Joubert syndrome (JBTS) is an autosomal recessive set of disorders characterized by a specific midhindbrain malformation, hypotonia, cerebellar ataxia, and developmental delay. The most prominent characteristic of JBTS is the molar tooth sign in brain MRIs: deep interpeduncular fossa, thick, elongated superior cerebellar peduncles and cerebellar vermis hypoplasia. In the Ashkenazi Jewish population, a founder mutation p.R12L in the gene TMEM216 was identified for JBTS Type 2. The carrier frequency for this mutation in the Ashkenazi Jewish population is estimated to be 1/110. Since this is the only mutation reported for JBTS2 in this population, the carrier detection rate is estimated to be at least 95%. Carrier screening for JBTS2 may be considered for individuals of Eastern European (Ashkenazi) Jewish ancestry before/during pregnancy.
1. Edvardson, S. et al. Joubert syndrome 2 (JBTS2) in Ashkenazi Jews is associated with a TMEM216 mutation. Am J Hum Genet 86, 93-7 (2010).
2. Keeler, L.C. et al. Linkage analysis in families with Joubert syndrome plus oculo-renal involvement identifies the CORS2 locus on chromosome 11p12-q13.3. Am J Hum Genet 73, 656-62 (2003).
Two 5-10 ml tubes of anticoagulated blood. The preferred anticoagulant is EDTA (lavendar top tubes), ACD (yellow top) tubes are also accepted.
Shipping: Send at room temperature.
Turnaround Time: 10-14 days
CPT Codes: 83891, 83892x2, 83898, 83912, 83914
Consent and Requisition Forms: Carrier Screening Requisition and Consent [PDF]
Additional Information: Jewish Genetic Screening Brochure [PDF]
Related Tests: Ashkenazi Jewish Carrier Test Panel
Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.