Senior-Loken syndrome (SLSN) is a rare autosomal recessive oculo-renal ciliopathy defined by the association of nephronophthisis (a chronic tubulointerstitial cystic kidney disease that progresses to end-stage renal disease) with a retinitis pigmentosa-like retinal dystrophy. It is genetically heterogeneous: the causative genes — including NPHP1, IQCB1 (NPHP5), CEP290 (NPHP6), SDCCAG8, WDR19, and others — all encode proteins of the primary cilium, its basal body, or the transition zone. The shared molecular lesion is dysfunction of the ciliary transition zone in renal tubular monocilia and of the photoreceptor connecting cilium, which simultaneously produces the renal and retinal arms of the disease. SLSN therefore sits within the nephronophthisis-related ciliopathy spectrum and overlaps clinically and genetically with Joubert, Bardet-Biedl, and Leber congenital amaurosis phenotypes (notably through pleiotropic genes such as CEP290).
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Conditions with similar clinical presentations that must be differentiated from Senior-Loken Syndrome:
name: Senior-Loken Syndrome
creation_date: "2026-06-17T12:00:00Z"
category: Mendelian
description: >-
Senior-Loken syndrome (SLSN) is a rare autosomal recessive oculo-renal
ciliopathy defined by the association of nephronophthisis (a chronic
tubulointerstitial cystic kidney disease that progresses to end-stage renal
disease) with a retinitis pigmentosa-like retinal dystrophy. It is genetically
heterogeneous: the causative genes — including NPHP1, IQCB1 (NPHP5), CEP290
(NPHP6), SDCCAG8, WDR19, and others — all encode proteins of the primary
cilium, its basal body, or the transition zone. The shared molecular lesion is
dysfunction of the ciliary transition zone in renal tubular monocilia and of
the photoreceptor connecting cilium, which simultaneously produces the renal
and retinal arms of the disease. SLSN therefore sits within the
nephronophthisis-related ciliopathy spectrum and overlaps clinically and
genetically with Joubert, Bardet-Biedl, and Leber congenital amaurosis
phenotypes (notably through pleiotropic genes such as CEP290).
disease_term:
preferred_term: Senior-Loken syndrome
term:
id: MONDO:0017842
label: Senior-Loken syndrome
parents:
- Ciliopathies
has_subtypes:
- name: SLSN1
display_name: Senior-Loken syndrome 1 (NPHP1)
subtype_term:
preferred_term: Senior-Loken syndrome 1
term:
id: MONDO:0009962
label: Senior-Loken syndrome 1
description: >-
NPHP1-related Senior-Loken syndrome, caused by mutations (most often the
recurrent homozygous deletion) in NPHP1 encoding nephrocystin-1. NPHP1 is the
same gene whose loss causes isolated juvenile nephronophthisis; the
renal-retinal SLSN1 phenotype reflects additional involvement of the
photoreceptor connecting cilium.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "NPHP1 | nephrocystin 1 | hgnc:7905 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists NPHP1 among the disease-causing genes of Senior-Loken
syndrome, corresponding to the SLSN1 leaf class MONDO:0009962.
- name: SLSN5
display_name: Senior-Loken syndrome 5 (IQCB1/NPHP5)
subtype_term:
preferred_term: Senior-Loken syndrome 5
term:
id: MONDO:0012225
label: Senior-Loken syndrome 5
description: >-
IQCB1 (NPHP5)-related Senior-Loken syndrome. IQCB1 encodes nephrocystin-5, an
IQ-domain protein that interacts with RPGR and calmodulin at the photoreceptor
connecting cilium and renal primary cilium. IQCB1 was identified as the most
frequent cause of SLSN, and all reported individuals with IQCB1 mutations have
retinitis pigmentosa.
evidence:
- reference: PMID:15723066
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
we identify, by positional cloning, mutations in an evolutionarily
conserved gene, IQCB1 (also called NPHP5), as the most frequent cause of
SLSN. IQCB1 encodes an IQ-domain protein, nephrocystin-5. All individuals
with IQCB1 mutations have retinitis pigmentosa
explanation: >-
Identifies IQCB1/NPHP5 as the most frequent cause of Senior-Loken syndrome
(SLSN5, MONDO:0012225), with fully penetrant retinitis pigmentosa.
- name: SLSN6
display_name: Senior-Loken syndrome 6 (CEP290/NPHP6)
subtype_term:
preferred_term: Senior-Loken syndrome 6
term:
id: MONDO:0012433
label: Senior-Loken syndrome 6
description: >-
CEP290 (NPHP6)-related Senior-Loken syndrome. CEP290 encodes a large
centrosomal/transition-zone protein; its allelic spectrum is strikingly
pleiotropic, also causing Leber congenital amaurosis, Joubert syndrome, and
Meckel syndrome, illustrating how the same ciliary gene can produce
predominantly renal, retinal, or syndromic ciliopathy phenotypes.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "CEP290 | centrosomal protein 290 | hgnc:29021 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists CEP290 among the disease-causing genes of Senior-Loken
syndrome, corresponding to the SLSN6 leaf class MONDO:0012433.
- reference: PMID:16909394
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
CEP290 mutations therefore represent one of the most frequent causes of LCA
identified so far
explanation: >-
Documents the pleiotropy of CEP290, which also causes Leber congenital
amaurosis, relevant to the retinal arm and differential diagnosis of
CEP290-related Senior-Loken syndrome.
- name: SLSN7
display_name: Senior-Loken syndrome 7 (SDCCAG8)
subtype_term:
preferred_term: Senior-Loken syndrome 7
term:
id: MONDO:0013326
label: Senior-Loken syndrome 7
description: >-
SDCCAG8-related Senior-Loken syndrome. SDCCAG8 encodes a centrosomal protein
involved in ciliogenesis and Sonic hedgehog signaling; biallelic mutations
cause a retinal-renal ciliopathy that can extend to additional Bardet-Biedl-
like features.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "SDCCAG8 | SHH signaling and ciliogenesis regulator SDCCAG8 | hgnc:10671 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists SDCCAG8 among the disease-causing genes of Senior-Loken
syndrome, corresponding to the SLSN7 leaf class MONDO:0013326.
- name: SLSN8
display_name: Senior-Loken syndrome 8 (WDR19)
subtype_term:
preferred_term: Senior-Loken syndrome 8
term:
id: MONDO:0014579
label: Senior-Loken syndrome 8
description: >-
WDR19-related Senior-Loken syndrome. WDR19 encodes an intraflagellar
transport-A (IFT-A) complex subunit; its mutations cause a spectrum of
ciliopathies that includes the renal-retinal Senior-Loken phenotype as well
as skeletal ciliopathies.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "WDR19 | WD repeat domain 19 | hgnc:18340 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists WDR19 among the disease-causing genes of Senior-Loken
syndrome, corresponding to the SLSN8 leaf class MONDO:0014579.
inheritance:
- name: Autosomal Recessive
description: >-
Senior-Loken syndrome is inherited in an autosomal recessive manner; affected
individuals carry biallelic (homozygous or compound heterozygous) mutations
in one of the causative ciliary genes.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "A rare autosomal recessive oculo-renal ciliopathy characterized by the association of nephronophthisis (NPHP), a chronic kidney disease, with retinal dystrophy."
explanation: >-
Orphanet's definition establishes autosomal recessive inheritance of the
renal-retinal ciliopathy.
- reference: PMID:40427560
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Senior-Loken syndrome (SLSN) is a group of rare autosomal recessive
disorders caused by dysfunction of the primary cilium
explanation: >-
Confirms autosomal recessive inheritance and the primary-cilium basis of
the disorder. (Source is a narrative review; classified as OTHER.)
prevalence:
- population: Worldwide
measure_type: POINT_PREVALENCE
prevalence_class: BAND_1_9_PER_1000000
rate_low: 0.1
rate_high: 0.9
percentage: 1-9 per 1,000,000
notes: >-
Orphanet records a worldwide point prevalence of 1-9 per 1,000,000 for
Senior-Loken syndrome, consistent with its classification as a rare disorder.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "1-9 / 1 000 000 | Worldwide | Point prevalence"
explanation: >-
Orphanet's epidemiology table gives the worldwide point prevalence of
Senior-Loken syndrome.
pathophysiology:
- name: Ciliary Transition Zone Dysfunction
conforms_to: "ciliopathy_dysfunction#Basal Body and Transition Zone Dysfunction"
description: >-
The unifying upstream lesion of Senior-Loken syndrome is dysfunction of the
ciliary base. The nephrocystin proteins encoded by the SLSN genes localize to
the transition zone of renal and respiratory cilia and to the photoreceptor
connecting cilium, where they gate ciliary membrane composition and
bidirectional cargo transport. Loss of these proteins produces a structurally
present but functionally incompetent cilium that cannot correctly
compartmentalize signaling and phototransduction machinery, biasing the
downstream phenotype toward the renal tubule and the photoreceptor.
biological_processes:
- preferred_term: cilium assembly
term:
id: GO:0060271
label: cilium assembly
modifier: ABNORMAL
- preferred_term: protein localization to cilium
term:
id: GO:0061512
label: protein localization to cilium
modifier: ABNORMAL
- preferred_term: intraflagellar transport
term:
id: GO:0042073
label: intraciliary transport
modifier: ABNORMAL
cellular_components:
- preferred_term: ciliary transition zone
term:
id: GO:0035869
label: ciliary transition zone
- preferred_term: primary cilium
term:
id: GO:0005929
label: cilium
cell_types:
- preferred_term: ciliated cell
term:
id: CL:0000064
label: ciliated cell
downstream:
- target: Renal Tubular Cystic and Fibrotic Disease
description: >-
Transition-zone dysfunction in renal tubular monocilia drives the
nephronophthisis arm of the disease.
- target: Photoreceptor Connecting Cilium Degeneration
description: >-
Connecting-cilium dysfunction impairs photoreceptor outer-segment
maintenance, driving the retinal-dystrophy arm of the disease.
- target: Global Developmental Delay
description: Pleiotropic transition-zone and centrosomal ciliopathy genes can extend the Senior-Loken phenotype to neurodevelopmental delay.
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0001263 | Global developmental delay | Very frequent (99-80%)"
explanation: Orphanet records global developmental delay as a very frequent feature of Senior-Loken syndrome.
- target: Ataxia
description: Extended nephronophthisis-related ciliopathy phenotypes can include cerebellar/coordination involvement.
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0001251 | Ataxia | Occasional (29-5%)"
explanation: Orphanet records ataxia as an occasional feature of Senior-Loken syndrome.
- target: Premature Ovarian Insufficiency
description: Senior-Loken syndrome can include reproductive involvement; the precise ciliary intermediate remains unresolved.
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0008209 | Premature ovarian insufficiency | Frequent (79-30%)"
explanation: Orphanet records premature ovarian insufficiency as a frequent Senior-Loken syndrome feature.
evidence:
- reference: PMID:16885411
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
nephrocystin specifically localizes at the ciliary base to the transition
zone of renal and respiratory cilia and to photoreceptor connecting cilia
explanation: >-
Localizes nephrocystin to the transition zone of renal cilia and the
photoreceptor connecting cilium, the shared cellular lesion of Senior-Loken
syndrome and the basis for conformance to the transition-zone module node.
- reference: PMID:15723066
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
these proteins localize to connecting cilia of photoreceptors and to
primary cilia of renal epithelial cells
explanation: >-
Nephrocystin-5 (IQCB1) and its partners localize to both the photoreceptor
connecting cilium and renal primary cilium, linking the two affected
compartments to a common ciliary lesion.
- name: Renal Tubular Cystic and Fibrotic Disease
conforms_to: "ciliopathy_dysfunction#Renal Tubular Cystic and Fibrotic Disease"
description: >-
Renal tubular epithelial cells use the primary cilium as a flow and signaling
sensor that maintains tubular architecture. Ciliary dysfunction produces the
nephronophthisis phenotype: a chronic tubulointerstitial nephropathy with
corticomedullary cysts, tubular basement membrane disruption, and
interstitial fibrosis that progresses to end-stage renal disease, typically
in childhood or adolescence. Nephronophthisis is the leading genetic cause of
end-stage renal failure in children.
biological_processes:
- preferred_term: cilium assembly
term:
id: GO:0060271
label: cilium assembly
modifier: ABNORMAL
cell_types:
- preferred_term: kidney tubule epithelial cell
term:
id: CL:0002518
label: kidney epithelial cell
locations:
- preferred_term: kidney
term:
id: UBERON:0002113
label: kidney
evidence:
- reference: PMID:21071979
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Nephronophthisis is a recessive disorder of the kidney that is the leading
cause of end-stage renal failure in children.
explanation: >-
Establishes nephronophthisis, the renal arm of Senior-Loken syndrome, as a
recessive ciliopathy and the leading genetic cause of pediatric end-stage
renal failure.
- reference: PMID:16885411
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
nephrocystin deficiency or dysfunction at the transition zone of renal
monocilia and the photoreceptor connecting cilium might explain renal
failure and retinal degeneration that are observed in patients with NPHP1
explanation: >-
Directly links transition-zone dysfunction in renal monocilia to the renal
failure of nephronophthisis.
downstream:
- target: Nephronophthisis
description: Renal tubular ciliary dysfunction produces the nephronophthisis component of Senior-Loken syndrome.
causal_link_type: DIRECT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000090 | Nephronophthisis | Frequent (79-30%)"
explanation: Orphanet records nephronophthisis as a frequent Senior-Loken syndrome feature.
- target: Tubulointerstitial Fibrosis
description: The nephronophthisis renal lesion includes interstitial fibrosis and tubular atrophy.
causal_link_type: DIRECT
evidence:
- reference: PMID:23559409
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In renal histology, the most prominent features of NPHP are tubular atrophy, basement membrane disintegration, interstitial fibrosis, and cyst formation."
explanation: The large NPHP-RC cohort paper describes tubulointerstitial fibrosis as a prominent nephronophthisis histologic feature.
- target: Stage 5 Chronic Kidney Disease
description: Progressive nephronophthisis causes end-stage renal disease in childhood or adolescence.
causal_link_type: DIRECT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0003774 | Stage 5 chronic kidney disease | Very frequent (99-80%)"
explanation: Orphanet records stage 5 chronic kidney disease as very frequent in Senior-Loken syndrome.
- target: Hypertension
description: Progressive chronic kidney disease in Senior-Loken syndrome can lead to hypertension.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000822 | Hypertension | Very frequent (99-80%)"
explanation: Orphanet records hypertension as a very frequent Senior-Loken syndrome feature.
- target: Short Stature
description: Pediatric chronic kidney disease contributes to growth impairment and short stature.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0004322 | Short stature | Very frequent (99-80%)"
explanation: Orphanet records short stature as a very frequent Senior-Loken syndrome feature.
- name: Photoreceptor Connecting Cilium Degeneration
conforms_to: "ciliopathy_dysfunction#Photoreceptor Connecting Cilium Degeneration"
description: >-
Photoreceptor outer segments are specialized non-motile sensory cilia
connected to the cell body by the connecting cilium, through which all
phototransduction cargo is trafficked. In Senior-Loken syndrome, nephrocystin
dysfunction at the connecting cilium impairs outer-segment morphogenesis and
maintenance, causing progressive photoreceptor death and a retinitis
pigmentosa-like retinal dystrophy. Retinal involvement is highly penetrant and
is the feature that distinguishes Senior-Loken syndrome from isolated
nephronophthisis.
biological_processes:
- preferred_term: photoreceptor cell maintenance
term:
id: GO:0045494
label: photoreceptor cell maintenance
modifier: DECREASED
cell_types:
- preferred_term: photoreceptor cell
term:
id: CL:0000210
label: photoreceptor cell
locations:
- preferred_term: retina
term:
id: UBERON:0000966
label: retina
evidence:
- reference: PMID:15723066
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Ten percent of affected individuals have retinitis pigmentosa, constituting
the renal-retinal Senior-Loken syndrome (SLSN).
explanation: >-
Defines the retinal arm (retinitis pigmentosa) that, combined with
nephronophthisis, constitutes Senior-Loken syndrome.
downstream:
- target: Retinal Dystrophy
description: Photoreceptor connecting-cilium dysfunction causes the retinitis-pigmentosa-like retinal dystrophy.
causal_link_type: DIRECT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000556 | Retinal dystrophy | Very frequent (99-80%)"
explanation: Orphanet records retinal dystrophy as a very frequent Senior-Loken syndrome feature.
- target: Visual Impairment
description: Progressive photoreceptor degeneration results in visual impairment.
causal_link_type: DIRECT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000505 | Visual impairment | Very frequent (99-80%)"
explanation: Orphanet records visual impairment as a very frequent feature.
- target: Progressive Visual Loss
description: Retinal dystrophy advances over time, producing progressive visual loss.
causal_link_type: DIRECT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000529 | Progressive visual loss | Frequent (79-30%)"
explanation: Orphanet records progressive visual loss as a frequent feature.
- target: Abnormal Retinal Pigmentation
description: The retinitis-pigmentosa-like retinal dystrophy includes pigmentary retinal changes.
causal_link_type: DIRECT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0007703 | Abnormality of retinal pigmentation | Very frequent (99-80%)"
explanation: Orphanet records abnormal retinal pigmentation as a very frequent feature.
phenotypes:
- name: Nephronophthisis
category: Renal
description: >-
Nephronophthisis — a chronic tubulointerstitial cystic kidney disease — is
the obligate renal component of Senior-Loken syndrome.
phenotype_term:
preferred_term: Nephronophthisis
term:
id: HP:0000090
label: Nephronophthisis
frequency: FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000090 | Nephronophthisis | Frequent (79-30%)"
explanation: >-
Orphanet records nephronophthisis as a frequent feature of Senior-Loken
syndrome; frequency band Frequent (79-30%) maps to FREQUENT.
- name: Retinal Dystrophy
category: Ophthalmologic
description: >-
A retinitis pigmentosa-like retinal dystrophy is the defining ocular
component of Senior-Loken syndrome, reflecting photoreceptor connecting-cilium
dysfunction.
phenotype_term:
preferred_term: Retinal dystrophy
term:
id: HP:0000556
label: Retinal dystrophy
frequency: VERY_FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000556 | Retinal dystrophy | Very frequent (99-80%)"
explanation: >-
Orphanet records retinal dystrophy as a very frequent feature; frequency
band Very frequent (99-80%) maps to VERY_FREQUENT.
- name: Visual Impairment
category: Ophthalmologic
description: >-
Visual impairment results from progressive retinal degeneration and is a
near-universal feature of Senior-Loken syndrome.
phenotype_term:
preferred_term: Visual impairment
term:
id: HP:0000505
label: Visual impairment
frequency: VERY_FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000505 | Visual impairment | Very frequent (99-80%)"
explanation: >-
Orphanet records visual impairment as a very frequent feature; band Very
frequent (99-80%) maps to VERY_FREQUENT.
- name: Progressive Visual Loss
category: Ophthalmologic
description: >-
Vision typically declines progressively as the retinal dystrophy advances.
phenotype_term:
preferred_term: Progressive visual loss
term:
id: HP:0000529
label: Progressive visual loss
frequency: FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000529 | Progressive visual loss | Frequent (79-30%)"
explanation: >-
Orphanet records progressive visual loss as a frequent feature; band
Frequent (79-30%) maps to FREQUENT.
- name: Abnormal Retinal Pigmentation
category: Ophthalmologic
description: >-
Retinal pigmentary changes typical of a retinitis pigmentosa-like dystrophy
are seen on fundus examination.
phenotype_term:
preferred_term: Abnormal retinal pigmentation
term:
id: HP:0007703
label: Abnormal retinal pigmentation
frequency: VERY_FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0007703 | Abnormality of retinal pigmentation | Very frequent (99-80%)"
explanation: >-
Orphanet records abnormal retinal pigmentation as a very frequent feature;
band Very frequent (99-80%) maps to VERY_FREQUENT.
- name: Stage 5 Chronic Kidney Disease
category: Renal
description: >-
Nephronophthisis in Senior-Loken syndrome progresses to stage 5 chronic
kidney disease (end-stage renal disease), typically in childhood or
adolescence, requiring renal replacement therapy.
phenotype_term:
preferred_term: Stage 5 chronic kidney disease
term:
id: HP:0003774
label: Stage 5 chronic kidney disease
frequency: VERY_FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0003774 | Stage 5 chronic kidney disease | Very frequent (99-80%)"
explanation: >-
Orphanet records stage 5 chronic kidney disease as a very frequent feature;
band Very frequent (99-80%) maps to VERY_FREQUENT.
- name: Tubulointerstitial Fibrosis
category: Renal
description: >-
The nephronophthisis renal lesion includes tubular atrophy, basement
membrane disruption, interstitial fibrosis, and cyst formation.
phenotype_term:
preferred_term: Tubulointerstitial fibrosis
term:
id: HP:0005576
label: Tubulointerstitial fibrosis
evidence:
- reference: PMID:23559409
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In renal histology, the most prominent features of NPHP are tubular atrophy, basement membrane disintegration, interstitial fibrosis, and cyst formation."
explanation: This large NPHP-RC cohort paper identifies interstitial fibrosis as a prominent histologic feature of nephronophthisis-related ciliopathies.
- name: Global Developmental Delay
category: Neurologic
description: >-
A subset of patients, particularly those with pleiotropic transition-zone
genes, show global developmental delay as part of an extended ciliopathy
phenotype.
phenotype_term:
preferred_term: Global developmental delay
term:
id: HP:0001263
label: Global developmental delay
frequency: VERY_FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0001263 | Global developmental delay | Very frequent (99-80%)"
explanation: >-
Orphanet records global developmental delay as a very frequent feature;
band Very frequent (99-80%) maps to VERY_FREQUENT.
- name: Ataxia
category: Neurologic
description: >-
Ataxia can occur in Senior-Loken syndrome, reflecting overlap with the
cerebellar involvement of related ciliopathies such as Joubert syndrome.
phenotype_term:
preferred_term: Ataxia
term:
id: HP:0001251
label: Ataxia
frequency: OCCASIONAL
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0001251 | Ataxia | Occasional (29-5%)"
explanation: >-
Orphanet records ataxia as an occasional feature; band Occasional (29-5%)
maps to OCCASIONAL.
- name: Hypertension
category: Cardiovascular
description: >-
Hypertension occurs as a frequent complication of chronic kidney disease in
Senior-Loken syndrome, reflecting the progressive renal impairment of
nephronophthisis.
phenotype_term:
preferred_term: Hypertension
term:
id: HP:0000822
label: Hypertension
frequency: VERY_FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0000822 | Hypertension | Very frequent (99-80%)"
explanation: >-
Orphanet records hypertension as a very frequent feature; band Very
frequent (99-80%) maps to VERY_FREQUENT.
- name: Short Stature
category: Growth
description: >-
Short stature occurs in many children with Senior-Loken syndrome as a
consequence of pediatric chronic kidney disease and its associated growth
impairment.
phenotype_term:
preferred_term: Short stature
term:
id: HP:0004322
label: Short stature
frequency: VERY_FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0004322 | Short stature | Very frequent (99-80%)"
explanation: >-
Orphanet records short stature as a very frequent feature; band Very
frequent (99-80%) maps to VERY_FREQUENT.
- name: Premature Ovarian Insufficiency
category: Reproductive
description: >-
Premature ovarian insufficiency occurs as a frequent extrarenal, extra-ocular
manifestation in Senior-Loken syndrome, reflecting ciliary dysfunction in
ovarian follicle development.
phenotype_term:
preferred_term: Premature ovarian insufficiency
term:
id: HP:0008209
label: Premature ovarian insufficiency
frequency: FREQUENT
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "HP:0008209 | Premature ovarian insufficiency | Frequent (79-30%)"
explanation: >-
Orphanet records premature ovarian insufficiency as a frequent feature;
band Frequent (79-30%) maps to FREQUENT.
genetic:
- name: NPHP1
association: Causative
gene_term:
preferred_term: NPHP1
term:
id: hgnc:7905
label: NPHP1
notes: >-
Biallelic NPHP1 mutations (commonly the recurrent homozygous deletion) cause
SLSN1; NPHP1 also causes isolated juvenile nephronophthisis.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "NPHP1 | nephrocystin 1 | hgnc:7905 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists NPHP1 as a disease-causing gene of Senior-Loken syndrome.
- name: IQCB1
association: Causative
gene_term:
preferred_term: IQCB1
term:
id: hgnc:28949
label: IQCB1
notes: >-
IQCB1 (NPHP5) encodes nephrocystin-5 and was identified as the most frequent
cause of Senior-Loken syndrome; all reported IQCB1 patients have retinitis
pigmentosa.
evidence:
- reference: PMID:15723066
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
we identify, by positional cloning, mutations in an evolutionarily
conserved gene, IQCB1 (also called NPHP5), as the most frequent cause of
SLSN. IQCB1 encodes an IQ-domain protein, nephrocystin-5. All individuals
with IQCB1 mutations have retinitis pigmentosa
explanation: >-
Original identification of IQCB1/NPHP5 as the most frequent cause of
Senior-Loken syndrome, with fully penetrant retinitis pigmentosa.
- name: CEP290
association: Causative
gene_term:
preferred_term: CEP290
term:
id: hgnc:29021
label: CEP290
notes: >-
CEP290 (NPHP6) encodes a transition-zone protein; its highly pleiotropic
allelic spectrum spans Senior-Loken syndrome, Leber congenital amaurosis,
Joubert syndrome, and Meckel syndrome.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "CEP290 | centrosomal protein 290 | hgnc:29021 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists CEP290 as a disease-causing gene of Senior-Loken syndrome.
- name: SDCCAG8
association: Causative
gene_term:
preferred_term: SDCCAG8
term:
id: hgnc:10671
label: SDCCAG8
notes: >-
SDCCAG8 encodes a centrosomal protein involved in ciliogenesis and Sonic
hedgehog signaling; biallelic mutations cause SLSN7.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "SDCCAG8 | SHH signaling and ciliogenesis regulator SDCCAG8 | hgnc:10671 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists SDCCAG8 as a disease-causing gene of Senior-Loken syndrome.
- name: WDR19
association: Causative
gene_term:
preferred_term: WDR19
term:
id: hgnc:18340
label: WDR19
notes: >-
WDR19 encodes an intraflagellar transport-A (IFT-A) complex subunit; mutations
cause SLSN8 within a broader WDR19 ciliopathy spectrum.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "WDR19 | WD repeat domain 19 | hgnc:18340 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists WDR19 as a disease-causing gene of Senior-Loken syndrome.
- name: NPHP3
association: Causative
gene_term:
preferred_term: NPHP3
term:
id: hgnc:7907
label: NPHP3
notes: >-
NPHP3 (nephrocystin-3) mutations cause SLSN3; NPHP3 is a component of the
nephronophthisis protein network at the ciliary transition zone.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "NPHP3 | nephrocystin 3 | hgnc:7907 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists NPHP3 as a disease-causing gene of Senior-Loken syndrome.
- name: NPHP4
association: Causative
gene_term:
preferred_term: NPHP4
term:
id: hgnc:19104
label: NPHP4
notes: >-
NPHP4 (nephrocystin-4/nephroretinin) mutations cause SLSN4; NPHP4 forms a
complex with NPHP1 at the ciliary transition zone.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "NPHP4 | nephrocystin 4 | hgnc:19104 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists NPHP4 as a disease-causing gene of Senior-Loken syndrome.
- name: INVS
association: Causative
gene_term:
preferred_term: INVS
term:
id: hgnc:17870
label: INVS
notes: >-
INVS (inversin) mutations cause nephronophthisis type 2 / SLSN; inversin
shuttles between the cilium and cell junctions to coordinate developmental
pathways.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "INVS | inversin | hgnc:17870 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists INVS as a disease-causing gene of Senior-Loken syndrome.
- name: CEP164
association: Causative
gene_term:
preferred_term: CEP164
term:
id: hgnc:29182
label: CEP164
notes: >-
CEP164 is a distal appendage protein that anchors transition-zone components
and is required for ciliogenesis; mutations cause SLSN10.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "CEP164 | centrosomal protein 164 | hgnc:29182 | Disease-causing germline mutation(s) in"
explanation: >-
Orphanet lists CEP164 as a disease-causing gene of Senior-Loken syndrome.
- name: TRAF3IP1
association: Causative
gene_term:
preferred_term: TRAF3IP1
term:
id: hgnc:17861
label: TRAF3IP1
notes: >-
TRAF3IP1 encodes IFT54, an intraflagellar transport B complex protein;
loss-of-function mutations cause SLSN9 within a spectrum of ciliopathies.
evidence:
- reference: ORPHA:3156
supports: SUPPORT
snippet: "TRAF3IP1 | TRAF3 interacting protein 1 | hgnc:17861 | Disease-causing germline mutation(s) (loss of function) in"
explanation: >-
Orphanet lists TRAF3IP1 as a disease-causing gene of Senior-Loken syndrome.
diagnosis:
- name: Clinical and Molecular Diagnosis
description: >-
Senior-Loken syndrome is suspected when nephronophthisis (chronic kidney
disease with corticomedullary cysts) co-occurs with a retinitis
pigmentosa-like retinal dystrophy, and is confirmed by identification of
biallelic pathogenic variants in one of the SLSN ciliary genes. Because of
marked genetic and phenotypic overlap with other ciliopathies, molecular
genetic testing (gene panel or exome) is central to establishing a definitive
diagnosis.
diagnosis_term:
preferred_term: molecular genetic testing
term:
id: MAXO:0000533
label: molecular genetic testing
evidence:
- reference: PMID:40427560
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Due to the genetic heterogeneity and significant phenotypic overlap with
other ciliopathies, establishing a definitive diagnosis during the initial
consultation remains a challenge for clinicians.
explanation: >-
Establishes that genetic heterogeneity and phenotypic overlap drive the
need for molecular diagnosis in Senior-Loken syndrome. (Source is a narrative review; classified as OTHER.)
differential_diagnoses:
- name: Isolated Nephronophthisis
description: >-
Isolated (non-syndromic) nephronophthisis shares the renal phenotype and
causative genes but lacks the retinal dystrophy that defines Senior-Loken
syndrome; retinal involvement occurs in roughly 10% of nephronophthisis
patients, constituting SLSN.
evidence:
- reference: PMID:15723066
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Ten percent of affected individuals have retinitis pigmentosa, constituting
the renal-retinal Senior-Loken syndrome (SLSN).
explanation: >-
Distinguishes Senior-Loken syndrome from isolated nephronophthisis by the
presence of retinitis pigmentosa.
- name: Leber Congenital Amaurosis
description: >-
CEP290-related Leber congenital amaurosis shares a causative gene with
CEP290-related Senior-Loken syndrome but presents as an isolated early-onset
retinal dystrophy without nephronophthisis; CEP290 is one of the most frequent
causes of LCA.
evidence:
- reference: PMID:16909394
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
CEP290 mutations therefore represent one of the most frequent causes of LCA
identified so far
explanation: >-
Documents CEP290 as a frequent cause of Leber congenital amaurosis, the
retinal-only differential of CEP290-related Senior-Loken syndrome.
treatments:
- name: Renal Replacement Therapy
description: >-
Because nephronophthisis progresses to end-stage renal disease, management
centers on renal replacement therapy — dialysis and kidney transplantation —
once stage 5 chronic kidney disease is reached. There is no disease-modifying
therapy that halts the underlying ciliopathy.
treatment_term:
preferred_term: kidney transplantation
term:
id: MAXO:0010039
label: organ transplantation
- name: Low-Vision Supportive Care
description: >-
Ophthalmologic management is supportive, comprising low-vision rehabilitation
and visual aids for the progressive retinal dystrophy; no proven therapy
reverses the photoreceptor degeneration.
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
- name: Genetic Counseling
description: >-
Autosomal recessive inheritance entails a 25% sibling recurrence risk. Once
the biallelic variants are identified, carrier testing, prenatal testing, and
preimplantation genetic testing become available to families.
treatment_term:
preferred_term: Genetic Counseling
term:
id: NCIT:C15240
label: Genetic Counseling
review_notes: >-
Senior-Loken syndrome is a lumped renal-retinal ciliopathy entry created to
cover the SLSN1-9 gene-level MONDO leaf classes (per GitHub issue 4243) under the
umbrella term MONDO:0017842. Subtypes are represented as gene-level
has_subtypes rather than separate thin files, following the repository
convention for gene-numbered MONDO splits. The mechanism is anchored to the
ciliopathy_dysfunction module: transition-zone dysfunction (shared lesion)
bifurcating into the renal (nephronophthisis) and retinal (photoreceptor
connecting-cilium) arms. Initial evidence backbone is the Orphanet structured
record (ORPHA:3156) plus verified primary/review literature; additional
subtype-specific gene-discovery references and pathophysiology depth are
follow-up opportunities.
classifications:
harrisons_chapter:
- classification_value: KIDNEY_URINARY_TRACT
- classification_value: GENETICS_ENVIRONMENT_DISEASE
mechanistic_category:
- classification_value: ciliopathy
references:
- reference: PMID:15723066
title: "Nephrocystin-5, a ciliary IQ domain protein, is mutated in Senior-Loken syndrome and interacts with RPGR and calmodulin."
- reference: PMID:16885411
title: "Nephrocystin specifically localizes to the transition zone of renal and respiratory cilia and photoreceptor connecting cilia."
- reference: PMID:16909394
title: "Mutations in the CEP290 (NPHP6) gene are a frequent cause of Leber congenital amaurosis."
- reference: PMID:21071979
title: "Mechanisms of nephronophthisis and related ciliopathies."
- reference: PMID:40427560
title: "Senior-Loken Syndrome: Ocular Perspectives on Genetics, Pathogenesis, and Management."
- reference: ORPHA:3156
title: "Senior-Loken syndrome"