Abstract
Joubert syndrome (JS) and related disorders (JSRD) are a group of multiple congenital anomaly syndromes in which the diagnostic hallmark is the molar tooth sign (MTS), a complex midbrain malformation visible on brain imaging. Detection of the MTS should be followed by a diagnostic protocol to assess multi-organ involvement. The incidence of JSRD ranges between 1/80,000 and 1/100,000 live births, although these values may represent an underestimate. The neurological components of JSRD include hypotonia, ataxia, intellectual disability, abnormal eye movements, and neonatal breathing problems. These may be associated with multi-organ involvement, mainly retinal dystrophy, nephronophthisis, hepatic fibrosis, and polydactyly. With the exception of rare X-linked recessive cases, JSRD follow autosomal recessive inheritance and are genetically heterogeneous. Ten causative genes have been identified to date, all encoding for proteins of the primary cilium, making JSRD part of a group of diseases called “ciliopathies”. Analysis of causative genes is available in few laboratories worldwide on a research basis. The differential diagnosis must consider, in particular, the other ciliopathies, distinct cerebellar and brainstem congenital defects, and disorders with cerebro–oculo–renal manifestations. Recurrence risk is 25% in most families, although X-linked inheritance should also be considered. Optimal management requires a multidisciplinary approach, with particular attention paid to respiratory problems in neonates. After the first months of life, the prognosis varies among JSRD subgroups, depending on the extent and severity of organ involvement.
Similar content being viewed by others
References
Joubert M, Eisenring JJ, Robb JP, et al. Familial agenesis of the cerebellar vermis. A syndrome of episodic hyperpnea, abnormal eye movements, ataxia, and retardation. Neurology. 1969;19:813–25.
Maria BL, Hoang KB, Tusa RJ, et al. Joubert syndrome revisited: key ocular motor signs with magnetic resonance imaging correlation. J Child Neurol. 1997;12:423–30.
Yachnis AT, Rorke LB. Neuropathology of Joubert syndrome. J Child Neurol. 1999;14:655–9.
Spampinato MV, Kraas J, Maria BL, et al. Absence of decussation of the superior cerebellar peduncles in patients with Joubert syndrome. Am J Med Genet. 2008;146A:1389–94.
Gleeson JG, Keeler LC, Parisi MA, et al. Molar tooth sign of the midbrain-hindbrain junction: occurrence in multiple distinct syndromes. Am J Med Genet. 2004;125A:125–34.
Valente EM, Salpietro DC, Brancati F, et al. Description, nomenclature, and mapping of a novel cerebello-renal syndrome with the molar tooth malformation. Am J Hum Genet. 2003;73:663–70.
Steinlin M, Schmid M, Landau K, et al. Follow-up in children with Joubert syndrome. Neuropediatrics. 1997;28:204–11.
Dixon-Salazar T, Silhavy JL, Marsh SE, et al. Mutations in the AHI1 gene, encoding jouberin, cause Joubert syndrome with cortical polymicrogyria. Am J Hum Genet. 2004;75:979–87.
Lancaster MA, Gleeson JG. The primary cilium as a cellular signaling center: lessons from disease. Curr Opin Genet Dev. 2009;19:220–9.
Badano JL, Mitsuma N, Beales PL, et al. An emerging class of human genetic disorders. Ann Rev Genomics Hum Genet. 2006;7:125–48.
Bielas SL, Silhavy J, Brancati L, et al. Mutations in INPP5E, encoding inositol polyphosphate-5-phosphatase E, link phosphatidyl inositol signaling to the ciliopathies. Nature Genet. 2009;41:1032–6.
Bromley B, Nadel AS, Pauker S, et al. Closure of the cerebellar vermis: evaluation with second trimester US. Radiology. 1994;193:761–3.
Nyberg DA, Cyr DR, Mack LA, et al. The Dandy-Walker malformation prenatal sonographic diagnosis and its clinical significance. J Ultrasound Med. 1988;7:65–71.
Barkovich AJ, Kjos BO, Norman D, et al. Revised classification of posterior fossa cysts and cystlike malformations based on the results of multiplanar MR imaging. Am J Roentgenol. 1989;103:1289–300.
Carroll SG, Porter H, Abdel-Fattah S, et al. Correlation of prenatal ultrasound diagnosis and pathologic findings in fetal brain abnormalities. Ultrasound Obstet Gynecol. 2000;16:149–53.
Laing FC, Frates MC, Brown DL, et al. Sonography of the fetal posterior fossa: false appearance of mega-cisterna magna and Dandy-Walker variant. Radiology. 1994;192:247–51.
Maria BL, Boltshauser E, Palmer SC, et al. Clinical features and revised diagnostic criteria in Joubert syndrome. J Child Neurol. 1999;14:583–90.
Parisi MA. Clinical and molecular features of Joubert syndrome and related disorders. Am J Med Genet C Semin Med Genet. 2009;151C:326–40.
Maria BL, Quisling RG, Rosainz LC, et al. Molar tooth sign in Joubert syndrome: clinical, radiologic, and pathologic significance. J Child Neurol. 1999;14:368–76.
Pugash D, Oh T, Godwin K, et al. Sonographic ‘molar tooth’ sign in the diagnosis of Joubert syndrome. Ultrasound Obstet Gynecol. 2011;38:598–602.
Saleem SN, Zaki MS, Soliman NA, et al. Prenatal magnetic resonance imaging diagnosis of molar tooth sign at 17–18 weeks of gestation in two fetuses at risk for Joubert syndrome and related cerebellar disorders. Neuropediatrics. 2011;42:35–8.
Doherty D, Glass IA, Siebert JR, et al. Prenatal diagnosis in pregnancies at risk for Joubert syndrome by ultrasound and MRI. Prenat Diagn. 2005;25:442–7.
Fluss J, Blaser S, Chitayat D, et al. Molar tooth sign in fetal brain magnetic resonance imaging leading to the prenatal diagnosis of Joubert syndrome and related disorders. J Child Neurol. 2006;21:320–4.
Iskender CT, Tarım E, Alkan O. Joubert syndrome and related disorders, prenatal diagnosis with ultrasound and magnetic resonance imaging. J Turk Ger Gynecol Assoc. 2012;13:135–8.
Bosemani Thangamadhan, Orman Gunes, Boltshauser Eugen, et al. Congenital abnormalities of the posterior fossa. Radiographics. 2015;35:200–20.
Shen WC, Shian WJ, Chen CC, et al. MRI of Jouberts syndrome. Eur J Radiol. 1994;18:30–3.
Babcook CJ, Chong BW, Salamat MS, et al. Sonographic anatomy of the developing cerebellum: normal embryology can resemble pathology. AJR Am J Roentgenol. 1996;166:427–33.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that there are no conflicts of interest.
Ethical statements
This article does not contain any studies with human or animal subjects performed by any of the authors.
About this article
Cite this article
Buke, B., Canverenler, E., İpek, G. et al. Diagnosis of Joubert syndrome via ultrasonography. J Med Ultrasonics 44, 197–202 (2017). https://doi.org/10.1007/s10396-016-0751-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10396-016-0751-8