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Genetics Home Reference: your guide to understanding genetic conditions
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Floating-Harbor syndrome

Reviewed December 2012

What is Floating-Harbor syndrome?

Floating-Harbor syndrome is a disorder involving short stature, slowing of the mineralization of the bones (delayed bone age), delayed speech development, and characteristic facial features. The condition is named for the hospitals where it was first described, the Boston Floating Hospital and Harbor General Hospital in Torrance, California.

Growth deficiency in people with Floating-Harbor syndrome generally becomes apparent in the first year of life, and affected individuals are usually among the shortest 5 percent of their age group. Bone age is delayed in early childhood; for example, an affected 3-year-old child may have bones more typical of a child of 2. However, bone age is usually normal by age 6 to 12.

Delay in speech development (expressive language delay) may be severe in Floating-Harbor syndrome, and language impairment can lead to problems in verbal communication. Most affected individuals also have mild intellectual disability. Their development of motor skills, such as sitting and crawling, is similar to that of other children their age.

Typical facial features in people with Floating-Harbor syndrome include a triangular face; a low hairline; deep-set eyes; long eyelashes; a large, distinctive nose with a low-hanging separation (overhanging columella) between large nostrils; a shortened distance between the nose and upper lip (a short philtrum); and thin lips. As affected children grow and mature, the nose becomes more prominent.

Additional features that have occurred in some affected individuals include short fingers and toes (brachydactyly); widened and rounded tips of the fingers (clubbing); curved pinky fingers (fifth finger clinodactyly); an unusually high-pitched voice; and, in males, undescended testes (cryptorchidism).

How common is Floating-Harbor syndrome?

Floating-Harbor syndrome is a rare disorder; only about 50 cases have been reported in the medical literature.

What genes are related to Floating-Harbor syndrome?

Floating-Harbor syndrome is caused by mutations in the SRCAP gene. This gene provides instructions for making a protein called Snf2-related CREBBP activator protein, or SRCAP. SRCAP is one of several proteins that help activate a gene called CREBBP. The protein produced from the CREBBP gene plays a key role in regulating cell growth and division and is important for normal development.

Mutations in the SRCAP gene may result in an altered protein that interferes with normal activation of the CREBBP gene, resulting in problems in development. However, the relationship between SRCAP gene mutations and the specific signs and symptoms of Floating-Harbor syndrome is unknown. Rubinstein-Taybi syndrome, a disorder with similar features, is caused by mutations in the CREBBP gene itself.

Related Gene(s)

Changes in this gene are associated with Floating-Harbor syndrome.

  • SRCAP

How do people inherit Floating-Harbor syndrome?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

Most cases of Floating-Harbor syndrome result from new mutations in the gene and occur in people with no history of the disorder in their family. However, in some cases an affected person inherits the mutation from one affected parent.

Where can I find information about diagnosis or management of Floating-Harbor syndrome?

These resources address the diagnosis or management of Floating-Harbor syndrome and may include treatment providers.

  • Gene Review: Floating-Harbor Syndrome (http://www.ncbi.nlm.nih.gov/books/NBK114458)
  • Genetic Testing Registry: Floating-Harbor syndrome (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0729582)
  • KidsHealth: Bone Age Study (http://kidshealth.org/parent/system/medical/xray_bone_age.html)

You might also find information on the diagnosis or management of Floating-Harbor syndrome in Educational resources (http://www.ghr.nlm.nih.gov/condition/floating-harbor-syndrome/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/floating-harbor-syndrome/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about Floating-Harbor syndrome?

You may find the following resources about Floating-Harbor syndrome helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for Floating-Harbor syndrome?

  • FHS
  • FLHS
  • Leisti-Hollander-Rimoin syndrome
  • Pelletier-Leisti syndrome

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about Floating-Harbor syndrome?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding Floating-Harbor syndrome?

autosomal ; autosomal dominant ; brachydactyly ; cell ; clinodactyly ; cryptorchidism ; deficiency ; disability ; gene ; inherited ; motor ; mutation ; philtrum ; protein ; short stature ; stature ; syndrome ; testes

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Arpin S, Afenjar A, Dubern B, Toutain A, Cabrol S, Héron D. Floating-Harbor Syndrome: report on a case in a mother and daughter, further evidence of autosomal dominant inheritance. Clin Dysmorphol. 2012 Jan;21(1):11-4. doi: 10.1097/MCD.0b013e32834af5a7. (http://www.ncbi.nlm.nih.gov/pubmed/21955542?dopt=Abstract)
  • Asseidat I, Kaufman LM. Ocular abnormalities in Floating-Harbor syndrome. J AAPOS. 2009 Apr;13(2):218-20. doi: 10.1016/j.jaapos.2008.11.002. (http://www.ncbi.nlm.nih.gov/pubmed/19393524?dopt=Abstract)
  • Hood RL, Lines MA, Nikkel SM, Schwartzentruber J, Beaulieu C, Nowaczyk MJ, Allanson J, Kim CA, Wieczorek D, Moilanen JS, Lacombe D, Gillessen-Kaesbach G, Whiteford ML, Quaio CR, Gomy I, Bertola DR, Albrecht B, Platzer K, McGillivray G, Zou R, McLeod DR, Chudley AE, Chodirker BN, Marcadier J; FORGE Canada Consortium, Majewski J, Bulman DE, White SM, Boycott KM. Mutations in SRCAP, encoding SNF2-related CREBBP activator protein, cause Floating-Harbor syndrome. Am J Hum Genet. 2012 Feb 10;90(2):308-13. doi: 10.1016/j.ajhg.2011.12.001. Epub 2012 Jan 19. (http://www.ncbi.nlm.nih.gov/pubmed/22265015?dopt=Abstract)
  • Lacombe D, Patton MA, Elleau C, Battin J. Floating-Harbor syndrome: description of a further patient, review of the literature, and suggestion of autosomal dominant inheritance. Eur J Pediatr. 1995 Aug;154(8):658-61. Review. (http://www.ncbi.nlm.nih.gov/pubmed/7588969?dopt=Abstract)
  • Nelson RA, McNamara M, Ellis W, Stein-Wexler R, Moghaddam B, Zwerdling T. Floating-Harbor syndrome and intramedullary spinal cord ganglioglioma: case report and observations from the literature. Am J Med Genet A. 2009 Oct;149A(10):2265-9. doi: 10.1002/ajmg.a.33014. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19764022?dopt=Abstract)
  • Patton MA, Hurst J, Donnai D, McKeown CM, Cole T, Goodship J. Floating-Harbor syndrome. J Med Genet. 1991 Mar;28(3):201-4. (http://www.ncbi.nlm.nih.gov/pubmed/2051457?dopt=Abstract)
  • White SM, Morgan A, Da Costa A, Lacombe D, Knight SJ, Houlston R, Whiteford ML, Newbury-Ecob RA, Hurst JA. The phenotype of Floating-Harbor syndrome in 10 patients. Am J Med Genet A. 2010 Apr;152A(4):821-9. doi: 10.1002/ajmg.a.33294. (http://www.ncbi.nlm.nih.gov/pubmed/20358590?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: December 2012
Published: October 20, 2014