Floating-Harbor syndrome

Floating-Harbor syndrome (FHS) is a rare genetic disorder named after the two hospitals where it was first described — Boston Floating Hospital and Harbor General Hospital in California. It is caused by mutations in the SRCAP gene (SNF2-related CREBBP activator protein) located on chromosome 16p11.2. This gene plays an important role in chromatin remodeling and transcriptional regulation, and pathogenic variants — typically truncating mutations in the last exon — lead to the characteristic features of the syndrome. The hallmark clinical features of Floating-Harbor syndrome include short stature with delayed bone age, significantly delayed speech and language development, and a distinctive facial appearance. Facial features typically include a triangular face, deep-set eyes, a long nose with a narrow bridge and broad tip, a short philtrum, thin lips, and low-set ears. Bone age is characteristically delayed in early childhood but tends to normalize or even advance by puberty. Expressive language is typically more severely affected than receptive language, and many individuals have mild to moderate intellectual disability, though the degree of cognitive impairment is variable. Additional features may include skeletal anomalies (such as short fingers, clinodactyly, and broad thumbs), feeding difficulties in infancy, constipation, hearing loss, and occasional congenital anomalies including renal and cardiac defects. Behavioral issues, including attention difficulties and anxiety, have also been reported. There is no specific cure for Floating-Harbor syndrome. Management is supportive and multidisciplinary, involving speech and language therapy, educational support, growth monitoring, and treatment of associated medical complications. Growth hormone therapy has been used in some cases, though its efficacy remains variable and not well established.

Common questions about Floating-Harbor syndrome