What Causes Floating-Harbor Syndrome?

Although researchers have established core symptoms, much about the condition remains unknown. Several constraints, including the small number of identified cases, the absence of major clinical investigations, and the potential of additional genes impacting the condition, hinder clinicians from getting a comprehensive picture of the disorder.

Facial abnormalities are the defining aspect of this disease.

Signs and symptoms of Floating-Harbor syndrome

• Facial features
  • Deep-set eyes
  • Triangular face
  • Wide mouth with a thin vermilion border on the upper lip
  • Long nose with a narrow bridge and broad, bulbous base
  • Low-set ears
  • Abnormally long eyelashes
  • Thin lips
  • A broad, linear mouth
  • A prominent, triangular-shaped nose
• Voice quality and language
  • Dysarthria (difficulty speaking)
  • Verbal dyspraxia (difficulty or inability to coordinate the precise movements required to produce clear speech)
  • Hypernasality
  • High-pitched voices
  • Severe receptive and expressive language impairment
• Bodily features
  • Significant delay in bone age
  • Skeletal anomalies
  • Short fingers and toes
  • Broad fingertips or clubbing
  • Short adult stature (average of 140 cm or less)
  • Delayed growth may lead to low birth weight
  • Broad fingertips that give the appearance of clubbing
  • Short, broad thumbs
  • Prominent joints
  • Abnormalities of the collarbones (clavicles)
  • Short neck
• Behavior
  • Unpredictable, aggressive outbursts
  • Tantrums during infancy
  • Hyperactivity
  • Impulsivity
  • Short attention span
  • Aggression
  • Anxiousness, repeated skin picking
  • Attention deficit-hyperactivity disorder during school years
  • Autistic spectrum disorder
  • Asperger syndrome
  • Obsessive-compulsive disorder (repeated skin picking)
• Other observations
  • Intellectual disability
  • Learning disability
  • Early entry into puberty
  • Dental problems 
  • Visual impairment
  • Backflow or leakage of the contents of the stomach into the esophagus (gastroesophageal reflux)
  • Farsightedness (hyperopia)
  • Crossed eyes (strabismus)
  • Recurrent middle ear infections (otitis media)
  • Conductive hearing loss
  • Kidney abnormalities, such as hydronephrosis (cysts or swelling in the kidneys due to the abnormal accumulation of urine, which is caused by a blockage in the urinary tract)
  • Undescended testicles
  • Celiac disease
  • Congenital heart defects
  • Underactive thyroid functions
  • Hypertension
  • Delayed skull formation
  • Mental retardation (takes longer to learn and build new skills)
  • Cognitive impairment

Floating-Harbor syndrome causes a wide range of symptoms. The person’s short stature is especially noticeable in most cases; they grow to a height of 140 cm or less.

The typical anatomical anomalies of Floating-Harbor syndrome frequently indicate the presence of the disease. Most complaints are at birth or a young age. The malformations in the child are apparent to doctors and parents, prompting appropriate examinations. Molecular genetic testing with facial symptoms confirms the diagnosis of Floating-Harbor syndrome.

Diagnosing Floating-Harbor syndrome

• Physical and medical history:
  • The attending physician analyzes the symptoms and medical history and possible causes of the disease during the first consultation.
  • Because Floating-Harbor syndrome is a genetic disease, family history is crucial.
  • The malformations of the face indicate the disease.
• Imaging studies: X-ray technical studies reveal the major delay in bone age.
• Molecular genetic testing:
  • Detects genetic mutations. A sequence analysis test can detect mutations in the SRCAP gene.
  • If the person exhibits classic facial features of Floating-Harbor syndrome, molecular testing will reveal a mutation in the SRCAP gene.
• Prenatal diagnosis: Prenatal diagnosis could be possible for families with a known SRCAP gene mutation. DNA extracted from fetal cells can help identify the disease-causing mutation.
• Pre-implantation genetic diagnosis (PGD):
  • Could be an option if one of the parents has a known genetic abnormality.
  • Performed on embryos created through in vitro fertilization.
  • Examines an embryo to see if it has the same genetic abnormality as its parent. Families considering this option should seek the advice of a certified genetics professional.

Floating-Harbor syndrome has no known cure. Managing the symptoms and features entail keeping a close eye on the person’s physical and mental health.

Managing symptoms of Floating-Harbor syndrome

• Early developmental intervention is important to ensure that affected children reach their potential.
• Most affected children will benefit from occupational, physical, and speech therapy.
• Additional medical, social, and/or vocational services, including special remedial education, could be beneficial.
• Ongoing counseling and support for parents will help.
• Genetic counseling will benefit affected individuals and their families.
• Growth hormone therapy has been used to treat some individuals with Floating-Harbor syndrome.
• Additional therapies, along with standard treatment, may depend on specific symptoms.
• Clinical trials could be recommended for those who have a progressive condition

Floating-Harbor Syndrome is treated symptomatically. In most cases, the children affected receive special education and grants.

The prognosis of Floating-Harbor syndrome, which occurs rarely, is poor due to the severity of symptoms. Short stature, language difficulties, and changes in facial structure are common long-term effects of this syndrome. Because this disease is primarily genetic and congenital, only gene therapy could improve the prognosis of Floating-Harbor syndrome.

Development of appropriate therapies for Floating-Harbor syndrome is limited because the condition is rare. This worsens the prognosis.

Many have a relatively good life and, in some cases, can manage their daily lives independently. With age, facial abnormalities fade. Regular examinations could be required to correct the complications.