JS is rare autosomal recessive inherited disorder suspected by hypotonia, ataxia, developmental delay, intellectual disability with distinctive mid-hindbrain malformation (molar tooth sign), ocular abnormalities (e.g., pigmentary retinopathy, oculomotor apraxia, and nystagmus), renal cyst and hepatic fibrosis, hyperpnea alternating with periods of apnea.
Valente, brancati, and dallapiccola proposed a clinical classification of JS in which molar tooth sign was consider as obligatory criteria and hypotonia, developmental delay, ataxia, abnormal eye movements were considered as primary criteria.
A brain MRI showed severe vermis hypoplasia, molar tooth sign, agenesis of corpus callosum, retrocerebellar enlargement (variant Dandy Walker syndrome?) and colpocephaly.
The deleted region involved a new gene that could be responsible for the clinical manifestations including cleft palate and Molar tooth sign, pyruvate dehydrogenase phosphatase regulatory subunit (PDPR).
Joubert Syndrome can be identified on axial magnetic resonance imaging as the molar tooth sign (MTS); other criteria include intellectual disability, hypotonia, and often, abnormal respiratory pattern and/or abnormal eye movements.
MRI brain showed 'Molor tooth sign' which is pathogonomic of Jouberts syndrome.
There are classic imaging findings in Joubert syndrome, including the molar tooth sign
and a bat-wing configuration of the fourth ventricle seen on axial MRI or CT.
Brain MRI examination revealed that all cases had molar tooth sign
, bat-wing appearance and vermian cleft.
The molar tooth sign
was initially identified in Joubert syndrome, named after Marie Joubert who first described it in 1968 as a rare autosomal recessive disorder characterised by the neuroradiological hallmark of the molar tooth sign
caused by cerebellar vermian hypoplasia.
Joubert syndrome (JS) is a rare genetic disorder that affects the cerebellum, controlling balance, and coordination, and it usually presents a molar tooth sign
on magnetic resonance imaging.
It revealed the midbrain malformations included fourth ventricle dilatation and superior cerebellar peduncle elongation, which forms the classically described "Molar tooth sign
Molar tooth sign
in fetal brain magnetic resonance imaging leading to the prenatal diagnosis of Joubert syndrome and related disorders.