Introduction

Floating-Harbor syndrome¹ is a rare genetic disorder caused by an autosomal dominant mutation, inherited from one of the parents. This syndrome was first discovered in 1973 in two patients, one at the Boston Floating Hospital and the other at the Harbor General Hospital, both in the USA, which was how the name “floating-harbor” came into existence.

The features of Floating-Harbor syndrome include short stature with delayed bone growth, retarded speech development, intellectual disability and distinctive facial malformations. These facial features often include a triangular face, long eyelashes, a wide columella (the tissue that separates the nostrils), a flat midface, and a thin upper lip.

This article aims to explore the diagnosis and diagnostic criteria for Floating-Harbor syndrome and the importance of accurate diagnosis in managing and treating Floating harbour syndrome.¹

Keywords

• Autosomal: Related to regular chromosomes, not sex chromosomes
• Dominant: A trait that shows up even if only one copy is present
• Mutation: A change in the DNA
• Malformation: An unusual or wrong shape of a body part
• Columella: The small part in the middle of the nose
• Philtrum: The groove between the upper lip and nose

Cause

Floating harbor syndrome² is caused by a mutation in the SIRCAP gene. Genes contain proteins which determine our features such as height, colour, size and shape.

Mutation in the gene may cause part of the proteins to become inefficient or absent. These changes might affect many organs and systems in the body.

Although many cases of Floating Harbour syndrome occur as a result of sporadic mutation(i.e. they occur on their own), there are very few cases where it can be inherited either from the father or mother.²

Diagnosis

The diagnosis² of floating harbour syndrome is based on the identification of characteristic symptoms. A detailed patient history, thorough clinical analysis and a variety of specialized tests are requested. 

Characteristic symptoms

Floating harbour syndrome can be suspected when these physical features are seen in an individual. These features include:

• Triangular-shaped face
• A deep set of eyes
• Wide mouth with thin upper lip
• Long nose with a narrow bridge, broad base, broad tip, and low-hanging columella
• Low set ears
• Significant delay in bone growth
• Short stature
• Difficulty in speaking clearly and understanding already established language(s)
• Intellectual impairment

Patient history

To take a patient's history means to gather all the information about a patient's past and present health. It involves asking questions to know the patient's symptoms, medical background, medications, allergies, lifestyle, family history, and other factors that could influence their health.

This allows health providers to understand the patient's condition, identify points where the patient is at risk and also make the appropriate decision on the kind of care to be given.

Clinical analysis

Clinical analysis involves the use of testing outcomes obtained from various testing procedures to make conclusions on the diagnosis, treatment plan and overall health management of a patient.

Testing procedures

There are different forms of disorder that appear to have the same symptoms as Floating Harbor syndrome. Various molecular gene testing³ processes can be used to establish the diagnosis of the syndrome.

These procedures include:

• Targeted gene sequencing
• Whole exome sequencing
• Copy number variation analysis
• Whole genome sequencing
• RNA sequencing

Diagnostic criteria

Diagnostic criteria are specific clinical, laboratory and imaging investigations carried out to ensure that the correct diagnosis is obtained for a particular disease. There are specific conditions that must be seen before it can be called a floating harbour syndrome.

The reason for setting a criteria is because there are other conditions which show similar signs with Floating Harbor syndrome in early childhood stages. These early childhood signs of Floating Harbor syndrome can become less prominent as the child grows hence the need for differential diagnosis.³

Examples of such syndromes include; Three M syndrome,⁴ Rubinstein-Taybi syndrome,⁵ FOXP2 speech and language disorder⁶ and Silver-Russell syndrome.⁷

The importance of accurate diagnosis in the management and treatment of floating harbour syndrome

The accurate diagnosis of Floating Harbor Syndrome is necessary for it to be properly treated and managed, ensuring that patients receive the most appropriate care and interventions tailored to their specific needs.

The reasons for accurate diagnosis include;

Personalized treatment plans: Health providers always encounter different patients with different needs that are specific to them. An accurate diagnosis allows for a well-developed treatment plan to suit each patient according to their treatment needs.

To avoid misdiagnosis: The Floating Harbor syndrome shares similar symptoms with other syndromes such as Three M syndrome, Rubinstein-Taybi syndrome, FOXP2 speech and language disorder and Silver-Russell syndrome. Therefore, it is important for accurate diagnosis to be done to avoid inappropriate treatments or interventions that may not benefit the patient.

Improved quality of life: Accurate diagnosis will help individuals with Floating Harbor syndrome to receive appropriate medical, educational, and social support, their families will also have access to resources and care needed to manage the syndrome effectively.

Summary

Floating-Harbor Syndrome is a rare genetic disorder characterized by distinct facial features, delayed bone growth, speech difficulties, and intellectual impairment. It is caused by mutations in the SIRCAP gene which can be inherited or occur sporadically on its own.

In order to give good treatment and management, accurate diagnosis has to be done. To achieve an accurate diagnosis, the patient history will be collected and physical examination alongside other clinical analyses using specialized molecular tests will be used to distinguish Floating Harbour syndrome from similar syndromes.

Correct diagnosis enables personalized treatment plans, prevents misdiagnosis, and improves the quality of life for patients and their families.

This article seeks to show the diagnosis and diagnostic criteria for floating-harbor syndrome and the importance of accurate diagnosis in managing and treating Floating harbour syndrome.