Rubinstein-Taybi Syndrome 2

Clinical Characteristics
Ocular Features: 

Highly-arched and bushy eyebrows are often seen.  The lashes are long and bushy and lid fissures tend to slope downward.

The ocular phenotype has not been fully described no doubt due to the rarity of cases.  Individuals with type 1 (RSTS1) have been described with congenital glaucoma, nystagmus, corneal abnormalities of shape (such as keratoglobus, sclerocornea, megalocornea), pigmentary retinopathy, and VEP evidence of rod and cone dysfunction have been described.

Systemic Features: 

The phenotype of RSTS2 is more variable than the somewhat similar RSTS1.  Less than 10% of individuals with Rubinstein-Taybi syndrome have type 2 while over 50% have type 1.  The facial dysmorphism nay be less severe in RSTS2.

Mild to moderate intellectual disability with psychosocial problems such as autism is nearly universal.  Microcephaly, a broad nasal bridge, a beaked nose, high-arched palate and some degree of micrognathia are characteristic.  The lower lip often appears 'pouty' and protrudes beyond the upper lip while the hard palate is highly arched.  Pregnancy may be complicated by pre-eclampsia and growth restriction.  Swallowing and feeding issues are common.  Syndactyly is often present and there is considerable variability in the size of the toes and thumbs.  Some patients with RSTS2 do not have evidence of the classic broad thumbs and toes characteristic of RSTS1.

Genetics

Heterozygous mutations in EP300 (22q13.2) have been found in this condition.  Virtually all cases occur de novo.  Rubinstein-Taybi Syndrome 1 (180849) is a phenotypically similar disorder resulting from a different mutation (CREBBP).

Treatment
Treatment Options: 

There is no treatment for this condition.

References
Article Title: 

References

Lopez M, Garcia-Oguiza A, Armstrong J, Garcia-Cobaleda I, Garcia-Minaur S, Santos-Simarro F, Seidel V, Dominguez-Garrido E. Rubinstein-Taybi 2 associated to novel EP300 mutations: deepening the clinical and genetic spectrum. BMC Med Genet. 2018 Mar 5;19(1):36. doi: 10.1186/s12881-018-0548-2.

PubMedID: 29506490

Hamilton MJ, Newbury-Ecob R, Holder-Espinasse M, Yau S, Lillis S, Hurst JA, Clement E, Reardon W, Joss S, Hobson E, Blyth M, Al-Shehhi M, Lynch SA, Suri M; DDD Study. Rubinstein-Taybi syndrome type 2: report of nine new cases that extend the phenotypic and genotypic spectrum. Clin Dysmorphol. 2016 Jul 26. [Epub ahead of print].

PubMedID: 27465822

Bartsch O, Labonte J, Albrecht B, Wieczorek D, Lechno S, Zechner U, Haaf T. Two patients with EP300 mutations and facial dysmorphism different from the classic Rubinstein-Taybi syndrome. Am J Med Genet A. 2010 Jan;152A(1):181-4.

PubMedID: 20014264