Floating-Harbor syndrome is a rare SRCAP-related autosomal dominant developmental disorder characterized by short stature, delayed bone age, severe language impairment, and a recognizable craniofacial phenotype. Available evidence supports dominant-negative SRCAP disruption with downstream chromatin and transcriptional dysregulation.
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name: Floating-Harbor syndrome
creation_date: "2026-04-15T15:45:03Z"
updated_date: "2026-04-15T18:55:00Z"
description: >-
Floating-Harbor syndrome is a rare SRCAP-related autosomal dominant
developmental disorder characterized by short stature, delayed bone age,
severe language impairment, and a recognizable craniofacial phenotype.
Available evidence supports dominant-negative SRCAP disruption with
downstream chromatin and transcriptional dysregulation.
category: Mendelian
parents:
- hereditary disease
disease_term:
preferred_term: Floating-Harbor syndrome
term:
id: MONDO:0007621
label: Floating-Harbor syndrome
inheritance:
- name: Autosomal dominant inheritance
description: >-
Floating-Harbor syndrome is inherited in an autosomal dominant manner, and
most affected individuals have a de novo SRCAP pathogenic variant.
inheritance_term:
preferred_term: Autosomal dominant inheritance
term:
id: HP:0000006
label: Autosomal dominant inheritance
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
GENETIC COUNSELING: SRCAP-FHS is inherited in an autosomal dominant
manner. The majority of affected individuals have a de novo pathogenic
variant.
explanation: This directly supports autosomal dominant inheritance in SRCAP-related Floating-Harbor syndrome.
pathophysiology:
- name: SRCAP truncation-driven chromatin dysregulation
description: >-
Floating-Harbor syndrome is caused by heterozygous truncating SRCAP
variants. Available review evidence supports a dominant-negative model with
disrupted chromatin-associated transcriptional control.
genes:
- preferred_term: SRCAP
term:
id: hgnc:16974
label: SRCAP
biological_processes:
- preferred_term: chromatin remodeling
modifier: ABNORMAL
term:
id: GO:0006338
label: chromatin remodeling
- preferred_term: regulation of transcription by RNA polymerase II
modifier: ABNORMAL
term:
id: GO:0006357
label: regulation of transcription by RNA polymerase II
evidence:
- reference: DOI:10.3389/fgene.2022.846101
reference_title: >-
Molecular Genetics and Pathogenesis of the Floating Harbor Syndrome: Case
Report of Long-Term Growth Hormone Treatment and a Literature Review
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Finally, we suggested a new model of FHS pathogenesis which provides
possible basis for the dominant negative nature of FHS-causing mutations
and explains limited effects of GH treatment in FHS.
explanation: This supports a dominant-negative SRCAP disease mechanism underlying Floating-Harbor syndrome.
downstream:
- target: Short stature
description: Developmental transcriptional dysregulation contributes to impaired linear growth.
- target: Delayed skeletal maturation
description: Developmental dysregulation contributes to delayed bone age.
- target: Abnormal facial shape
description: Developmental dysregulation contributes to a recognizable craniofacial phenotype.
- target: Brachydactyly
description: Developmental dysregulation contributes to characteristic skeletal anomalies.
- target: Intellectual disability
description: Disrupted chromatin-associated developmental regulation contributes to neurocognitive impairment.
- target: Delayed speech and language development
description: Neurodevelopmental dysregulation contributes to severe speech and language impairment.
- target: Hypernasal speech
description: Developmental dysregulation contributes to the characteristic hypernasal voice quality.
- target: High-pitched voice
description: Developmental dysregulation contributes to the characteristic high-pitched voice quality.
phenotypes:
- name: Short stature
category: Growth
diagnostic: true
description: Postnatal short stature is a defining clinical feature of Floating-Harbor syndrome.
phenotype_term:
preferred_term: Short stature
term:
id: HP:0004322
label: Short stature
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature;
explanation: This directly supports short stature as a core phenotype.
- name: Delayed speech and language development
category: Neurologic
diagnostic: true
description: Severe language impairment is one of the major developmental manifestations of Floating-Harbor syndrome.
phenotype_term:
preferred_term: Delayed speech and language development
term:
id: HP:0000750
label: Delayed speech and language development
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature; bone age delay that normalizes between
ages six and 12 years; skeletal anomalies (brachydactyly, broad
fingertips, clinodactyly, short thumbs, prominent joints, and clavicular
abnormalities); severe receptive and expressive language impairment;
explanation: This directly supports severe speech and language impairment as a core developmental feature.
- name: Delayed skeletal maturation
category: Growth
diagnostic: true
description: Delayed bone age is a classic diagnostic feature of Floating-Harbor syndrome.
phenotype_term:
preferred_term: Delayed skeletal maturation
term:
id: HP:0002750
label: Delayed skeletal maturation
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature; bone age delay that normalizes between
ages six and 12 years; skeletal anomalies (brachydactyly, broad
fingertips, clinodactyly, short thumbs, prominent joints, and clavicular
abnormalities); severe receptive and expressive language impairment;
explanation: This directly supports delayed skeletal maturation as a characteristic feature of Floating-Harbor syndrome.
- name: Abnormal facial shape
category: Morphological
diagnostic: true
description: Typical craniofacial features are a defining part of the Floating-Harbor syndrome phenotype.
phenotype_term:
preferred_term: Abnormal facial shape
term:
id: HP:0001999
label: Abnormal facial shape
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature;
explanation: This directly supports a characteristic abnormal facial shape in Floating-Harbor syndrome.
- name: Brachydactyly
category: Morphological
description: Brachydactyly is a representative skeletal anomaly in Floating-Harbor syndrome.
phenotype_term:
preferred_term: Brachydactyly
term:
id: HP:0001156
label: Brachydactyly
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature; bone age delay that normalizes between
ages six and 12 years; skeletal anomalies (brachydactyly, broad
fingertips, clinodactyly, short thumbs, prominent joints, and clavicular
abnormalities); severe receptive and expressive language impairment;
explanation: This directly supports brachydactyly as part of the skeletal phenotype in Floating-Harbor syndrome.
- name: Intellectual disability
category: Neurologic
description: Intellectual disability is usually mild to moderate in affected individuals.
phenotype_term:
preferred_term: Intellectual disability
term:
id: HP:0001249
label: Intellectual disability
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature; bone age delay that normalizes between
ages six and 12 years; skeletal anomalies (brachydactyly, broad
fingertips, clinodactyly, short thumbs, prominent joints, and clavicular
abnormalities); severe receptive and expressive language impairment;
hypernasality and high-pitched voice; and intellectual disability that is
typically mild to moderate.
explanation: This directly supports intellectual disability as a recurrent phenotype.
- name: Hypernasal speech
category: Otolaryngologic
description: Hypernasality is a characteristic voice and speech feature in Floating-Harbor syndrome.
phenotype_term:
preferred_term: Hypernasal speech
term:
id: HP:0001611
label: Hypernasal speech
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature; bone age delay that normalizes between
ages six and 12 years; skeletal anomalies (brachydactyly, broad
fingertips, clinodactyly, short thumbs, prominent joints, and clavicular
abnormalities); severe receptive and expressive language impairment;
hypernasality and high-pitched voice; and intellectual disability that is
typically mild to moderate.
explanation: This directly supports hypernasal speech as a characteristic voice phenotype in Floating-Harbor syndrome.
- name: High-pitched voice
category: Otolaryngologic
description: A high-pitched voice is a characteristic voice phenotype in Floating-Harbor syndrome.
phenotype_term:
preferred_term: High-pitched voice
term:
id: HP:0001620
label: Abnormally high-pitched voice
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
SRCAP-related Floating-Harbor syndrome (SRCAP-FHS) is characterized by
typical craniofacial features; low birth weight, normal head
circumference, and short stature; bone age delay that normalizes between
ages six and 12 years; skeletal anomalies (brachydactyly, broad
fingertips, clinodactyly, short thumbs, prominent joints, and clavicular
abnormalities); severe receptive and expressive language impairment;
hypernasality and high-pitched voice; and intellectual disability that is
typically mild to moderate.
explanation: This directly supports a high-pitched voice as a characteristic voice phenotype in Floating-Harbor syndrome.
biochemical: []
genetic:
- name: SRCAP
association: Causal heterozygous truncating variant
gene_term:
preferred_term: SRCAP
term:
id: hgnc:16974
label: SRCAP
notes: >-
Floating-Harbor syndrome is caused by heterozygous pathogenic SRCAP
variants, especially truncating variants in exons 33 and 34.
evidence:
- reference: DOI:10.3389/fgene.2022.846101
reference_title: >-
Molecular Genetics and Pathogenesis of the Floating Harbor Syndrome: Case
Report of Long-Term Growth Hormone Treatment and a Literature Review
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
FHS is caused by heterozygous mutations in the SRCAP gene; however,
little is known about the pathogenesis of FHS or the effectiveness of its
treatment.
explanation: This directly supports SRCAP as the causal gene for Floating-Harbor syndrome.
- reference: CGGV:assertion_5b414014-3a99-48f2-aac1-20903838af0f-2023-08-01T063000.000Z
reference_title: "SRCAP / Floating-Harbor syndrome (Definitive)"
supports: SUPPORT
evidence_source: OTHER
snippet: "SRCAP | HGNC:16974 | Floating-Harbor syndrome | MONDO:0007621 | AD | Definitive"
explanation: ClinGen classifies the SRCAP-Floating-Harbor syndrome gene-disease relationship as definitive with autosomal dominant inheritance.
environmental: []
treatments:
- name: Growth hormone therapy
description: >-
Recombinant human growth hormone has been used for short stature, but
published evidence suggests only limited benefit in Floating-Harbor
syndrome.
treatment_term:
preferred_term: human growth hormone replacement therapy
term:
id: MAXO:0000780
label: human growth hormone replacement therapy
target_phenotypes:
- preferred_term: Short stature
term:
id: HP:0004322
label: Short stature
evidence:
- reference: DOI:10.3389/fgene.2022.846101
reference_title: >-
Molecular Genetics and Pathogenesis of the Floating Harbor Syndrome: Case
Report of Long-Term Growth Hormone Treatment and a Literature Review
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We report the history of treatment of the proband with GH, which resulted
in modest improvement in growth prior to puberty.
explanation: This supports growth hormone therapy as a used but only modestly effective treatment for short stature.
- name: Developmental supportive care
description: Early intervention, special education, and related supportive services are recommended for developmental disability management.
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
target_phenotypes:
- preferred_term: Delayed speech and language development
term:
id: HP:0000750
label: Delayed speech and language development
- preferred_term: Intellectual disability
term:
id: HP:0001249
label: Intellectual disability
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Early intervention programs, special education, and vocational training to address developmental disabilities; communication rehabilitation with sign language or alternative means of communication; behavior management by a behavioral specialist / psychologist with consideration of medication as needed.
explanation: This directly supports developmental supportive care interventions in Floating-Harbor syndrome.
- name: Speech and communication therapy
description: Communication rehabilitation is recommended for the severe expressive and receptive language phenotype.
treatment_term:
preferred_term: speech therapy
term:
id: MAXO:0000930
label: speech therapy
target_phenotypes:
- preferred_term: Delayed speech and language development
term:
id: HP:0000750
label: Delayed speech and language development
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Early intervention programs, special education, and vocational training to address developmental disabilities; communication rehabilitation with sign language or alternative means of communication; behavior management by a behavioral specialist / psychologist with consideration of medication as needed.
explanation: This directly supports communication-focused rehabilitation for language impairment in Floating-Harbor syndrome.
diagnosis:
- name: SRCAP molecular genetic testing
description: Molecular genetic testing for a heterozygous pathogenic SRCAP variant confirms the diagnosis.
presence: Identification of a heterozygous pathogenic SRCAP variant establishes the diagnosis.
diagnosis_term:
preferred_term: molecular genetic testing
term:
id: MAXO:0000533
label: molecular genetic testing
qualifiers:
- predicate:
preferred_term: has participant
term:
id: RO:0000057
label: has participant
value:
preferred_term: SRCAP
term:
id: hgnc:16974
label: SRCAP
evidence:
- reference: PMID:23193612
reference_title: SRCAP-Related Floating-Harbor Syndrome.
supports: SUPPORT
evidence_source: OTHER
snippet: >-
DIAGNOSIS/TESTING: The diagnosis is established in a proband with
suggestive findings and a heterozygous SRCAP pathogenic variant
identified by molecular genetic testing.
explanation: This directly supports molecular genetic testing as the confirmatory diagnostic procedure.
differential_diagnoses: []
clinical_trials: []
datasets: []
notes: >-
Asta deep research was completed for this disorder. Final curation combined
the disease-specific pathogenesis review with GeneReviews for syndrome
definition, diagnosis, and inheritance.
references:
- reference: PMID:23193612
title: "SRCAP-Related Floating-Harbor Syndrome."
tags:
- GeneReviews
findings: []
This report is retrieval-only and is generated directly from Asta results.
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