Neurol India Home 
 

NEUROIMAGE
Year : 2008  |  Volume : 56  |  Issue : 2  |  Page : 223-

Molar tooth sign: Neuroimaging characteristic of Joubert syndrome

Tarun Nagpal, Sanjay Pande 
 Jabalpur Hospital and Research Centre and Netaji Subhash Chandra Bose Medical College, Jabalpur, India

Correspondence Address:
Tarun Nagpal
Jabalpur Hospital and Research Centre and Netaji Subhash Chandra Bose Medical College, Jabalpur
India




How to cite this article:
Nagpal T, Pande S. Molar tooth sign: Neuroimaging characteristic of Joubert syndrome.Neurol India 2008;56:223-223


How to cite this URL:
Nagpal T, Pande S. Molar tooth sign: Neuroimaging characteristic of Joubert syndrome. Neurol India [serial online] 2008 [cited 2020 Apr 6 ];56:223-223
Available from: http://www.neurologyindia.com/text.asp?2008/56/2/223/42019


Full Text

A two-year-old boy, born of non-consanguineous marriage was brought with delayed motor and language milestones. The parents had also noted abnormal eye movements and periodic breathing difficulty since early infancy. The child was third of three sibs and the other two sibs were normal. On examination, the child was hypotonic and mentally retarded and had severe truncal ataxia and oculomotor apraxia. Axial magnetic resonance imaging (MRI) Brain showed split, segmented vermis and elongated fourth ventricle giving the midbrain an appearance of 'molar tooth' [Figure 1]. The child was diagnosed to suffer from Joubert syndrome and the prognosis explained.

Joubert syndrome is a rare autosomal recessive disorder with a locus on Chromosome 9q characterized by ataxia, developmental delay and oculomotor and respiratory abnormalities in relation to cerebellar vermian and midbrain dysgenesis. [1] Joubert syndrome is often missed clinically and radiologically if not enough attention is paid to its subtle and variable clinical presentation and the imaging findings in the posterior fossa. A variety of abnormalities have been described in children with Joubert syndrome including delayed language, hypersensitivity to noise, autism, meningoencephaloceles, microcephaly, low-set ears, polydactyly, retinal dysplasia, kidney abnormalities (renal cysts), soft tissue tumor of the tongue, liver disease and duodenal atresia. Even within siblings the phenotype may vary, making it difficult to establish the exact clinical diagnostic boundaries of Joubert syndrome. The midbrain dysgenesis is responsible for the molar tooth sign on axial MRI which has also been documented in fetal brain MRI. [2]

References

1Saar K, Al-Gazali L, Sztriha L, Rueschendorf F, Nur-E-Kamal M, Reis A, et al . Homozygosity mapping in families with Joubert syndrome identifies a locus on chromosome 9q34.3 and evidence for genetic heterogeneity. Am J Hum Genet 1999;65:1666-71.
2Fluss J, Blaser S, Chitayat D, Akoury H, Glanc P, Skidmore M, 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.