From Wikipedia, the free encyclopedia
Medical condition
Temple–Baraitser syndrome (TBS) is a very rare
autosomal dominant genetic disorder, characterised by
intellectual disability ,
epilepsy , small or absent nail of the thumbs and great toes, and distinct craniofacial features.
[1]
Genetics
TBS is caused by pathogenic variants (
mutations ) in the
KCNH1
gene at chromosomal
locus 1q32.2, (GRCh38): 1:210,678,313-211,134,147.
[2] It has an
autosomal dominant transmission, however affected individuals are not known to reproduce, so all reported cases have been caused by
de novo mutations or transmission from a
mosaic parent.
[3]
Diagnosis
Temple–Baraitser syndrome is diagnosed by clinical examination of a person with a severe
developmental disability ,
intellectual impairment and
epilepsy . The face is often long and
myopathic .
Overgrown gums become apparent in late childhood. The
finger and toenails are characteristically small, with complete or almost complete absence of the nails of the
thumb (pollex) and
great toe (hallux).
[4]
[5] The diagnosis can be confirmed by demonstrating a
gain-of-function
mutation in the
KCNH1 gene.
[6] Temple–Baraitser has clinical and genetic overlap with type 1
Zimmermann–Laband syndrome .
[7]
Management
Affected individuals should see a
pediatrician or
adult physician at least annually to monitor growth, development, seizures and general health and well-being. Developmental potential is maximized through the use of
physiotherapy ,
occupational therapy and
speech pathology .
Anticonvulsants are used to control epilepsy.
[8]
Prevalence
With fewer than 100 cases having been reported worldwide, the exact prevalence is unknown but is believed to be rare. It is likely to be underdiagnosed, with one large study identifying 2.7% of people with intellectual disability to have a mutation in
KCNH1 .
[9]
Etymology
The syndrome's named was coined by
Michael Gabbett who named it after English
clinical geneticists Karen Temple and Michael Baraitser.
[10]
[11] Temple and Baraitser described the first case in 1991.
[12]
[13]
References
^ Vilain, C.
"Temple-Baraitser syndrome" . Orphanet.
^ Simons, Cas; Rash, Lachlan D.; Crawford, Joanna; Ma, Linlin; Cristofori-Armstrong, Ben; Miller, David; Ru, Kelin; Baillie, Gregory J.; Alanay, Yasemin; Jacquinet, A; Debray, FG; Verloes, A; Shen, J; Yesil, G; Guler, S; Yuksel, A; Cleary, JG; Grimmond, SM; McGaughran, J; King, GF; Gabbett, Michael T.; Taft, RJ. (January 2015). "Mutations in the voltage-gated potassium channel gene KCNH1 cause Temple–Baraitser syndrome and epilepsy". Nature Genetics . 47 (1): 73–77.
doi :
10.1038/ng.3153 .
ISSN
1061-4036 .
PMID
25420144 .
S2CID
52799681 .
^ Genetic Services Laboratory.
"Temple–Baraitser syndrome testing: Mutation analysis of KCNH1" (PDF) . University of Chicago.
^ Jacquinet, Adeline; Gérard, Marion; Gabbett, Michael T.; Rausin, Léon; Misson, Jean-Paul; Menten, Bjorn; Mortier, Geert; van Maldergem, Lionel; Verloes, Alain; Debray, François-Guillaume (2010).
"Temple–Baraitser Syndrome: A Rare and Possibly Unrecognized Condition" . Am J Med Genet A . 152A (9): 2322–2326.
doi :
10.1002/ajmg.a.33574 .
PMID
20683999 .
S2CID
205313155 .
^ McLaren, H.
"Temple-Baraitser syndrome" . Ontology Search . OLS. Retrieved 25 June 2022 .
^ Gabbett, Michael T.
"KCNH1 - Molecular Characteristics" . Human Disease Genes Website Series . Human Disease Genes. Retrieved 25 June 2022 .
^ Bramswig, Nuria C; Ockeloen, CW; Czeschik, JC; vanEssen, AJ; Pfundt, R; Smeitink, J; Poll-The, BT; Engels, H; Strom, TM; Wieczorek, D; Kleefstra, T; Lüdecke, HJ (2015).
" 'Splitting versus lumping': Temple-Baraitser and Zimmermann-Laband Syndromes" . Hum Genet . 134 (10): 1089–97.
doi :
10.1007/s00439-015-1590-1 .
PMID
26264464 .
S2CID
14238362 .
^ Gabbett, Michael T.
"KCNH1 Management" . Human Disease Genes.
^ Bramswig, NC; Ockeloen, CW; Czeschik, JC; van Essen, AJ; Pfundt, R; Smeitink, J; Poll-The, BT; Engels, H; Strom, TM; Wieczorek, D; Kleefstra, T; Lüdecke, HJ (2015).
"Splitting versus lumping': Temple–Baraitser and Zimmermann–Laband Syndromes" . Hum Genet . 134 (10): 1089–1097.
doi :
10.1007/s00439-015-1590-1 .
PMID
26264464 .
S2CID
14238362 .
^ Ward, Gemma (25 November 2014).
"Genetic test unlocks cause of Brisbane boy's rare disease" . The University of Queensland.
^ Pash, Chris.
"This Brisbane Boy Is Just One Of Seven People In The World With A Rare Condition" . Pedestrian Group.
^ Gabbett, Michael T.; Clark, Ronald C; McGaughran, Julie M (2008).
"A Second Case of Severe Mental Retardation and Absent Nails of Hallux and Pollex (Temple–Baraitser Syndrome)" . American Journal of Medical Genetics Part A . 146A (4): 450–452.
doi :
10.1002/ajmg.a.32129 .
PMID
18203178 .
S2CID
2532859 .
^ Temple, Karen I; Baraitser, Michael (1991).
"Severe mental retardation and absent nails of hallux and pollex" . Am J Med Genet . 41 (2): 173–175.
doi :
10.1002/ajmg.1320410207 .
PMID
1785628 .
External links
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