Individuals with Floating-Harbor syndrome are typically born with a low birth weight and normal head circumference. There are often feeding difficulties for the first few years of life with poor growth and persistent short stature (final adult height 140-155cm). Typical facial features include triangular facies, a broad-based long nose with narrow bridge and overhanging tip, deeply set eyes, low set ears and a short philtrum. Strabismus can be a feature as well as minor hearing and dental abnormalities.
Bone age is significantly delayed in early childhood but tends to normalise between the ages of 6-12 years. Skeletal abnormalities include brachydactyly, clinodactyly, prominent joints and swelling of fingertips (that appear clubbed), and short broad thumbs.
Speech development is delayed with often severely impaired expressive language, dysarthria and verbal dyspraxia, hypernasality and a high-pitched voice. Speech may be absent in some. Intellectual impairment is invariably present but typically ranges from mild to moderate. Initial developmental milestones in gross and fine motor domains are usually normal. There is often challenging behaviour with difficult temper tantrums in early childhood, ADHD spectrum disorders, and sometimes aggressive and violent episodes that can be difficult to manage.
Medical conditions associated with the condition include renal problems (cysts, hydronephrosis, agenesis), seizures, early puberty and gastro-oesophageal problems including gastro-oesophageal reflux and constipation.