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--- joubert_syndrome [2015/11/10 01:36] – created admin
+++ joubert_syndrome [2025/11/02 23:26] (current) – [Etiology] Scott Larson
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+====== Joubert Syndrome ======
+==== Main Features ====
+  * Cerebellar vermis hypoplasia or aplasia
+  * episodic tachypnea ("panting like a dog") and apnea in infancy
+  * jerky eye movements, hypotonia, developmental delay
+==== Eye Findings ====
+  * **Ocular Motor Abnormalities**
+    * Oculomotor Apraxia
+      * inability to voluntarily initiate saccades and compensate by using head thrusts.
+    * Absent smooth pursuit
+    * Hypometric saccades with prolonged latency; they change direction of fixation by turning their heads
+    * Nystagmus – pendular, rotary, horizontal, see-saw, torsional
+    * Supranuclear Ocular motor palsies
+    * Strabismus (up to 80%)
+      * Horizontal (esotropia or exotropia) or vertical
+  * **Congenital Retinal Dystrophy** (30%)
+      * Progressive chorioretinal pigmentary changes including reports of "mottling" in periphery
+      * Attenuation of retinal arterioles
+      * Nonrecordable / attenuated ERG, but Preserved flash and pattern VEPs (Differentiates from LCA)
+      * 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
+  * Chorioretinal coloboma 17%-30%
+  * Optic Nerve coloboma.
+=== 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
+  * Joubert’s generally has better Visual acuity
+==== Etiology ====
+  * 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
+  * More commonly reported in cultures of consanguinity, although distributed worldwide
+==== Other Findings ====
+  * Neuro: Mental retardation, ataxia
+  * Respiratory: Episodic tachypnea and apnea that improves with age
+  * Renal: Renal cysts, inflammation, sclerosis, can be deadly
+  * GI: protruding tongue, tongue tumors, pyloric stenosis, duodenal atresia, hepatic inflammation
+  * Bone: Polydactyly
+==== 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
+  * Sztriha, et al. Ped Neurol 1999; 20:274-281
+  * Saraiva, Am J of Med Genetics 1992; 43:726-731
+  * OMIM [[http://omim.org/entry/213300|213300]], [[http://omim.org/entry/608091|608091]]
+{{tag>Syndrome}}

syndrome