Introduction

Floating Harbour Syndrome (FHS) is a rare genetic condition, characterized by facial abnormalities, short stature, and delayed language development. This condition is so rare, and its symptoms so variable, that less than 100 confirmed cases of FHS have been recorded in media to date.¹ The disease acquired its name from the two hospitals where it was first described in the early 1970s: Boston Floating Hospital and Harbour General Hospital in California.² FHS symptoms can start to become apparent as early as infancy and early diagnosis is crucial in affecting long-term disease prognosis. This article aims to provide information on the long-term impacts of Floating Harbour Syndrome and the role that early diagnosis plays in affecting this impact. Educating detail will first be provided on the specific characteristics of the disease followed by prognosis, general quality of life expectancy, and management strategies. 

Clinical features of floating harbour syndrome

The typical facial symptoms associated with Floating Harbour Syndrome usually start to become apparent from birth, a triangular face, a bulbous nose, deep-set eyes with long eyelashes, a low hairline and thin lips. As children age, their nose tends to grow in size in a disproportional manner to the rest of their facial structure.³ Developmental growth delay typically becomes apparent in the first 6 years of the child's life where they will likely always fall in the lowest 5 percent of their age group. However, this tends to regulate by the time the child is between the ages of 6 and 12, making it a characteristic feature only during early diagnosis. Although speech deficits are considered characteristic of FHS, there is no generally accepted consensus on the exact nature of these language problems. Of the few case studies recorded, many have varying cognitive issues that affect their speech development and communication skills.⁴ Another symptom that is common but not always present for individuals with FHS is having abnormally short fingers and toes known as Brachydactyly. These digits are often also squared off at the ends, giving the impression of being clubbed.² 

Cause and diagnosis of FSH

FHS is caused by a genetic mutation in the gene SRCAP and is an autosomal dominant disorder. This means that inheriting just one copy of the faulty gene from either parent is enough to cause the disorder in the child. Due to this inheritance, the disease is commonly seen running in families but the exact cause of the mutation remains unknown up to date.¹ Typical diagnosis of FHS starts with the identification of FHS-specific symptoms characterised above. To confirm diagnosis, genetic testing is done on the child’s genotype to confirm a faulty version of their SRCAP gene.⁵

Prognosis and treatment of FSH

Due to the rarity of the disease and the variable impacts that the symptoms have on affected individuals, an estimate of life expectancy for those with FHS is difficult to obtain. However, studies indicate that those with FHS may have a normal life expectancy.⁶ Although there is no cure for FHS at present, there are many treatment options that can significantly improve a patient’s quality of life if implemented early enough. 

Growth outcomes

The short stature associated with FHS is the most characteristic feature of the disease. Children with FHS usually also have a lower bone age than is regular up until puberty. In a few cases, these developmental issues self-regulate and the child catches up to a normal height for their age by the time puberty occurs. However, treatment with recombinant human Growth Hormone (rhGH) has shown much promise for treatment in this area. The effects of rhGH treatment for growth regulation were ascertained by assessing 22 children with FHS who had received this treatment. Most of these children responded well to rnGH and showed a positive height change without adverse effects. However, three of the children showed beyond-normal acceleration of bone density after puberty.⁷ Another case study of a 7-year-old girl with FHS showed similar results in that rnGH treatment regulated her height and allowed her to reach normal bone age by 12 but her bone age was seen to rapidly increase after puberty. At present, not enough studies have been done to confirm whether this abnormal increase in bone age is a result of the rhGH treatment or a normal outcome of FHS.⁸

Cognitive and intellectual outcomes

A review was done on 52 patients of varying ages with FHS and revealed great insight into the cognitive effects of the disease. In terms of cognition, children ranged from having an IQ within the normal range of 104 to having severe intellectual impairments in some cases. However, research has indicated that all individuals with FHS suffer some form of intellectual impairment. It was also common to see children with FSH being diagnosed with other disabilities such as attention deficit hyperactivity disorder (ADHD) and compulsive skin picking.⁹ Although the cognitive effects of the disease vary, health professionals agree that early intervention is crucial for managing all intellectual difficulties. Most children with FSH will benefit from occupational and speech therapy as well as other special learning schools that cater to their needs.⁵ Research indicates that with the appropriate early intervention, a high quality of life can be achieved for individuals with Floating Harbour Syndrome. 

Secondary health problems

Although the prognosis is positive for individuals with FHS to be able to enjoy a high quality of life, secondary health complications that are associated with FHS need to be taken into account and monitored regularly. Some of the associated health conditions that have been reported are congenital heart defects, high blood pressure in adults and underactive thyroid glands.² To mitigate the risks that come with these adverse secondary health problems, comprehensive and regular health checks are recommended for the best prognosis outcome. 

The role of genetic counselling 

Genetic counsellors perform a vital role in helping families to understand the medical, psychological, and physical impacts that a disease can have. This information helps families to better understand FHS and make appropriate decisions for better management of the disease.¹⁰ This can help families make informed medical decisions that will improve the quality of life for the individual with FHS. Moreover, genetic counsellors can direct the family to specialists who can further support their child’s specific needs. Supporting a child with special needs can also be incredibly emotionally taxing for parents and genetic counsellors can also direct the family towards resources such as support groups that can provide a community.

Genetic counsellors can also serve to provide a comprehensive risk assessment for couples wanting to conceive but concerned with the risk of passing FHS on to their child. Although most cases of FHS arise through de novo mutation, meaning there is no heritability of the disease, there are some instances where inheritance is possible. Therefore, if there is a known member of the family with FHS it is recommended to consult genetic counseling for further testing that can ascertain the risk of this disease being passed on to offspring. This can allow aspiring parents to fully consider their options once knowing the likelihood of disease transmission.⁵

The role of advocacy and awareness

With the number of individuals affected by FHS being so few, patient advocacy and increasing awareness of the disease are more important than ever. Increasing awareness of the disease increases the likelihood that patients will receive early diagnosis and promotes the likelihood of patients having access to high-quality care.¹¹ Moreover, rare disease patients have a unique opportunity to take part in and form Patient Advocacy Groups (PAGs) which serve not only to educate the public about the disease but also to share experiences with fellow patients, compare resources and create a strong sense of community.¹² 

Summary

Floating Harbour Syndrome is a rare disease characterized by short stature, intellectual impairments and facial abnormalities. Although no cure is available at present, patients have a positive prognosis and have been seen to live long high-quality lives. However, early diagnosis of the disease is crucial in determining quality of life as this allows for appropriate learning and developmental resources to be fully utilized. Both genetic counselling and general patient advocacy and awareness are instrumental in promoting the early detection of this disease and its appropriate management.