Nicolaides-Baraitser syndrome

What causes Nicolaides-Baraitser syndrome?

Nicolaides-Baraitser syndrome (NCBRS) is caused by mutations in the SMARCA2 gene, which is located on the small arm of chromosome 9. All mutations that have been identified in affected people have been either missense mutations or in- frame deletions.

There may be some correlations between specific types of mutations and some of the features that result (called genotype-phenotype correlations), but more studies are needed to draw definitive conclusions.

Last updated on 05-01-20

How is Nicolaides-Baraitser syndrome inherited?

Nicolaides-Baraitser syndrome (NCBRS) is inherited in an autosomal dominant manner. This means that having a change (mutation) in only one of the two copies of the responsible gene in each cell is enough to cause features of the condition.

All known cases of NCBRS have been sporadic. This means it is thought that the mutation occurred for the first time in each affected person (called a de novo mutation). There have not been reports of NCBRS being inherited from a parent, or recurring in any family (with the exception of one pair of identical twins).

Last updated on 05-01-20

What is the long-term outlook for people with Nicolaides-Baraitser syndrome?

There is limited information about the life expectancy of people with Nicolaides-Baraitser syndrome (NCBRS) due to the rarity of the condition and the small number of reported cases in the literature. NCBRS was not recognized as a distinct condition until the 1990s, so there is limited information about older adults with NCBRS.

As of 2009, the first person reported with NCBRS was still living at age 32. Another person first reported in 1996 died at the age of 25 due to rupture of esophagus varices (the cause of which was not known). Also as of 2009, two French people, reported at ages 6 and 22 in 2003, were in excellent health without new physical problems and without progression of existing signs and symptoms.

While some features of NCBRS are always present, there is variability, and the severity of features may range from mild to severe. Therefore, the long- term outlook (prognosis) may vary among affected people.

Certain features of NCBRS can change or be progressive over time:

  • Scalp hair is usually sparse at birth and usually becomes increasingly sparse with age, particularly in the second decade of life. However in some, the sparseness improves with time.
  • Facial characteristics typically become more pronounced with increasing age. In some affected adults, the lower third of the face becomes markedly broad.
  • As people with NCBRS age, the amount of subcutaneous fat tissue tends to decrease, making the skin below the eyes sagging and wrinkled, especially at the cheeks when smiling. However, some affected people retain full cheeks.
  • The distal phalanges widen with age, becoming oval shaped and broad. Increasing space between the first and second toes can also occur over time.
  • At first, finger mobility is normal (maybe even hypermobile). Later on mobility often decreases, and some older people dislike passive movements of their fingers.
  • Osteoporosis is not uncommon and affected people may develop fractures in puberty or thereafter.
  • Although psychomotor regression is not typical, the high incidence of seizures that progressively worsen has been associated with loss of speech.

Last updated on 05-01-20

Name: American Association on Intellectual and Developmental Disabilities 501 3rd Street NW Suite 200
Washington, DC, 20001, United States
Phone: (202) 387-1968 Toll Free: (800) 424-3688 Fax : (202) 387-2193 Url: http://www.aaidd.org
Name: Genetic Disorders UK United Kingdom Toll Free: 0800 987 8987 Url: http://www.geneticdisordersuk.org/
Name: NCBRS Parent Support (for Nicolaides-Baraitser syndrome) Email: http://www.ncbrs.com/connect Url: http://www.ncbrs.com/

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The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

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