In 1974, a patient seen at the Harbor General Hospital (Torrance, California, U.S.A.) was found to share an undiagnosed and astonishingly unique set of symptoms with a patient seen just one year earlier, at the Floating Hospital (Boston, U.S.A.).^1,2 These symptoms were recognised as belonging to a new disorder, which was named as Floating-Harbor Syndrome (FHS); this name, ofcourse, was derived from the hospitals at which the first two cases of the disorder were seen.^3,4,5 Since then, FHS has proven itself to be an extremely rare genetic disorder with only about 100 (>100) cases ever having been reported.^6,7

FHS is caused by a mutation in the SRCAP gene of our DNA.^8,9 In simple terms, that just means that FHS is caused by a change to a certain section of the chemical code in our cells. This code (DNA) is, itself, an actual chemical which contains the information necessary for our cells to build various proteins. Different sections (or genes)  of DNA are responsible for coding for different proteins, and if these genes change, then the proteins, which they are responsible for, may be built incorrectly. Consequently, mutations can cause these altered proteins to fail to perform their usual roles in various body processes and/or structures. In FHS, this mutation is responsible for a number of symptoms, including delayed speech development, short height, and distinct facial features.^10,11,12 To find out more regarding the skeletal abnormalities associated with FHS, please read on. 

Skeletal abnormalities 

There is are range of skeletal abnormalities which may be associated with FHS:^{4,5,7,13,14,15,16,17,18,19,20,21,22,23}

Growth/General  

• Short height
• A short neck
• A broad chest
• Low birth weight
• Low birth length 
• Delayed bone age
• Joint laxity/hypermobility
• Hip dysplasia

Facial structure 

• A triangular face
• Deep-set eyes
• A prominent nose with a broad tip
• A small head
• A bulging and narrow forehead 

Fingers and toes

• Clinodactyly: an abnormally curved finger
• Syndactyly: webbed toes or fingers
• Brachydactyly: disproportionately short fingers or toes
• Nail clubbing
• Dystrophic toenail; discoloured, thickened or deformed toenail

Dental

• Macrodontia; some teeth are growing more than they should
• Microdontia: some teeth grow less than they should
• Micrognathia; small lower jaw
• Malocclusion: misaligned teeth
• Oligodontia; absence of 6 or more teeth from birth

Other symptoms

Development

• Cryptorchidism; undescended testicles
• Hypospadias, where the opening of the urethra is located in the wrong part of the penis
• Heavy periods
• Hirsutism: excessive hair growth in areas of the body where it's usually minimal
• Sparse hair

Facial features

• Short philtrum (the vertical indentation in the middle area above the upper lip, which connects to the nose)
• Wide columella (the bridge of tissue that separates the nostrils at the bottom of your nose)
• Long eyelashes
• Low set ears, rotated rearwards
• Broad mouth, sometimes with downturned corners
• Ear/skin tag
• Cleft lip/palate
• Incomplete folding of the ears
• Thin (upper) lip(s) 

Wider health complications 

• Atrial septal defect (a hole between the chambers of the heart)
• Coeliac disease
• Abdominal distention (swelling

Neuropsychological Symptoms

Furthermore, there are a number of neurological issues which may affect someone with FHS:^4,13,23,24

Speech

• Delays in speech development
• Hypernasality
• Ankyloglossia: limited tongue mobility
• Apraxia of speech
• Problems with articulation
• Developmental aphasia

Behaviour

• Attention deficits
• Anxiety
• Depressive symptoms
• Loss of appetite
• Tantrums
• Impulsiveness

Others

• Seizures
• Impaired/delayed motor skills; this may also play a part in speech deficits
• Visuospatial impairment
• Visuoconstructive apraxia; difficulty in assembling objects, drawing, or copying designs
• Mild deficits in cognitive skills
• Impaired visual and verbal memory

Summary

Floating-Harbour Syndrome (FHS) is an exceptionally rare genetic disorder first identified in two patients in the early 1970s at Harbour General Hospital (Torrance, California, U.S.A.) and Floating Hospital (Boston, U.S.A.), from which the syndrome derives its name. FHS is caused by a mutation in the SRCAP gene, which leads to changes in the DNA responsible for coding essential proteins. This mutation results in a unique set of symptoms, including delayed speech development, short stature, and specific facial features such as a triangular face, deep-set eyes, and a prominent nose. Other physical characteristics may include a short neck, a broad chest, and dental anomalies like macrodontia and micrognathia. Additionally, individuals with FHS may experience neurological challenges, including attention deficits, anxiety, and mild cognitive impairments. So far, slightly more than 100 cases have been reported.

Frequently asked questions 

What is floating-harbour syndrome?

Floating-Harbour Syndrome (FHS) is a very rare genetic disorder first identified in the 1970s. It is caused by a mutation in the SRCAP gene, which affects the body's ability to produce certain essential proteins. This leads to a unique set of symptoms, including delayed speech development, short stature, and distinctive facial features.

How is floating-harbour syndrome inherited? 

Floating-Harbour Syndrome is usually caused by a new mutation in the SRCAP gene, which means it often occurs randomly and is not always inherited from a parent. However, in rare cases, it can be passed down from an affected parent to their child.

What are the key symptoms to look out for? 

Key symptoms of FHS include delayed speech development, short height, and specific facial features such as a triangular face, deep-set eyes, and a prominent nose. Other signs can include dental anomalies, attention deficits, and anxiety, as well as many others..

Can floating-harbour syndrome be cured?  

Currently, there is no cure for Floating-Harbour Syndrome. Treatment focuses on managing the symptoms and providing support to help individuals live a full life. This may include speech therapy, special education, and medical care for any associated health issues.

What is the life expectancy of someone with floating-harbour syndrome?**  

While FHS can present various challenges, most individuals with the syndrome have a normal life expectancy. However, the quality of life can be improved with appropriate medical care and support.

How can families support a child with floating-harbour syndrome? 

Families can support a child with FHS by working closely with healthcare professionals to address the child's specific needs. This may involve regular medical check-ups, speech therapy, and creating a supportive and understanding environment at home and school.