Kilquist syndrome is an ultra-rare autosomal recessive multisystem disorder caused by biallelic loss-of-function variants in SLC12A2, which encodes the NKCC1 sodium-potassium-chloride cotransporter. This entry is scoped to the biallelic Kilquist syndrome phenotype rather than the broader dominant SLC12A2-related cochleovestibular/neurodevelopmental spectrum. Loss of NKCC1 disrupts ion transport in the cochlea, neurons, and secretory epithelia, producing profound sensorineural hearing loss, severe developmental delay, hypotonia, growth failure, gastrointestinal abnormalities, and marked impairment of saliva, tears, sweat, and respiratory mucus handling.
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Conditions with similar clinical presentations that must be differentiated from Kilquist syndrome:
name: Kilquist syndrome
creation_date: '2026-04-11T19:38:25Z'
updated_date: '2026-05-31T11:05:00Z'
category: Mendelian
description: >-
Kilquist syndrome is an ultra-rare autosomal recessive multisystem disorder
caused by biallelic loss-of-function variants in SLC12A2, which encodes the
NKCC1 sodium-potassium-chloride cotransporter. This entry is scoped to the
biallelic Kilquist syndrome phenotype rather than the broader dominant
SLC12A2-related cochleovestibular/neurodevelopmental spectrum. Loss of NKCC1
disrupts ion transport in the cochlea, neurons, and secretory epithelia,
producing profound sensorineural hearing loss, severe developmental delay,
hypotonia, growth failure, gastrointestinal abnormalities, and marked
impairment of saliva, tears, sweat, and respiratory mucus handling.
disease_term:
preferred_term: Kilquist syndrome
term:
id: MONDO:0033664
label: Kilquist syndrome
mappings:
mondo_mappings:
- term:
id: MONDO:0033664
label: Kilquist syndrome
mapping_predicate: skos:exactMatch
mapping_source: MONDO
parents:
- hereditary disease
- syndromic hearing loss
inheritance:
- name: Autosomal recessive inheritance
inheritance_term:
preferred_term: Autosomal recessive inheritance
term:
id: HP:0000007
label: Autosomal recessive inheritance
description: >-
Kilquist syndrome is caused by biallelic loss of function of SLC12A2.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Like other SLC12 gene family disorders, Kilquist syndrome is an autosomal recessive condition caused by the loss of function of SLC12A2.
explanation: >-
This directly states the mode of inheritance and causal mechanism.
pathophysiology:
- name: Biallelic SLC12A2 / NKCC1 deficiency
description: >-
Kilquist syndrome is caused by biallelic pathogenic variants in SLC12A2,
which encodes the NKCC1 cotransporter.
genes:
- preferred_term: SLC12A2
term:
id: hgnc:10911
label: SLC12A2
biological_processes:
- preferred_term: monoatomic ion transmembrane transport
modifier: ABNORMAL
term:
id: GO:0034220
label: monoatomic ion transmembrane transport
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Next-generation sequencing revealed a uniparental isodisomy in chromosome 5, and a 22 kb homozygous deletion in SLC12A2, which encodes for sodium, potassium, and chloride transporter in the basolateral membrane of secretory epithelia.
explanation: >-
This directly anchors the syndrome to a biallelic SLC12A2 lesion affecting
the NKCC1 transporter.
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Together with the described phenotype of the Slc12a2-knockout mouse model, our results suggest that the absence of functional SLC12A2 causes a new genetic syndrome and is crucial for the development of auditory, neurologic, and gastrointestinal tissues.
explanation: >-
This integrates the human proband with model-organism context; tissue-level
inferences below are separated into human, model, and in vitro evidence.
downstream:
- target: Truncated or absent NKCC1 protein
description: Biallelic pathogenic variants abolish normal NKCC1 protein production or stability
- name: Truncated or absent NKCC1 protein
description: >-
Pathogenic splice variants produce truncated NKCC1 and impair dimerization or
eliminate detectable transporter protein.
genes:
- preferred_term: SLC12A2
term:
id: hgnc:10911
label: SLC12A2
evidence:
- reference: PMID:40678848
reference_title: "Identification and Characterization of a Novel Biallelic SLC12A2 Variant Associated With Kilquist Syndrome (OMIM #619080)."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
The effect of this mutation was further investigated using exon-walking PCR and Sanger sequencing, which confirmed exon 23 skipping in the patient's mRNA, resulting in a truncated NKCC1 protein.
explanation: >-
This directly supports RNA-level and protein-level disruption of NKCC1.
- reference: PMID:40678848
reference_title: "Identification and Characterization of a Novel Biallelic SLC12A2 Variant Associated With Kilquist Syndrome (OMIM #619080)."
supports: SUPPORT
evidence_source: COMPUTATIONAL
snippet: In silico structural modeling suggested compromised dimerization stability
explanation: >-
This supports a computationally inferred structural mechanism in which
mutant NKCC1 has impaired dimerization stability.
- reference: PMID:40678848
reference_title: "Identification and Characterization of a Novel Biallelic SLC12A2 Variant Associated With Kilquist Syndrome (OMIM #619080)."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
immunoblotting analysis, revealing the absence of the dimeric form of NKCC1 in patient-derived peripheral blood mononuclear cells.
explanation: >-
This provides cell-based support that the mutant transporter fails to form
the normal dimeric state.
downstream:
- target: Cochlear endolymph secretion failure
description: Loss of NKCC1 disrupts the inner-ear ion transport needed for hearing
- target: Neuronal ion-homeostasis disruption
description: Loss of NKCC1 perturbs neuronal chloride handling and early brain development
- target: Secretory epithelial fluid-secretion failure
description: Loss of NKCC1 compromises epithelial fluid secretion
- name: Cochlear endolymph secretion failure
description: >-
NKCC1 deficiency disrupts the inner-ear fluid-secretion program required for
normal auditory function and underlies profound hearing loss.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
The hallmark feature of the NKCC1 knockout mouse is a “shaker/waltzer”
phenotype characteristic of inner ear dysfunction, histologically seen as a
complete collapse of the cochlear duct
explanation: >-
The cochlear endolymph branch is primarily supported by mouse knockout
inner-ear pathology, with human profound hearing loss as the clinical
correlate.
downstream:
- target: Profound sensorineural hearing impairment
description: Cochlear fluid-homeostasis failure produces the syndrome's hallmark deafness
- name: Neuronal ion-homeostasis disruption
description: >-
NKCC1 deficiency perturbs neuronal chloride transport and brain-development
programs, contributing to severe developmental impairment and hypotonia.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: PARTIAL
evidence_source: MODEL_ORGANISM
snippet: >-
In the mouse model, NKCC1 is necessary for maintaining normal neuronal
migration, and is implicated in dendritic growth and increasing neuron
density through its regulation of GABAergic signaling
explanation: >-
This mechanistic neuronal-development branch is model-supported and
plausibly explains human developmental delay, but is not directly assayed
in human neural tissue.
downstream:
- target: Severe neurodevelopmental impairment
description: Neuronal transport defects contribute to developmental delay and hypotonia
- name: Secretory epithelial fluid-secretion failure
description: >-
Loss of NKCC1 compromises secretory epithelial function, producing marked
salivary and other exocrine secretion defects with gastrointestinal and
respiratory consequences.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Our case is the first known human presentation of complete loss of NKCC1 and demonstrates the role of SLC12A2 in human secretory systems and disease.
explanation: >-
This directly supports a secretory-epithelial branch downstream of NKCC1
loss.
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
NKCC1 knockout mice show a significant reduction in saliva production due
to the inability of the parotid gland to conserve NaCl
explanation: >-
Provides model-organism support for salivary epithelial secretion failure.
downstream:
- target: Xerostomia and epithelial secretion defects
description: Secretory failure causes absent salivation and related epithelial symptoms
- target: Gastrointestinal and respiratory complications
description: Secretory failure contributes to severe GI dysfunction and mucus-related respiratory problems
- name: Profound sensorineural hearing impairment
description: >-
Inner-ear dysfunction produces the hallmark profound bilateral sensorineural
hearing loss of Kilquist syndrome.
evidence:
- reference: PMID:40678848
reference_title: "Identification and Characterization of a Novel Biallelic SLC12A2 Variant Associated With Kilquist Syndrome (OMIM #619080)."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This study presents the case of a child with multiple congenital anomalies, severe hypotonia, and profound bilateral sensorineural hearing loss.
explanation: >-
This supports the phenotype-level auditory outcome downstream of cochlear
NKCC1 dysfunction.
- name: Severe neurodevelopmental impairment
description: >-
Neuronal NKCC1 dysfunction contributes to global developmental delay and
hypotonia.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Herein we describe a child admitted to the NIH Undiagnosed Diseases Program with global developmental delay, sensorineural hearing loss, gastrointestinal abnormalities, and absent salivation.
explanation: >-
This directly supports severe neurodevelopmental impairment as a downstream
outcome in the human syndrome.
- name: Xerostomia and epithelial secretion defects
description: >-
Secretory failure produces profound impairment of salivary and other
epithelial secretions.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This new syndrome is associated with a loss of function mutation in SLC12A2; we now refer to this novel disease as Kilquist syndrome, which is additionally characterized by the absence of saliva, tears, and sweat, mucus plugging and respiratory problems reminiscent of cystic fibrosis, and severe gastrointestinal problems.
explanation: >-
This directly supports epithelial secretion failure as a distinct
downstream branch of disease.
- name: Gastrointestinal and respiratory complications
description: >-
NKCC1-related secretory dysfunction contributes to severe gastrointestinal
abnormalities and mucus-related respiratory disease.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In summary, we present a novel cause of syndromic hearing loss associated with global developmental delay, failure to thrive, respiratory problems, absent salivation and sweat production, and gastrointestinal abnormalities.
explanation: >-
This directly supports downstream gastrointestinal and respiratory
complications in the human syndrome.
phenotypes:
- name: Sensorineural hearing impairment
category: Otolaryngologic
description: >-
Profound bilateral sensorineural hearing loss is the hallmark phenotype of
Kilquist syndrome.
phenotype_term:
preferred_term: Sensorineural hearing impairment
term:
id: HP:0000407
label: Sensorineural hearing impairment
evidence:
- reference: PMID:40678848
reference_title: "Identification and Characterization of a Novel Biallelic SLC12A2 Variant Associated With Kilquist Syndrome (OMIM #619080)."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This study presents the case of a child with multiple congenital anomalies, severe hypotonia, and profound bilateral sensorineural hearing loss.
explanation: >-
This directly supports profound sensorineural hearing loss as a core
phenotype.
- name: Global developmental delay
category: Neurologic
description: >-
Severe developmental impairment is part of the syndromic neurologic
phenotype.
phenotype_term:
preferred_term: Global developmental delay
term:
id: HP:0001263
label: Global developmental delay
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Herein we describe a child admitted to the NIH Undiagnosed Diseases Program with global developmental delay, sensorineural hearing loss, gastrointestinal abnormalities, and absent salivation.
explanation: >-
The original syndrome description directly identifies global developmental
delay.
- name: Hypotonia
category: Neurologic
description: >-
Generalized hypotonia is a recurrent neurologic feature in Kilquist
syndrome.
phenotype_term:
preferred_term: Hypotonia
term:
id: HP:0001252
label: Hypotonia
evidence:
- reference: PMID:40678848
reference_title: "Identification and Characterization of a Novel Biallelic SLC12A2 Variant Associated With Kilquist Syndrome (OMIM #619080)."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This study presents the case of a child with multiple congenital anomalies, severe hypotonia, and profound bilateral sensorineural hearing loss.
explanation: >-
This directly supports hypotonia as part of the phenotype.
- name: Failure to thrive
category: Growth
description: >-
Poor growth and nutritional failure reflect the syndrome's severe
gastrointestinal and secretory dysfunction.
phenotype_term:
preferred_term: Failure to thrive
term:
id: HP:0001508
label: Failure to thrive
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In summary, we present a novel cause of syndromic hearing loss associated with global developmental delay, failure to thrive, respiratory problems, absent salivation and sweat production, and gastrointestinal abnormalities.
explanation: >-
The syndrome summary explicitly includes failure to thrive.
- name: Xerostomia
category: Gastrointestinal
description: >-
Absent or severely reduced salivation is a hallmark secretory manifestation
of Kilquist syndrome.
phenotype_term:
preferred_term: Xerostomia
term:
id: HP:0000217
label: Xerostomia
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This new syndrome is associated with a loss of function mutation in SLC12A2; we now refer to this novel disease as Kilquist syndrome, which is additionally characterized by the absence of saliva, tears, and sweat, mucus plugging and respiratory problems reminiscent of cystic fibrosis, and severe gastrointestinal problems.
explanation: >-
This directly supports severe salivary deficiency as a core phenotype.
- name: Absent tear production with dry eye risk
category: Ophthalmologic
description: >-
Absence of tear production reflects the same exocrine secretory failure that
causes absent salivation and sweat production.
phenotype_term:
preferred_term: Absent tear production
term:
id: HP:0001097
label: Keratoconjunctivitis sicca
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Schirmer test confirmed absence of tears (<1mm bilaterally).
explanation: >-
Directly documents absent lacrimation; the linked HPO term captures the
resulting tear-film deficiency/dry-eye phenotype.
- name: Anhidrosis
category: Dermatologic
description: >-
Absent or markedly impaired sweat production is part of the multisystem
secretory epithelial phenotype.
phenotype_term:
preferred_term: Anhidrosis
term:
id: HP:0000970
label: Anhidrosis
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
No sympathetic postganglionic cholinergic function was observed in either
the forearm or ankle by QSWEAT test, demonstrating sympathetic
postganglionic sweat dysfunction
explanation: >-
Supports sweat-production failure as a documented Kilquist syndrome
phenotype.
- name: Mucus plugging with respiratory problems
category: Respiratory
description: >-
Secretory epithelial dysfunction can produce mucus plugging and respiratory
problems reminiscent of cystic fibrosis.
phenotype_term:
preferred_term: Mucus plugging with airway obstruction
term:
id: HP:0006536
label: Airway obstruction
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
mucus plugging and respiratory problems reminiscent of cystic fibrosis
explanation: >-
Supports mucus-related respiratory disease as a human clinical phenotype.
- name: Gastrointestinal dysmotility and malrotation
category: Gastrointestinal
description: >-
Severe gastrointestinal involvement includes malrotation, reflux,
constipation, and broader dysmotility or secretion-related complications.
phenotype_term:
preferred_term: Gastrointestinal dysmotility
term:
id: HP:0002579
label: Gastrointestinal dysmotility
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Our patient has a history of significant gastrointestinal problems
including malrotation, constipation, and concern for blood in the GI tract
based on periodic coffee-ground G-tube aspirations.
explanation: >-
Supports severe gastrointestinal involvement with dysmotility-compatible
features in the foundational patient.
genetic:
- name: SLC12A2
association: Loss-of-function
gene_term:
preferred_term: SLC12A2
term:
id: hgnc:10911
label: SLC12A2
notes: >-
Kilquist syndrome is caused by biallelic loss of NKCC1 function due to
deletion or splice-disrupting variants in SLC12A2.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Like other SLC12 gene family disorders, Kilquist syndrome is an autosomal recessive condition caused by the loss of function of SLC12A2.
explanation: >-
This directly supports the causal gene and variant mechanism.
diagnosis:
- name: Deletion-sensitive SLC12A2 molecular genetic testing
diagnosis_term:
preferred_term: molecular genetic testing
term:
id: MAXO:0000533
label: molecular genetic testing
description: >-
Diagnosis is established by identifying biallelic pathogenic SLC12A2
variants. Because reported biallelic disease includes both a homozygous
deletion and a homozygous splice variant, testing should include sequencing
plus deletion/duplication- or genome/CNV-sensitive methods.
results: >-
Biallelic loss-of-function SLC12A2 variants support the Kilquist syndrome
diagnosis; isolated heterozygous variants should be interpreted in the
separate dominant SLC12A2-related spectrum.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Whole genome-sequencing identified a homozygous deletion of 22kb in SLC12A2.
explanation: >-
The foundational case demonstrates a deletion-sensitive molecular
diagnosis of biallelic SLC12A2 loss.
- reference: PMID:40678848
reference_title: "Identification and Characterization of a Novel Biallelic SLC12A2 Variant Associated With Kilquist Syndrome (OMIM #619080)."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
genetic investigations confirmed the diagnosis by identifying a novel homozygous splice-site variant
explanation: >-
The second molecularly confirmed report supports sequence-level testing
for biallelic SLC12A2 splice variants.
- name: Audiology evaluation with ABR and otoacoustic emissions
diagnosis_term:
preferred_term: hearing examination
term:
id: MAXO:0000873
label: hearing examination
description: >-
Early audiology evaluation should document the severity and type of hearing
loss using electrophysiologic testing, including auditory brainstem response
and otoacoustic emissions when clinically available.
results: >-
Profound bilateral sensorineural hearing loss with absent otoacoustic
emissions supports the auditory component of the Kilquist syndrome
phenotype.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Auditory- brainstem evoked potentials (ABR) demonstrated profound bilateral sensorineural hearing loss, Distortion Product Otoacoustic Emissions (DPOAE) were absent bilaterally, and he was fitted with hearing aids.
explanation: >-
The report documents ABR and DPOAE findings used to characterize the
profound sensorineural hearing phenotype.
- name: Neurodevelopmental assessment
diagnosis_term:
preferred_term: neurodevelopmental assessment
term:
id: MAXO:0035041
label: neurodevelopmental assessment
description: >-
Formal developmental evaluation helps characterize the severe neurologic
involvement, establish support needs, and distinguish biallelic Kilquist
syndrome from cochlea-restricted dominant SLC12A2 presentations.
results: >-
Profound global delays across developmental domains support severe
neurodevelopmental involvement.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Neuropsychological testing demonstrated profound delays in all developmental areas, with skills ranging from 1 to 6 months.
explanation: >-
This supports neurodevelopmental testing as a key component of the
phenotypic assessment.
- name: Nutrition and gastrointestinal assessment
diagnosis_term:
preferred_term: nutrition assessment
term:
id: MAXO:0000624
label: nutrition assessment
description: >-
Growth, feeding, reflux, malrotation, constipation, and gastrostomy-tube
complications should be assessed because severe nutritional and
gastrointestinal problems are part of the reported biallelic syndrome.
results: >-
Failure to thrive, malnutrition, reflux, malrotation, constipation, or
gastrostomy dependence identify major supportive-care needs.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
While his calorie, protein, and water intake exceed his estimated needs (>95% of required daily allowance), he was severely malnourished.
explanation: >-
The original case supports nutrition assessment because severe
malnutrition occurred despite apparently adequate intake.
- name: Secretory epithelial assessment
diagnosis_term:
preferred_term: ophthalmic diagnostic procedure
term:
id: MAXO:0000967
label: ophthalmic diagnostic procedure
description: >-
Schirmer testing, oral/salivary evaluation, sweat-function assessment, and
review of mucus-related respiratory problems help document the
secretory-epithelial arm of the syndrome.
results: >-
Absent tears, severe oral dryness, absent salivary production, sweat
dysfunction, or mucus plugging support multisystem secretory failure.
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
An ophthalmologic exam was normal, although a Schirmer test confirmed absence of tears (<1mm bilaterally).
explanation: >-
The cited diagnostic procedure directly documented absent tear production.
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
There was severe oral dryness and saliva was not able to be produced by massage of the salivary glands.
explanation: >-
This supports targeted salivary assessment as part of documenting
secretory epithelial failure.
treatments:
- name: Supportive multidisciplinary management
description: >-
Management remains supportive and should be multidisciplinary because the
reported biallelic cases involve profound hearing loss, severe developmental
impairment, growth failure, gastrointestinal abnormalities, and secretory
epithelial complications.
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
In summary, we present a novel cause of syndromic hearing loss associated with global developmental delay, failure to thrive, respiratory problems, absent salivation and sweat production, and gastrointestinal abnormalities.
explanation: >-
This multisystem case summary supports multidisciplinary supportive
management, while not providing interventional efficacy data.
- name: Hearing rehabilitation and cochlear implantation
description: >-
Hearing-directed management may include hearing aids, cochlear implant
evaluation, and ongoing audiology support, but published experience is
limited and benefit may be incomplete.
treatment_term:
preferred_term: cochlear device implantation
term:
id: MAXO:0009025
label: cochlear device implantation
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
Cochlear implants were placed although the parents not that he has functionally derived no benefit.
explanation: >-
The report documents cochlear implantation but also reports absent
functional benefit, so this only partially supports hearing-directed
intervention.
- name: Gastrostomy and nutrition support
description: >-
Nutrition support, feeding therapy, and gastrostomy care may be required for
severe growth failure and feeding/GI complications.
treatment_term:
preferred_term: gastrostomy
term:
id: MAXO:0001346
label: gastrostomy
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Insufficient weight gain following surgery necessitated gastronomy tube placement.
explanation: >-
The source documents tube placement for persistent weight-gain failure;
the wording preserves the source's typographical error.
- name: Pulmonary mucus and airway support
description: >-
Respiratory management should address mucus plugging, airway obstruction, and
cystic-fibrosis-like pulmonary complications when present.
treatment_term:
preferred_term: respiratory tract agent therapy
term:
id: MAXO:0000312
label: respiratory tract agent therapy
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
mucus plugging and respiratory problems reminiscent of cystic fibrosis
explanation: >-
The evidence supports respiratory mucus complications but does not test a
specific pulmonary therapy, so treatment support is partial.
- name: Ocular and oral secretion support
description: >-
Supportive management should include care for absent tear production,
xerostomia, and related oral or ocular surface complications.
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
There was severe oral dryness and saliva was not able to be produced by massage of the salivary glands.
explanation: >-
The evidence supports the secretion problem targeted by supportive care,
but does not evaluate a specific treatment.
- name: Developmental rehabilitation and supportive care
description: >-
Children with Kilquist syndrome should receive developmental surveillance and
rehabilitation services tailored to profound global developmental
impairment and hypotonia.
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
Neuropsychological testing demonstrated profound delays in all developmental areas, with skills ranging from 1 to 6 months.
explanation: >-
The evidence supports the need for developmental support, but does not
provide outcome data for a specific rehabilitation program.
differential_diagnoses:
- name: Dominant SLC12A2-related cochleovestibular or neurodevelopmental disorder
description: >-
Heterozygous or de novo SLC12A2 variants can cause distinct dominant
phenotypes, including cochlea-restricted deafness with vestibular areflexia
and neurodevelopmental disorders. Those entities overlap genetically but are
not the biallelic Kilquist syndrome entity curated here.
distinguishing_features:
- Biallelic loss-of-function SLC12A2 variants with severe multisystem secretory and gastrointestinal involvement favor Kilquist syndrome.
- Heterozygous exon 21 or de novo variants with isolated cochleovestibular disease or a dominant neurodevelopmental presentation favor the separate dominant SLC12A2-related spectrum.
evidence:
- reference: PMID:40503591
reference_title: De Novo SLC12A2 Variant Presenting as Congenital Hearing Loss With Vestibular Areflexia.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Subsequently, several patients with severe developmental delay, sensorineural hearing loss, and bi-allelic loss of function variants were reported; this condition is known as Kilquist syndrome.
explanation: >-
This review-style introduction distinguishes the biallelic Kilquist
syndrome entity from other SLC12A2-linked phenotypes.
- reference: PMID:40503591
reference_title: De Novo SLC12A2 Variant Presenting as Congenital Hearing Loss With Vestibular Areflexia.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In 2020, heterozygous variants in SLC12A2 were identified as a cause of non-syndromic deafness associated with vestibular areflexia (DFNA78; MIM 619081).
explanation: >-
This supports a separate heterozygous cochleovestibular SLC12A2 condition
that should not be merged into Kilquist syndrome.
- reference: PMID:32658972
reference_title: SLC12A2 variants cause a neurodevelopmental disorder or cochleovestibular defect.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Through trio exome sequencing we identified de novo mutations in SLC12A2 in six children with neurodevelopmental disorders.
explanation: >-
This supports a distinct de novo heterozygous neurodevelopmental
SLC12A2-related spectrum.
- reference: PMID:32294086
reference_title: Variants encoding a restricted carboxy-terminal domain of SLC12A2 cause hereditary hearing loss in humans.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Using whole-exome analysis of three families with congenital, severe-to-profound hearing loss, we identified a missense variant of SLC12A2 in five affected members of one family showing a dominant inheritance mode, along with de novo splice-site and missense variants of SLC12A2 in two sporadic cases, as promising candidates associated with hearing loss.
explanation: >-
This supports dominant and de novo SLC12A2 hearing-loss presentations as a
differential scope issue rather than biallelic Kilquist syndrome.
- name: Cystic fibrosis
disease_term:
preferred_term: cystic fibrosis
term:
id: MONDO:0009061
label: cystic fibrosis
description: >-
Kilquist syndrome can resemble cystic fibrosis because of mucus plugging,
poor growth, and gastrointestinal symptoms, but it is distinguished by
profound congenital hearing loss and biallelic SLC12A2 deficiency.
distinguishing_features:
- Profound sensorineural hearing loss and absent salivation favor Kilquist syndrome.
- Positive CFTR-associated testing and classic pancreatic-pulmonary phenotype favor cystic fibrosis.
- name: Usher syndrome
disease_term:
preferred_term: Usher syndrome
term:
id: MONDO:0019501
label: Usher syndrome
description: >-
Usher syndrome overlaps with Kilquist syndrome through congenital hearing
loss, but Kilquist syndrome is distinguished by severe gastrointestinal and
secretory epithelial dysfunction rather than retinitis pigmentosa.
distinguishing_features:
- Global developmental delay and absent epithelial secretions favor Kilquist syndrome.
- Progressive retinopathy with deafblindness favors Usher syndrome.
clinical_trials: []
datasets:
- accession: PMID:30740830
title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
description: >-
Foundational human case-based dataset defining Kilquist syndrome through
deep clinical phenotyping, genomic diagnosis, and fibroblast-based
functional validation of complete NKCC1 loss.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
sample_count: 1
conditions:
- Kilquist syndrome
- homozygous SLC12A2 deletion
publication: PMID:30740830
evidence:
- reference: PMID:30740830
reference_title: "Kilquist syndrome: A novel syndromic hearing loss disorder caused by homozygous deletion of SLC12A2."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Herein we describe a child admitted to the NIH Undiagnosed Diseases Program with global developmental delay, sensorineural hearing loss, gastrointestinal abnormalities, and absent salivation.
explanation: >-
This supports the publication as the foundational disease-defining human
phenotype dataset for Kilquist syndrome.
notes: >-
Asta deep research was run as requested, but final curation relied on direct
review of PubMed references because the retrieval output was noisy and only
partially disease-specific. The entry is intentionally scoped to biallelic
Kilquist syndrome / OMIM 619080, with phenotypic claims treated as case-based
because only a small number of molecularly confirmed biallelic cases have been
reported. Heterozygous or de novo SLC12A2-related cochleovestibular and
neurodevelopmental disorders are documented separately as a differential
scope issue rather than as Kilquist syndrome subtypes.
This report is retrieval-only and is generated directly from Asta results.
search_papers_by_relevance with snippet_search.