Joubert syndrome

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Joubert disease
Classification and external resources
ICD-10 Q04.3
ICD-9 742.2
OMIM 213300
DiseasesDB 30688

Joubert syndrome is a rare genetic disorder that affects the cerebellum, an area of the brain that controls balance and coordination.

Diagnosis[edit]

The disorder is characterized by absence or underdevelopment of the cerebellar vermis and a malformed brain stem (molar tooth sign).[1] The most common features include ataxia (lack of muscle control), hyperpnea (abnormal breathing patterns), sleep apnea, abnormal eye and tongue movements, and hypotonia. Other malformations such as extra fingers and toes, cleft lip or palate, tongue abnormalities, and seizures may also occur. There may be mild or moderate retardation. Joubert syndrome is one of the many genetic syndromes associated with syndromic retinitis pigmentosa.[2] The syndrome was first identified by pioneering pediatric neurologist Marie Joubert in Montreal, Canada, while working at the Montreal Neurological Institute and McGill University.[3]

Treatment[edit]

Treatment for Joubert syndrome is symptomatic and supportive. Infant stimulation and physical, occupational,speech and hearing therapy may benefit some patients. Infants with abnormal breathing patterns should be monitored.

Prognosis[edit]

The prognosis for individuals with Joubert syndrome varies. Some patients have a mild form with minimal motor disability and good mental development, while others may have severe motor disability and moderate mental retardation.

Genetics[edit]

A number of mutations have been identified in individuals with Joubert syndrome (JBTS) which allowed for classification of the disorder into subtypes.

Type OMIM Gene Locus Inheritance Remarks
JBTS1 213300 INPP5E 9q34.3 Autosomal recessive Also known as Cerebellooculorenal syndrome 1 (CORS1)
JBTS2 608091 TMEM216 11q12.2 Autosomal recessive Also known as Cerebellooculorenal syndrome 2 (CORS2)
JBTS3 608629 AHI1 6q23.3 Autosomal recessive
JBTS4 609583 NPHP1 2q13
JBTS5 610188 CEP290
NPHP6
12q21.32 Autosomal recessive
JBTS6 610688 TMEM67 8q22.1 Autosomal recessive
JBTS7 611560 RPGRIP1L 16q12.2
JBTS8 612291 ARL13B 3q11.1
JBTS9 612285 CC2D2A 4p15.32 Autosomal recessive
JBTS10 300804 OFD1 Xp22.2 X-linked recessive
JBTS11 TTC21B 2q24.3
JBTS12 KIF7 15q26.1
JBTS13 614173 TCTN1 12q24.11
JBTS14 614424 TMEM237 2q33.1 Autosomal recessive
JBTS15 614464 CEP41 7q32.2 Autosomal recessive
JBTS16 614465 TMEM138 11q12.2 Autosomal recessive
JBTS17 614615 C5ORF42 5p13.2
JBTS18 614815 TCTN3 10q24.1
JBTS19 ZNF423 16q12.1 Autosomal dominant
JBTS20 614970 TMEM231 16q23.1 Autosomal recessive
611654 CSPP1,[4][5][6] 8q13.2 Autosomal recessive

Ciliopathy[edit]

Research has revealed that a number of genetic disorders, not previously thought to be related, may indeed be related as to their root cause. Joubert syndrome is one such disease. It is a member of an emerging class of diseases called ciliopathies.

The underlying cause of the ciliopathies may be a dysfunctional molecular mechanism in the primary cilia structures of the cell, organelles which are present in many cellular types throughout the human body. The cilia defects adversely affect "numerous critical developmental signaling pathways" essential to cellular development and thus offer a plausible hypothesis for the often multi-symptom nature of a large set of syndromes and diseases.

Currently recognized ciliopathies include Joubert syndrome, primary ciliary dyskinesia (also known as Kartagener Syndrome), Bardet-Biedl syndrome, polycystic kidney disease and polycystic liver disease, nephronophthisis, Alstrom syndrome, Meckel-Gruber syndrome and some forms of retinal degeneration.[7]

References[edit]

  1. ^ Brancati F, Dallapiccola B, Valente EM (2010). "Joubert Syndrome and related disorders". Orphanet J Rare Dis 5: 20. doi:10.1186/1750-1172-5-20. PMC 2913941. PMID 20615230. 
  2. ^ Saraiva, JM; Baraitser, M (1992). "Joubert syndrome: a review". American Journal of Medical Genetics 43 (4): 726–731. doi:10.1002/ajmg.1320430415. PMID 1341417. 
  3. ^ Joubert M, Eisenring JJ, Robb JP, Andermann F (September 1969). "Familial agenesis of the cerebellar vermis. A syndrome of episodic hyperpnea, abnormal eye movements, ataxia, and retardation". Neurology 19 (9): 813–25. PMID 5816874. 
  4. ^ Shaheen, R.; Shamseldin, H. E.; Loucks, C. M.; Seidahmed, M. Z.; Ansari, S.; Ibrahim Khalil, M.; Al-Yacoub, N.; Davis, E. E.; Mola, N. A.; Szymanska, K.; Herridge, W.; Chudley, A. E.; Chodirker, B. N.; Schwartzentruber, J.; Majewski, J.; Katsanis, N.; Poizat, C.; Johnson, C. A.; Parboosingh, J.; Boycott, K. M.; Innes, A.  M.; Alkuraya, F. S. (2013). "Mutations in CSPP1, Encoding a Core Centrosomal Protein, Cause a Range of Ciliopathy Phenotypes in Humans". The American Journal of Human Genetics 94 (1): 73–9. doi:10.1016/j.ajhg.2013.11.010. PMID 24360803.  edit
  5. ^ Akizu, N.; Silhavy, J. L.; Rosti, R. O.; Scott, E.; Fenstermaker, A. G.; Schroth, J.; Zaki, M. S.; Sanchez, H.; Gupta, N.; Kabra, M.; Kara, M.; Ben-Omran, T.; Rosti, B.; Guemez-Gamboa, A.; Spencer, E.; Pan, R.; Cai, N.; Abdellateef, M.; Gabriel, S.; Halbritter, J.; Hildebrandt, F.; Van Bokhoven, H.; Gunel, M.; Gleeson, J. G. (2013). "Mutations in CSPP1 Lead to Classical Joubert Syndrome". The American Journal of Human Genetics 94 (1): 80–6. doi:10.1016/j.ajhg.2013.11.015. PMID 24360807.  edit
  6. ^ Tuz, K.; Bachmann-Gagescu, R.; o’Day, D. R.; Hua, K.; Isabella, C. R.; Phelps, I. G.; Stolarski, A. E.; o’Roak, B. J.; Dempsey, J. C.; Lourenco, C.; Alswaid, A.; Bönnemann, C. G.; Medne, L.; Nampoothiri, S.; Stark, Z.; Leventer, R. J.; Topçu, M.; Cansu, A.; Jagadeesh, S.; Done, S.; Ishak, G. E.; Glass, I. A.; Shendure, J.; Neuhauss, S. C. F.; Haldeman-Englert, C. R.; Doherty, D.; Ferland, R. J. (2013). "Mutations in CSPP1 Cause Primary Cilia Abnormalities and Joubert Syndrome with or without Jeune Asphyxiating Thoracic Dystrophy". The American Journal of Human Genetics 94 (1): 62–72. doi:10.1016/j.ajhg.2013.11.019. PMID 24360808.  edit
  7. ^ Badano, Jose L.; Norimasa Mitsuma; Phil L. Beales; Nicholas Katsanis (September 2006). "The Ciliopathies : An Emerging Class of Human Genetic Disorders". Annual Review of Genomics and Human Genetics 7: 125–148. doi:10.1146/annurev.genom.7.080505.115610. PMID 16722803. Retrieved 2008-06-15. 

External links[edit]