Introduction

Floating Harbour syndrome is a very rare congenital disorder with characteristic facial features, abnormal speech development (a high-pitched nasal voice), and many developmental dysfunctions, affecting all aspects of the affected child’s life.¹ Understanding the condition and the challenges that occur with it can help create a holistic care plan for the individual, involving their guardians and improving quality of life. This article focuses on one of the challenging symptoms of the disease, hearing impairment.

Understanding Floating Harbour Syndrome

With only about 100 documented cases in the world, Floating Harbour syndrome (FHS) is a rare genetic disorder. It is caused by spontaneously occurring mutations of the SRCAP gene which is responsible for the development of musculoskeletal structures, especially in the face. This mutation can be transferred within families in an autosomal dominant pattern, meaning that affected individuals’ offspring have a 50% chance of having the condition.^1,2

Symptoms

Floating Harbour syndrome presents with characteristic symptoms with varying severities in different individuals. Based on the degree of severity individuals may present with:

• Short stature: children with FHS are shorter than their peers
• Delayed speech and expressive language development: this may be due to abnormal anatomy of the voice box and surrounding structures. The voice is high-pitched and nasal
• Distinct facial features: triangular-shaped face with a broad and prominent nose, deep-set eyes and a thin upper lip
• Hearing impairment: this could be due to scarring of the structures in the ear due to recurrent infections (glue ear)
• Intellectual disability: mild to moderate
• Behavioural issues: inattention, impulsivity, hyperactivity, which may get better in adulthood
• Dental issues: delayed loss of baby teeth, extra teeth, and abnormally small teeth^1,2

Diagnosis

A team of experienced clinicians is involved in the diagnosis of Floating Harbour syndrome, including doctors and surgeons from various specialities including ENT, paediatricians, geneticists and others.²

• The clinician will take a detailed medical history, examine the child for characteristic features and collect information about the child’s growth and development²
• Some scans or assessments may be done to assess the changes in the anatomical structures of the ear, nose, back of the nose and throat. This could be a flexible nasal endoscopy, examining the ear under the microscope or an imaging scan²
• Genetic tests may be considered for couples that are affected or have a family history of the condition and are planning to conceive a child²

Early detection is key to being better prepared for managing the condition and creating an appropriate care plan for the child and their support network.

Hearing impairment and why it occurs

Hearing loss is one of the significant symptoms of Floating Harbour syndrome. A majority of affected children present with some form of hearing loss, either since birth, or progressively worsening impairment as the child grows older. One of the contributing factors is the abnormal anatomy of the ear canal making it susceptible to repeated ear infections. Sometimes, it is caused due to anatomical anomalies in the delicate structures of the inner ears.³

Types of hearing loss

Three types of hearing loss are commonly seen in individuals depending on the structures causing it. So the best way to understand hearing loss is by looking at a quick recap of the anatomy of the ear. The ear has three parts:

• Outer ear: the external part of the ear including the ear canal and the tympanic membrane that vibrates due to frequencies of sounds the pinna picks up⁴
• The middle ear: the bones of the ear (malleus, incus and stapes, that pick up signals from the tympanic membrane and amplify them)⁴
• The inner ear: consists of fine hair cells in the cochlea that pick up vibrations amplified in the middle ear and convert them into signals that can be processed by the brain⁴

The nerves pick up these signals from the inner ear and transfer them to appropriate areas in the brain made for processing and understanding sounds.⁴

Hearing loss can result in damage to the anatomy of the ear structures (conductive hearing loss) or due to problems with the nerves of the ear (sensorineural hearing loss).

• Conductive: caused by damage to the anatomy of the ear especially the tympanic membrane or the bones of the ear. This can be due to:
  • Repeated infections in the ear (acute otitis media) can result in scarring of the eardrum
  • Perforations in the eardrum cause damage to the inner structures especially the bones
  • Congenital malformations resulting in deformed structures in the middle ear. Sometimes it can make the person more prone to ear infections (like in Floating Harbour syndrome)⁵
• Sensorineural: hearing loss due to damage of the nerve present in the ear. It is challenging to treat this type of hearing loss. This can happen spontaneously, due to genetic factors or certain conditions that affect the nerves. It's less common in floating harbour syndrome⁵
• Mixed: some individuals present with complex hearing loss with features of both conductive and sensorineural hearing loss⁵

Impact of hearing on development

Hearing loss has profound implications on a child’s development, intellectually and socially. Some of the struggles children face include:

• Delayed speech development and communication issues
• Learning difficulties and difficulty in processing information academically
• Social and emotional development is affected leading to isolation, low self-esteem and potentially developing mental disorders from a young age⁵

Early detection of hearing impairment is crucial. The NHS newborn hearing-screening Program (NHSP) is a good way to track the child's hearing (if Floating Harbour syndrome is suspected).⁵

Management of hearing loss

Based on the type of hearing loss diagnosed there are various ways to manage it. After a thorough audiology and clinical assessment of the child your healthcare provider will assess the best possible course of action.

Conductive hearing loss

• Treating infections: Repeated otitis media, also known as glue ear, can result in the formation of pus behind the eardrum. If left untreated, this can result in scarring of the delicate structures behind the eardrum, thickening of the eardrum itself and potentially a perforation (which would present with significant discharge from the ear). Infections can be treated by:
  • Antibiotic and steroid drops
  • Maintaining ear hygiene
    • No water in the ear
    • Cotton ball generously coated in petroleum jelly before showering
    • Avoiding usage of cotton buds in the ear
  • Surgery: insertion of grommets (ventilation tubes in the eardrum to drain pus) if infections keep recurring. The ENT surgeons would do this⁶
• Surgical reconstruction of the middle ear bones: The malleus, incus and stapes, could be deformed, absent or separated from each other resulting in loss of conduction of sound vibrations. These could be reconstructed surgically⁶
• Hearing aids: in some cases, the anatomical abnormalities are too severe to be treated surgically and hearing aids are used to resolve the issue. Paediatric audiologists are trained to assess each case and recommend the right type of hearing aid based on the child’s symptoms and anatomy⁶

Sensorineural hearing loss

Sensorineural hearing loss is often treated by medications (sometimes steroids) and hearing aids. Some surgeries like cochlear implants can be helpful in certain cases.⁶

The medical team

Floating Harbour Syndrome is a complex condition with symptoms affecting all aspects of the child’s life, hearing being one of them. A team of various specialists will be involved in the child’s and their guardian’s lives. From a hearing perspective the multidisciplinary team you would be exposed to (but not limited to) the following specialities:

• Audiologists: Audiologists first test the hearing and chart it. They also examine the ear canal with an otoscope or sometimes a microscope to visualise the ear canal and the tympanic membrane (looking for ear wax, or signs of infections)⁶
• ENT specialists: ENT doctors examine the person, assess their symptoms, examine the person and create and implement a curative management plan. This may involve ear drops and surgery (grommets)⁶
• Speech and Language Therapists (SALT): Assisting with improving speech, tone of voice and communication skills⁷
• Educational support: Children need additional support with learning, especially with hearing impairments. Additionally, if the child has additional learning disabilities and behavioural issues associated with Floating Harbour Syndrome, they may have to be in schools tailored to their unique needs so that they can achieve their full potential⁷

Early intervention in children with FHS is key, especially from the hearing loss aspect. Associated hearing is treatable in the majority of the cases, it is a matter of proactively getting the support you need through the right sources. While the hearing may not be perfect, they significantly improve the quality of life.

Key takeaways

• Floating Harbour syndrome is a rare congenital disorder with roughly 100 cases documented in research. The disease occurs due to a mutation in the SRCAP gene and can be transmitted through families in an autosomal dominant pattern
• Symptoms include changes in facial structures including a characteristic broad and long nose, triangular face, deep-set eyes, thin upper lip and short stature
• One of the challenging symptoms of the condition is hearing impairment and delayed speech and language development
• There are three major types of hearing loss: conductive (issues with the anatomical structures in the middle ear and eardrum), sensorineural (dysfunction of the nerves that process sound) and mixed (features of both types)
• Floating Harbour syndrome is characterised by conductive hearing loss due to damage of the structures in the ear due to recurrent infections (otitis media) or deformities in the bony structures of the middle ear
• A team of audiologists, ENT specialists and Speech and Language Therapists manages hearing loss.
• Treatment of ear infections involves antibiotic ear drops, maintaining ear hygiene and sometimes surgery (grommets or ventilation tubes in the ear drums). Surgery may be required to reconstruct the bones of the middle ear if needed
• Hearing aids are fitted in most cases based on the severity of hearing loss and the effectiveness of other treatments
• Early intervention and a good support system are key to effective management of hearing loss and improving quality of life

FAQs

What is the prognosis of Floating-Harbour Syndrome?

The prognosis of Floating-Harbour Syndrome varies depending on the severity of the symptoms and the effectiveness of interventions. Generally, individuals with Floating-Harbour Syndrome have a normal life expectancy. However, they may face ongoing challenges related to developmental delays, hearing impairment, and other associated features.^1,2

Is Floating-Harbour Syndrome genetic?

Yes, Floating-Harbour Syndrome is genetic. It is caused by mutations in the SRCAP gene, which is inherited in an autosomal dominant pattern. Genetic testing can confirm the presence of these mutations and provide information about inheritance patterns.^1,2