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joubert_syndrome [2025/04/18 20:40] – external edit 127.0.0.1joubert_syndrome [2025/11/02 23:26] (current) – [Etiology] Scott Larson
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   * episodic tachypnea ("panting like a dog") and apnea in infancy   * episodic tachypnea ("panting like a dog") and apnea in infancy
   * jerky eye movements, hypotonia, developmental delay   * jerky eye movements, hypotonia, developmental delay
 +
 ==== Eye Findings ==== ==== Eye Findings ====
   * **Ocular Motor Abnormalities**   * **Ocular Motor Abnormalities**
 +    * Oculomotor Apraxia 
 +      * inability to voluntarily initiate saccades and compensate by using head thrusts. 
     * Absent smooth pursuit     * Absent smooth pursuit
     * Hypometric saccades with prolonged latency; they change direction of fixation by turning their heads     * Hypometric saccades with prolonged latency; they change direction of fixation by turning their heads
     * Nystagmus – pendular, rotary, horizontal, see-saw, torsional     * Nystagmus – pendular, rotary, horizontal, see-saw, torsional
-  * **Congenital Retinal Dystrophy** (in majority of patients; some definitely have normal appearing fundi) +    * Supranuclear Ocular motor palsies 
-    * Progressive chorioretinal pigmentary changes including reports of "mottling" in periphery +    * Strabismus (up to 80%)  
-    * Chorioretinal Coloboma +      * Horizontal (esotropia or exotropia) or vertical  
-    * Attenuation of retinal arterioles +  * **Congenital Retinal Dystrophy** (30%) 
-    * Nonrecordable / attenuated ERG, but Preserved flash and pattern VEPs (Differentiates from LCA) +      * Progressive chorioretinal pigmentary changes including reports of "mottling" in periphery 
-    * Rod photoreceptors are more severely affected than cones +      * Attenuation of retinal arterioles 
-    * May have good Best Corrected Visual Acuity – reports of 20/40 (also better than LCA) +      * Nonrecordable / attenuated ERG, but Preserved flash and pattern VEPs (Differentiates from LCA) 
-    * Those with Retinal dystrophy also have Renal cysts and other kidney disease+      * Rod photoreceptors are more severely affected than cones 
 +      * May have good Best Corrected Visual Acuity – reports of 20/40 (also better than LCA) 
 +      * Those with Retinal dystrophy also have Renal cysts and other kidney disease
   * Ptosis – Bilateral or Unilateral   * Ptosis – Bilateral or Unilateral
-  * Strabismus +  * Chorioretinal coloboma 17%-30% 
-  * Supranuclear Ocular motor palsies+  * Optic Nerve coloboma.  
 === Differentiating Joubert’s from Leber’s Congenital Amaurosis === === Differentiating Joubert’s from Leber’s Congenital Amaurosis ===
   * Both have nonrecordable or severely attenuated ERG, but Joubert’s has recordable (less than normal) flash and pattern VEPs   * Both have nonrecordable or severely attenuated ERG, but Joubert’s has recordable (less than normal) flash and pattern VEPs
   * Joubert’s generally has better Visual acuity   * Joubert’s generally has better Visual acuity
 +
 ==== Etiology ==== ==== Etiology ====
-  * Autosomal Recessive+  * Defects in function of primary cilia, one of the ciliopathies  
 +  * Mostly Autosomal Recessive 
 +    * Half the cases have a mutation in only one of 4 genes: AHI1 15%, C5orf42 13%, KIAA0586 11% and CSPP1 10% 
 +    * at least 28 genes implicated most related to cilia formation/function 
 +    * 
   * First described in 1969, by 1991, 94 patients reported   * First described in 1969, by 1991, 94 patients reported
   * More commonly reported in cultures of consanguinity, although distributed worldwide   * More commonly reported in cultures of consanguinity, although distributed worldwide
 +
 ==== Other Findings ==== ==== Other Findings ====
   * Neuro: Mental retardation, ataxia   * Neuro: Mental retardation, ataxia
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   * GI: protruding tongue, tongue tumors, pyloric stenosis, duodenal atresia, hepatic inflammation   * GI: protruding tongue, tongue tumors, pyloric stenosis, duodenal atresia, hepatic inflammation
   * Bone: Polydactyly   * Bone: Polydactyly
 +
 ==== References ==== ==== References ====
 +  * [[https://pmc.ncbi.nlm.nih.gov/articles/PMC6315342/| Wang SF. et al. Review of Ocular Manifestations of Joubert Syndrome. Genes. 2018;9(12):605]]
   * Lambert, et al. Arch Ophth 1989;107:709-713   * Lambert, et al. Arch Ophth 1989;107:709-713
   * Sztriha, et al. Ped Neurol 1999; 20:274-281   * Sztriha, et al. Ped Neurol 1999; 20:274-281