colobomata

Baraitser-Winter Syndrome 2

Clinical Characteristics
Ocular Features: 

Hypertelorism, high arched eyebrows, ptosis, and  colobomas occur in the majority of individuals.

Systemic Features: 

Short stature, postnatal microcephaly, lissencephaly, intellectual disability, seizures, and sensorineural hearing loss are common.

Genetics

This syndrome can be considered to be an autosomal dominant disorder secondary to heterozygous mutations in the ACTG1 gene (17q25.3).  However, all patients have been sporadic.

Mutations in ACTG1 are also responsible for autosomal dominant progressive nonsyndromic hearing loss.  

A similar but unique condition known as Baraitser-Winter syndrome 1 (243310) is caused by heterozygous mutations in the ACTB gene. 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no known treatment but special education, hearing devices, and physical therapy may be helpful.

References
Article Title: 

Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases

Verloes A, Di Donato N, Masliah-Planchon J, Jongmans M, Abdul-Raman OA, Albrecht B, Allanson J, Brunner H, Bertola D, Chassaing N, David A, Devriendt K, Eftekhari P, Drouin-Garraud V, Faravelli F, Faivre L, Giuliano F, Guion Almeida L, Juncos J, Kempers M, Eker HK, Lacombe D, Lin A, Mancini G, Melis D, Lourenco CM, Siu VM, Morin G, Nezarati M, Nowaczyk MJ, Ramer JC, Osimani S, Philip N, Pierpont ME, Procaccio V, Roseli ZS, Rossi M, Rusu C, Sznajer Y, Templin L, Uliana V, Klaus M, Van Bon B, Van Ravenswaaij C, Wainer B, Fry AE, Rump A, Hoischen A, Drunat S, Riviere JB, Dobyns WB, Pilz DT. Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases. Eur J Hum Genet. 2014 Jul 23.

PubMed ID: 
25052316

De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome

Riviere JB, van Bon BW, Hoischen A, Kholmanskikh SS, O'Roak BJ, Gilissen C, Gijsen S, Sullivan CT, Christian SL, Abdul-Rahman OA, Atkin JF, Chassaing N, Drouin-Garraud V, Fry AE, Fryns JP, Gripp KW, Kempers M, Kleefstra T, Mancini GM, Nowaczyk MJ, van Ravenswaaij-Arts CM, Roscioli T, Marble M, Rosenfeld JA, Siu VM, de Vries BB, Shendure J, Verloes A, Veltman JA, Brunner HG, Ross ME, Pilz DT, Dobyns WB. De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome. Nat Genet. 2012 Feb 26;44(4):440-4.

PubMed ID: 
22366783

Baraitser-Winter Syndrome 1

Clinical Characteristics
Ocular Features: 

Ptosis (both unilateral and bilateral), hypertelorism, prominent epicanthal folds, and colobomata are common.  The iris stroma may be dysplastic and correctopia has been observed.  Visual acuity has not been measured.

Systemic Features: 

Postnatal growth retardation leads to short stature.  Microcephaly and morphological aberrations in the brain such as lissencephaly, agenesis of the corpus callosum and pachygyria are present.  Seizures and developmental delays are common.  Hearing loss is sensorineural in type.

The ears are low-set and the posterior hair line may be low as well.  The nasal bridge appears broad and the nose appears short. Male genitalia are often underdeveloped.  Bicuspid aortic valves, patent ductus arteriosus, and aortic stenosis have been reported.

Genetics

Heterozygous mutations in the ACTB gene (7p22.1) are responsible for this apparent autosomal dominant syndrome.  However, all patients have been sporadic.

This condition is clinically similar to Baraitser-Winter syndrome 2 (614583) which is a unique entity caused by a mutation in ACTG1. 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No specific treatment is available.

References
Article Title: 

New ocular finding in Baraitser-Winter syndrome

Rall N, Leon A, Gomez R, Daroca J, Lacassie Y. New ocular finding in Baraitser-Winter syndrome. Eur J Med Genet. 2017 Oct 9. pii: S1769-7212(17)30156-8. doi: 10.1016/j.ejmg.2017.10.006. [Epub ahead of print].

PubMed ID: 
29024830

Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases

Verloes A, Di Donato N, Masliah-Planchon J, Jongmans M, Abdul-Raman OA, Albrecht B, Allanson J, Brunner H, Bertola D, Chassaing N, David A, Devriendt K, Eftekhari P, Drouin-Garraud V, Faravelli F, Faivre L, Giuliano F, Guion Almeida L, Juncos J, Kempers M, Eker HK, Lacombe D, Lin A, Mancini G, Melis D, Lourenco CM, Siu VM, Morin G, Nezarati M, Nowaczyk MJ, Ramer JC, Osimani S, Philip N, Pierpont ME, Procaccio V, Roseli ZS, Rossi M, Rusu C, Sznajer Y, Templin L, Uliana V, Klaus M, Van Bon B, Van Ravenswaaij C, Wainer B, Fry AE, Rump A, Hoischen A, Drunat S, Riviere JB, Dobyns WB, Pilz DT. Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases. Eur J Hum Genet. 2014 Jul 23.

PubMed ID: 
25052316

De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome

Riviere JB, van Bon BW, Hoischen A, Kholmanskikh SS, O'Roak BJ, Gilissen C, Gijsen S, Sullivan CT, Christian SL, Abdul-Rahman OA, Atkin JF, Chassaing N, Drouin-Garraud V, Fry AE, Fryns JP, Gripp KW, Kempers M, Kleefstra T, Mancini GM, Nowaczyk MJ, van Ravenswaaij-Arts CM, Roscioli T, Marble M, Rosenfeld JA, Siu VM, de Vries BB, Shendure J, Verloes A, Veltman JA, Brunner HG, Ross ME, Pilz DT, Dobyns WB. De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome. Nat Genet. 2012 Feb 26;44(4):440-4.

PubMed ID: 
22366783
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