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
- Absent smooth pursuit
- Hypometric saccades with prolonged latency; they change direction of fixation by turning their heads
- Nystagmus – pendular, rotary, horizontal, see-saw, torsional
- Congenital Retinal Dystrophy (in majority of patients; some definitely have normal appearing fundi)
- Progressive chorioretinal pigmentary changes including reports of “mottling” in periphery
- Chorioretinal Coloboma
- 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
- Strabismus
- Supranuclear Ocular motor palsies
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
- Autosomal Recessive
- 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