Coffin-Lowry syndrome is an X-linked neurodevelopmental disorder caused by pathogenic variants in RPS6KA3, which encodes the serine-threonine kinase RSK2. Loss of RSK2 function perturbs downstream ERK signaling and activity-dependent transcriptional regulation in neural and skeletal tissues. The syndrome is characterized by developmental delay or intellectual disability, distinctive facial appearance, progressive skeletal abnormalities, stimulus-induced drop episodes, seizures in a subset of patients, and other systemic complications.
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Conditions with similar clinical presentations that must be differentiated from Coffin-Lowry syndrome:
name: Coffin-Lowry syndrome
creation_date: '2026-04-11T19:38:25Z'
updated_date: '2026-04-12T00:02:00Z'
category: Mendelian
description: >-
Coffin-Lowry syndrome is an X-linked neurodevelopmental disorder caused by
pathogenic variants in RPS6KA3, which encodes the serine-threonine kinase
RSK2. Loss of RSK2 function perturbs downstream ERK signaling and
activity-dependent transcriptional regulation in neural and skeletal tissues.
The syndrome is characterized by developmental delay or intellectual
disability, distinctive facial appearance, progressive skeletal abnormalities,
stimulus-induced drop episodes, seizures in a subset of patients, and other
systemic complications.
disease_term:
preferred_term: Coffin-Lowry syndrome
term:
id: MONDO:0010561
label: Coffin-Lowry syndrome
mappings:
mondo_mappings:
- term:
id: MONDO:0010561
label: Coffin-Lowry syndrome
mapping_predicate: skos:exactMatch
mapping_source: MONDO
parents:
- syndromic intellectual disability
- hereditary disease
inheritance:
- name: X-linked dominant inheritance
inheritance_term:
preferred_term: X-linked dominant inheritance
term:
id: HP:0001423
label: X-linked dominant inheritance
description: >-
Coffin-Lowry syndrome is a rare X-linked disorder caused by pathogenic
variants in RPS6KA3.
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Coffin-Lowry syndrome (CLS) is a rare X-linked disorder caused by pathogenic variants in RPS6KA3, presenting with intellectual disability, distinctive facial and skeletal features, and variable systemic involvement.
explanation: >-
The systematic review directly supports X-linked inheritance and the core
causal gene.
pathophysiology:
- name: RPS6KA3 / RSK2 loss of function
description: >-
Coffin-Lowry syndrome is driven by loss of function of the X-linked kinase
RSK2 encoded by RPS6KA3.
genes:
- preferred_term: RPS6KA3
term:
id: hgnc:10432
label: RPS6KA3
evidence:
- reference: PMID:23389038
reference_title: "Rsk2 Knockdown in PC12 Cells Results in Sp1 Dependent Increased Expression of the Gria2 Gene, Encoding the AMPA Receptor Subunit GluR2."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Highly heterogeneous loss-of-function mutations affecting this gene are responsible for a severe syndromic form of cognitive impairment, Coffin-Lowry syndrome.
explanation: >-
This directly identifies RSK2 loss of function as the causal mechanism.
downstream:
- target: Abnormal ERK-RSK2-Sp1 transcriptional signaling
description: Loss of RSK2 dysregulates downstream ERK-dependent transcriptional control
- name: Abnormal ERK-RSK2-Sp1 transcriptional signaling
description: >-
RSK2 normally modulates ERK output. RSK2 deficiency leads to abnormally
increased ERK1/2 activity with altered transcriptional control in neural
cells.
biological_processes:
- preferred_term: MAPK cascade
modifier: ABNORMAL
term:
id: GO:0000165
label: MAPK cascade
evidence:
- reference: PMID:23389038
reference_title: "Rsk2 Knockdown in PC12 Cells Results in Sp1 Dependent Increased Expression of the Gria2 Gene, Encoding the AMPA Receptor Subunit GluR2."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
We show that Rsk2 silencing leads also to an elevation of ERK1/2 phosphorylation as well as of GluR2 expression and that the increased level of GluR2 expression results from the increased ERK1/2 activity on the transcription factor Sp1.
explanation: >-
This cell-model study directly supports abnormal ERK-dependent
transcriptional signaling downstream of RSK2 deficiency.
downstream:
- target: AMPA receptor GluR2 upregulation
description: Dysregulated ERK-Sp1 signaling increases downstream neuronal gene expression programs
- target: Progressive skeletal abnormalities
description: Abnormal downstream signaling also perturbs musculoskeletal development
- name: AMPA receptor GluR2 upregulation
description: >-
RSK2 deficiency increases ERK-Sp1-dependent expression of the AMPA receptor
subunit GluR2 in neuronal cells.
biological_processes:
- preferred_term: regulation of transmembrane transport
modifier: ABNORMAL
term:
id: GO:0034762
label: regulation of transmembrane transport
evidence:
- reference: PMID:23389038
reference_title: "Rsk2 Knockdown in PC12 Cells Results in Sp1 Dependent Increased Expression of the Gria2 Gene, Encoding the AMPA Receptor Subunit GluR2."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
We show that Rsk2 silencing leads also to an elevation of ERK1/2 phosphorylation as well as of GluR2 expression and that the increased level of GluR2 expression results from the increased ERK1/2 activity on the transcription factor Sp1.
explanation: >-
This is the primary mechanistic finding of the PC12-cell study and defines
a discrete downstream neuronal signaling abnormality.
downstream:
- target: Neurodevelopmental dysfunction
description: Altered neuronal signaling contributes to impaired cognitive and developmental trajectories
- target: Seizure susceptibility and stimulus-induced drop episodes
description: Altered neuronal excitability contributes to paroxysmal neurologic manifestations
- name: Neurodevelopmental dysfunction
description: >-
Downstream effects of RSK2 deficiency disrupt neurodevelopment, producing
developmental delay and intellectual disability.
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This systematic review highlights recurrent neurodevelopmental, neurologic, and skeletal phenotypes in CLS and delineates mutation-specific risks, particularly for SIDEs and seizures.
explanation: >-
The disease-focused review supports neurodevelopmental dysfunction as a
distinct downstream consequence of RSK2 deficiency.
- name: Seizure susceptibility and stimulus-induced drop episodes
description: >-
The neurologic phenotype includes recurrent seizures and stimulus-induced drop
episodes in a clinically important subset of affected individuals.
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Developmental delay (87.5%) and intellectual disability (66.7%) were the most frequent features, alongside musculoskeletal deformities (kyphoscoliosis 33.3%, pectus anomalies 19.4%) and neurologic involvement (SIDEs 12.5%, seizures 15.3%, spasticity 5.6%).
explanation: >-
This directly supports a distinct downstream neurologic branch involving
SIDEs and seizures.
- name: Progressive skeletal abnormalities
description: >-
Downstream effects of RSK2 deficiency perturb skeletal development and are
associated with progressive musculoskeletal deformity.
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This systematic review highlights recurrent neurodevelopmental, neurologic, and skeletal phenotypes in CLS and delineates mutation-specific risks, particularly for SIDEs and seizures.
explanation: >-
This supports skeletal abnormality as a separate downstream disease domain.
phenotypes:
- name: Developmental delay
category: Neurologic
description: >-
Developmental delay is one of the most frequent manifestations of
Coffin-Lowry syndrome.
phenotype_term:
preferred_term: Global developmental delay
term:
id: HP:0001263
label: Global developmental delay
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Developmental delay (87.5%) and intellectual disability (66.7%) were the most frequent features, alongside musculoskeletal deformities (kyphoscoliosis 33.3%, pectus anomalies 19.4%) and neurologic involvement (SIDEs 12.5%, seizures 15.3%, spasticity 5.6%).
explanation: >-
This directly quantifies developmental delay as the most common feature in
the curated cohort.
- name: Intellectual disability
category: Neurologic
description: >-
Intellectual disability is a central neurodevelopmental manifestation of
Coffin-Lowry syndrome.
phenotype_term:
preferred_term: Intellectual disability
term:
id: HP:0001249
label: Intellectual disability
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Developmental delay (87.5%) and intellectual disability (66.7%) were the most frequent features, alongside musculoskeletal deformities (kyphoscoliosis 33.3%, pectus anomalies 19.4%) and neurologic involvement (SIDEs 12.5%, seizures 15.3%, spasticity 5.6%).
explanation: >-
The systematic review explicitly reports intellectual disability as a
frequent core feature.
- name: Kyphoscoliosis
category: Skeletal
description: >-
Progressive kyphoscoliosis is one of the recurring skeletal deformities in
Coffin-Lowry syndrome.
phenotype_term:
preferred_term: Kyphoscoliosis
term:
id: HP:0002751
label: Kyphoscoliosis
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Developmental delay (87.5%) and intellectual disability (66.7%) were the most frequent features, alongside musculoskeletal deformities (kyphoscoliosis 33.3%, pectus anomalies 19.4%) and neurologic involvement (SIDEs 12.5%, seizures 15.3%, spasticity 5.6%).
explanation: >-
This directly supports kyphoscoliosis as a common musculoskeletal
deformity in the syndrome.
- name: Seizure
category: Neurologic
description: >-
Seizures occur in a subset of affected individuals and are part of the
neurologic phenotype.
phenotype_term:
preferred_term: Seizure
term:
id: HP:0001250
label: Seizure
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Developmental delay (87.5%) and intellectual disability (66.7%) were the most frequent features, alongside musculoskeletal deformities (kyphoscoliosis 33.3%, pectus anomalies 19.4%) and neurologic involvement (SIDEs 12.5%, seizures 15.3%, spasticity 5.6%).
explanation: >-
The review directly identifies seizures in the disease cohort.
- name: Stimulus-induced drop episodes
category: Neurologic
description: >-
Stimulus-induced drop episodes are a hallmark paroxysmal neurologic feature
of Coffin-Lowry syndrome.
phenotype_term:
preferred_term: Stimulus-induced drop episodes
term:
id: HP:0010819
label: Atonic seizure
notes: >-
HP:0010819 is used as the closest available HPO approximation for the
syndrome's characteristic stimulus-induced drop episodes.
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Developmental delay (87.5%) and intellectual disability (66.7%) were the most frequent features, alongside musculoskeletal deformities (kyphoscoliosis 33.3%, pectus anomalies 19.4%) and neurologic involvement (SIDEs 12.5%, seizures 15.3%, spasticity 5.6%).
explanation: >-
This directly supports SIDEs as a recognizable, syndrome-defining
neurologic feature.
- name: Abnormal facial shape
category: Craniofacial
description: >-
Distinctive facial dysmorphism is part of the canonical Coffin-Lowry
phenotype.
phenotype_term:
preferred_term: Abnormal facial shape
term:
id: HP:0001999
label: Abnormal facial shape
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Coffin-Lowry syndrome (CLS) is a rare X-linked disorder caused by pathogenic variants in RPS6KA3, presenting with intellectual disability, distinctive facial and skeletal features, and variable systemic involvement.
explanation: >-
The abstract explicitly identifies distinctive facial features as part of
the syndrome.
genetic:
- name: RPS6KA3
association: Loss-of-function
gene_term:
preferred_term: RPS6KA3
term:
id: hgnc:10432
label: RPS6KA3
notes: >-
Pathogenic RPS6KA3 variants abolish or attenuate RSK2 kinase function and
underlie the X-linked Coffin-Lowry phenotype.
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Coffin-Lowry syndrome (CLS) is a rare X-linked disorder caused by pathogenic variants in RPS6KA3, presenting with intellectual disability, distinctive facial and skeletal features, and variable systemic involvement.
explanation: >-
This directly identifies RPS6KA3 as the causal disease gene.
- reference: CGGV:assertion_af32a931-1d55-432f-82cf-ce87f6c26580-2019-05-28T040000.000Z
reference_title: "RPS6KA3 / Coffin-Lowry syndrome (Definitive)"
supports: SUPPORT
evidence_source: OTHER
snippet: "RPS6KA3 | HGNC:10432 | Coffin-Lowry syndrome | MONDO:0010561 | XL | Definitive"
explanation: ClinGen classifies the RPS6KA3-Coffin-Lowry syndrome gene-disease relationship as definitive with X-linked inheritance.
treatments:
- name: Supportive multidisciplinary care
description: >-
Current management is supportive and includes developmental therapies,
orthopedic monitoring, seizure management, and surveillance for cardiac and
neurologic complications.
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
differential_diagnoses:
- name: Kabuki syndrome
disease_term:
preferred_term: Kabuki syndrome
term:
id: MONDO:0016512
label: Kabuki syndrome
description: >-
Kabuki syndrome overlaps with Coffin-Lowry syndrome through developmental
delay, craniofacial dysmorphism, and skeletal abnormalities, but it follows
a different Mendelian mechanism and lacks the classic RPS6KA3-associated
stimulus-induced drop episode phenotype.
distinguishing_features:
- X-linked inheritance and stimulus-induced drop episodes favor Coffin-Lowry syndrome.
- Persistent fingertip pads and the typical Kabuki facial gestalt favor Kabuki syndrome.
- name: Noonan syndrome
disease_term:
preferred_term: Noonan syndrome
term:
id: MONDO:0018997
label: Noonan syndrome
description: >-
Noonan syndrome can overlap through short stature, developmental issues, and
chest or spinal abnormalities, but it is usually distinguished by
RASopathy-associated cardiac and lymphatic findings rather than the classic
Coffin-Lowry neurocognitive-skeletal pattern.
distinguishing_features:
- Severe intellectual disability with progressive skeletal deformity favors Coffin-Lowry syndrome.
- Pulmonary valve stenosis and typical RASopathy facies favor Noonan syndrome.
clinical_trials: []
datasets:
- accession: PMID:41589305
title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
description: >-
Human clinical-genetic dataset synthesizing 72 molecularly confirmed
Coffin-Lowry syndrome cases with standardized phenotypic frequencies and
genotype-phenotype associations.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
sample_count: 72
conditions:
- Coffin-Lowry syndrome
- RPS6KA3-confirmed cases
publication: PMID:41589305
evidence:
- reference: PMID:41589305
reference_title: "Coffin-Lowry syndrome: a systematic review of RPS6KA3 confirmed cases and implications for diagnosis and counseling."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
METHODS: We conducted a systematic review of published cases (n = 72) following PRISMA guidelines.
explanation: >-
This defines a curated disease-specific cohort dataset that can support
downstream phenotype and genotype analyses.
notes: >-
Asta deep research was run as requested, but curation relied on directly
reviewed PubMed references for the final evidence blocks.
This report is retrieval-only and is generated directly from Asta results.
search_papers_by_relevance with snippet_search.