associated with a TMEM216 mutation. Am J Hum Genet. 2010 Jan; 86(1):93-97.


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
511490 Joubert Syndrome Type II 511491 Joubert Syndrome Type II 41103-3
511490 Joubert Syndrome Type II 511952 PDF 51969-4

For Providers

Please login to order a test.


© 2019  Laboratory Corporation of America® Holdings and Lexi-Comp Inc. All Rights Reserved.

CPT Statement/Profile Statement

The LOINC® codes are copyright © 1994-2018, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at Additional information regarding LOINC® codes can be found at, including the LOINC Manual, which can be downloaded at