Boucher-Neuhauser Syndrome

Mendelian MONDO:0008980 Pathograph 32 Show in embeddings browser Hereditary Ataxia Congenital Hypogonadotropic Hypogonadism

Boucher-Neuhauser syndrome (BNS) is a rare autosomal recessive neurodegenerative disorder caused by biallelic pathogenic variants in PNPLA6, which encodes neuropathy target esterase (NTE). It is classically defined by the triad of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy, and is now recognized as one cluster on a continuous PNPLA6-disorder spectrum that also includes Gordon Holmes syndrome, Oliver-McFarlane syndrome, Laurence-Moon syndrome, and spastic paraplegia type 39. NTE is an endoplasmic-reticulum-associated phospholipase/esterase required for phospholipid (phosphatidylcholine/lysophospholipid) homeostasis; loss of NTE activity causes degeneration of cerebellar, retinal, and hypothalamic-pituitary neurons. Residual NTE activity correlates inversely with the presence of retinopathy and endocrinopathy.

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1
Inheritance
7
Pathophys.
23
Phenotypes
1
Gaps
32
Pathograph
1
Genes
3
Medical Actions
11
References
1
Deep Research
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Inheritance

1
Autosomal recessive inheritance HP:0000007
BNS is caused by biallelic (homozygous or compound heterozygous) pathogenic variants in PNPLA6 and is inherited in an autosomal recessive manner.
Autosomal recessive inheritance
Show evidence (2 references)
PMID:38683245 SUPPORT Human Clinical
"Boucher Neuhäuser Syndrome (BNS) is a rare disease with autosomal recessive inheritance defined by the classical triad; early-onset ataxia, hypogonadism and chorioretinal dystrophy."
Directly states the autosomal recessive inheritance pattern and the defining clinical triad.
PMID:25299038 SUPPORT Human Clinical
"PNPLA6 disorders are inherited in an autosomal recessive manner."
GeneReviews confirms autosomal recessive inheritance for the PNPLA6 disorder spectrum, which includes BNS.
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Discussions and Knowledge Gaps

1
Should Boucher-Neuhauser syndrome be curated primarily as a discrete triad syndrome or as one phenotypic cluster within a broader PNPLA6 neurodegenerative spectrum?
INTERPRETATION OPEN bns_pnpla6_spectrum_boundaries
Attached to
disease#Boucher-Neuhauser Syndrome genetic#PNPLA6
The triad remains clinically useful, but PNPLA6 case series increasingly show overlapping retinal, endocrine, cerebellar, pyramidal, and peripheral nerve features across named syndromes. Overcommitting to a rigid syndrome boundary would understate this allelic continuum.
Show evidence (1 reference)
PMID:24355708 SUPPORT Human Clinical
"Boucher-Neuhäuser and Gordon Holmes syndromes in fact represent phenotypic clusters on a spectrum of neurodegenerative diseases caused by mutations in PNPLA6."
The 2014 spectrum paper states the disease-boundary issue directly.
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Pathophysiology

7
Loss of neuropathy target esterase (NTE) activity
PNPLA6 encodes neuropathy target esterase (NTE), a patatin-like serine hydrolase on the cytoplasmic face of the endoplasmic reticulum with phospholipase/lysophospholipase activity. NTE deacylates glycerophospholipids and is central to phosphatidylcholine homeostasis. Biallelic pathogenic PNPLA6 variants, which cluster in the C-terminal phospholipase/esterase (patatin-like) domain, reduce NTE esterase activity, the principal loss-of-function mechanism underlying BNS.
PNPLA6 hgnc:16268 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves PNPLA6 (hgnc:16268). hgnc:16268 is a gene from the HUGO Gene Nomenclature Committee.
phospholipid metabolic process GO:0006644 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased phospholipid metabolic process (GO:0006644). GO:0006644 is a biological process from the Gene Ontology. ↓ DECREASED phosphatidylcholine metabolic process GO:0046470 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal phosphatidylcholine metabolic process (GO:0046470). GO:0046470 is a biological process from the Gene Ontology. ⚠ ABNORMAL
glycerophospholipase (NTE esterase) activity GO:0004620 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves decreased glycerophospholipase (NTE esterase) activity, annotated with glycerophospholipase activity (GO:0004620). GO:0004620 is a molecular function from the Gene Ontology. ↓ DECREASED carboxylic ester hydrolase activity GO:0052689 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves decreased carboxylic ester hydrolase activity (GO:0052689). GO:0052689 is a molecular function from the Gene Ontology. ↓ DECREASED
endoplasmic reticulum membrane GO:0005789 Gene Ontology (GO) Relation: this pathophysiological event involves this cellular component This pathophysiological event involves endoplasmic reticulum membrane (GO:0005789). GO:0005789 is a cellular component from the Gene Ontology.
Downstream
NTE-activity-dependent neurodegeneration of vulnerable tissues Reduced PNPLA6/NTE esterase activity produces the tissue-vulnerability phenotype continuum across PNPLA6 disorders.
Show evidence (2 references)
PMID:37732399 SUPPORT Human Clinical
"PNPLA6 encodes NTE, an enzyme involved in maintaining phospholipid homeostasis and trafficking in the nervous system."
Establishes NTE's role in phospholipid homeostasis whose disruption is the molecular basis of BNS.
PMID:38735647 SUPPORT Human Clinical
"Measuring esterase activity of 46 disease-associated and 20 common variants observed across PNPLA6-associated clinical diagnoses unambiguously reclassified 36 variants as pathogenic and 10 variants as likely pathogenic"
Demonstrates that disease-associated PNPLA6 variants reduce NTE esterase activity, supporting loss of enzymatic function as the mechanism.
NTE-activity-dependent neurodegeneration of vulnerable tissues
Reduced NTE activity disrupts phospholipid remodeling at ER membranes, rendering specific neuronal and supporting cell populations vulnerable to age-dependent degeneration: cerebellar Purkinje-cell circuits (ataxia), retinal photoreceptors and retinal pigment epithelium (chorioretinal dystrophy), and hypothalamic-pituitary neurons (hypogonadotropic hypogonadism / anterior hypopituitarism). Overall NTE activity is inversely related to the presence of retinopathy and endocrinopathy, defining a genotype:activity:phenotype continuum across PNPLA6 disorders. An allelic mouse series recapitulates an NTE activity threshold for retinal degeneration, with complete loss being embryonic lethal.
cerebellar Purkinje cell CL:0000121 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves cerebellar Purkinje cell, annotated with Purkinje cell (CL:0000121). CL:0000121 is a cell type from the Cell Ontology. retinal photoreceptor cell CL:0000210 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves retinal photoreceptor cell, annotated with photoreceptor cell (CL:0000210). CL:0000210 is a cell type from the Cell Ontology. retinal pigment epithelial cell CL:0002586 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves retinal pigment epithelial cell (CL:0002586). CL:0002586 is a cell type from the Cell Ontology.
neuron apoptotic process GO:0051402 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased neuron apoptotic process (GO:0051402). GO:0051402 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Cerebellar neuronal dysfunction Cerebellar neuronal vulnerability produces a cerebellar dysfunction cascade.
Cerebellar atrophy Cerebellar neurodegeneration is visible as cerebellar atrophy on MRI.
Hypothalamic-pituitary endocrine dysfunction Hypothalamic-pituitary vulnerability produces the endocrine phenotype cascade.
Anterior pituitary dysfunction Endocrine involvement can extend to an anterior-pituitary dysfunction cascade.
Chorioretinal degeneration Retinal vulnerability produces a chorioretinal degeneration cascade.
Peripheral axonal degeneration PNPLA6 neurodegenerative involvement can extend to peripheral axonal degeneration.
Spasticity Upper-motor-neuron involvement in PNPLA6 disorders can manifest as spasticity.
Cognitive impairment CNS involvement in the PNPLA6 spectrum includes cognitive impairment in a subset of patients.
Nystagmus Cerebellar and ocular involvement can produce nystagmus.
Show evidence (3 references)
PMID:38735647 SUPPORT Human Clinical
"Estimating the overall NTE activity of affected individuals revealed a striking inverse relationship between NTE activity and the presence of retinopathy and endocrinopathy."
Links reduced NTE activity quantitatively to the retinal and endocrine manifestations of the PNPLA6 spectrum that includes BNS.
PMID:38735647 SUPPORT Model Organism
"This phenomenon was recaptured in vivo in an allelic mouse series, where a similar NTE threshold for retinopathy exists."
An allelic mouse series recapitulates the NTE-activity threshold for retinal degeneration, supporting the causal chain in vivo.
PMID:35448471 SUPPORT Model Organism
"A conditional knockout of PNPLA6/NTE in the mouse brain results in age-related neurodegeneration, whereas a complete knockout causes lethality during embryogenesis due to defects in the development of the placenta."
Mouse models show that NTE loss causes age-related neurodegeneration and that complete loss is embryonic lethal, consistent with the human activity-threshold model.
Cerebellar neuronal dysfunction
PNPLA6-related cerebellar neuronal vulnerability produces cerebellar motor dysfunction with structural atrophy and clinical ataxia.
Downstream
Cerebellar ataxia Cerebellar neuronal dysfunction manifests as cerebellar ataxia.
Gait ataxia Cerebellar motor dysfunction produces gait ataxia.
Dysdiadochokinesia Cerebellar dysfunction impairs rapid alternating movements.
Scanning speech Cerebellar dysarthria can produce a scanning quality to speech.
Hypothalamic-pituitary endocrine dysfunction
Central endocrine dysfunction produces hypogonadotropic hypogonadism and its measured gonadotropin and sex-hormone consequences.
Downstream
Hypogonadotropic hypogonadism Central endocrine dysfunction manifests as hypogonadotropic hypogonadism.
Decreased circulating follicle stimulating hormone concentration Central gonadotropin deficiency can lower circulating FSH.
Decreased circulating luteinizing hormone level Central gonadotropin deficiency can lower circulating LH.
Decreased serum testosterone concentration Reduced gonadotropin signaling can lower testosterone in affected males.
Primary amenorrhea Gonadotropin deficiency can present as primary amenorrhea in affected females.
Anterior pituitary dysfunction
Anterior pituitary dysfunction can include growth hormone, thyroid hormone, and gonadotropin deficiencies.
Downstream
Anterior hypopituitarism The clinical endocrine syndrome is anterior hypopituitarism.
Growth hormone deficiency Anterior pituitary dysfunction can include growth hormone deficiency.
Hypothyroidism Anterior pituitary dysfunction can include thyroid hormone deficiency.
Reduced pituitary size on MRI Pituitary dysfunction can be accompanied by reduced pituitary size on MRI.
Chorioretinal degeneration
Retinal degeneration produces chorioretinal dystrophy, retinal atrophy, and visual impairment.
Downstream
Chorioretinal dystrophy Chorioretinal degeneration manifests as chorioretinal dystrophy.
Chorioretinal atrophy Progressive chorioretinal degeneration produces chorioretinal atrophy.
Retinal pigment epithelial atrophy Progressive retinal degeneration includes RPE atrophy.
Visual impairment Chorioretinal degeneration causes visual impairment.
Peripheral axonal degeneration
PNPLA6-related peripheral axonal degeneration produces neuropathy and reduced tendon reflexes.
Downstream
Peripheral axonal neuropathy Peripheral axonal degeneration manifests as axonal neuropathy.
Hyporeflexia Peripheral axonal neuropathy can manifest as reduced tendon reflexes.
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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Boucher-Neuhauser Syndrome Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
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Phenotypes

23
Endocrine 2
Hypogonadotropic hypogonadism VERY_FREQUENT HP:0000044 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hypogonadotropic hypogonadism (HP:0000044). HP:0000044 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:25267340 SUPPORT Human Clinical
"Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy."
Identifies hypogonadotropic hypogonadism as a defining component of the BNS triad.
PMID:25299038 SUPPORT Human Clinical
"hypogonadotropic hypogonadism (delayed puberty and lack of secondary sex characteristics)"
GeneReviews describes the clinical presentation of the hypogonadotropic hypogonadism characteristic of BNS.
Growth hormone deficiency Secondary growth hormone deficiency HP:0008240 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Secondary growth hormone deficiency (HP:0008240). HP:0008240 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35069422 SUPPORT Human Clinical
"Additional clinical features included hypogonadotropic hypogonadism (5/8), growth hormone deficiency (2/8), peripheral axonal neuropathy (4/8), cognitive impairment (3/8), chorioretinal dystrophy (2/8)"
The PNPLA6 cohort reports growth hormone deficiency in 2/8 patients.
Eye 4
Chorioretinal dystrophy VERY_FREQUENT HP:0001135 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Chorioretinal dystrophy (HP:0001135). HP:0001135 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:25267340 SUPPORT Human Clinical
"Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy."
Identifies chorioretinal dystrophy as a defining component of the BNS triad.
PMID:37732399 SUPPORT Human Clinical
"Retinal disease presents with a unique chorioretinal dystrophy that is phenotypically similar to choroideremia and Leber congenital amaurosis."
Characterizes the chorioretinal dystrophy and its choroideremia-like appearance in PNPLA6 disorders.
Retinal pigment epithelial atrophy HP:0007722 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Retinal pigment epithelial atrophy (HP:0007722). HP:0007722 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25267340 SUPPORT Human Clinical
"The ocular changes noted in B–N are distinctive in their pattern of progressive RPE and choriocapillaris atrophy, with macular changes in the posterior pole and mid-periphery of each eye."
The ocular description directly supports retinal pigment epithelial atrophy as part of the BNS retinal phenotype.
Visual impairment HP:0000505 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Visual impairment (HP:0000505). HP:0000505 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:38735647 SUPPORT Human Clinical
"Biallelic pathogenic variants in the PNPLA6 gene cause a broad spectrum of disorders leading to gait disturbance, visual impairment, anterior hypopituitarism and hair anomalies."
Lists visual impairment among the cardinal manifestations of PNPLA6 disorders, including BNS.
Nystagmus HP:0000639 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Nystagmus (HP:0000639). HP:0000639 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25267340 SUPPORT Human Clinical
"She had hypometric vertical and horizontal saccades, saccadic smooth pursuit, gaze-evoked nystagmus and poor visual suppression of vestibular ocular reflexes."
Documents gaze-evoked nystagmus and saccadic pursuit abnormalities in a molecularly confirmed BNS case.
Genitourinary 1
Primary amenorrhea HP:0000786 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Primary amenorrhea (HP:0000786). HP:0000786 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25267340 SUPPORT Human Clinical
"This 59-year-old woman, born to non-consanguineous parents from Spain and Italy, had normal development until adolescence, when it was noted that she had primary amenorrhea."
A molecularly confirmed BNS case shows primary amenorrhea as an early endocrine presentation.
Musculoskeletal 1
Spasticity OCCASIONAL HP:0001257 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Spasticity (HP:0001257). HP:0001257 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"upper motor neuron involvement manifesting as spasticity and/or brisk reflexes"
GeneReviews lists spasticity from upper motor neuron involvement among the features of the PNPLA6 spectrum.
Nervous System 4
Cerebellar ataxia VERY_FREQUENT HP:0001251 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Cerebellar ataxia, annotated with Ataxia (HP:0001251). HP:0001251 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:25267340 SUPPORT Human Clinical
"Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy."
Identifies cerebellar ataxia as a defining component of the BNS triad.
PMID:35069422 SUPPORT Human Clinical
"Cerebellar ataxia was observed in seven patients and spastic paraplegia in one patient."
In a cohort of eight biallelic PNPLA6 cases, cerebellar ataxia was present in 7/8, supporting it as a very frequent feature.
Gait ataxia HP:0002066 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Gait ataxia (HP:0002066). HP:0002066 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25267340 SUPPORT Human Clinical
"Gait ataxia in Boucher-Neuhäuser usually manifests before early adulthood, although onset in the third or fourth decade has also been reported."
This molecularly confirmed case report identifies gait ataxia as the usual clinical manifestation of BNS cerebellar disease.
Cerebellar atrophy FREQUENT HP:0001272 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Cerebellar atrophy (HP:0001272). HP:0001272 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:35069422 SUPPORT Human Clinical
"Brain MRI showed cerebellar atrophy in 6/8 patients, more pronounced in superior and dorsal vermis lobules (I to VII)."
Documents cerebellar atrophy with characteristic superior/dorsal vermian predominance in PNPLA6 patients.
PMID:31135245 SUPPORT Human Clinical
"Hypogonadotropic hypogonadism and cerebellar vermis hypoplasia by MRI confirmed a diagnosis of Boucher-Neuhäuser syndrome."
Cerebellar vermis involvement on MRI contributed to the BNS diagnosis in a molecularly confirmed case.
Cognitive impairment OCCASIONAL HP:0100543 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Cognitive impairment (HP:0100543). HP:0100543 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"impaired cognitive functioning (learning disabilities in children; deficits in attention, visuospatial abilities, and recall in adults)"
GeneReviews documents cognitive impairment as a less frequent feature of PNPLA6 disorders.
Other 11
Dysdiadochokinesia Dysdiadochokinesis HP:0002075 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Dysdiadochokinesia, annotated with Dysdiadochokinesis (HP:0002075). HP:0002075 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25267340 SUPPORT Human Clinical
"She had dysdiadochokinesia in her arms and legs, dysmetria on heel-to-shin but not on finger-to-nose, and significant overshoot on the finger chase task, bilaterally."
A molecularly confirmed BNS case directly documents dysdiadochokinesia.
Decreased circulating follicle stimulating hormone concentration HP:0030341 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Decreased circulating follicle stimulating hormone concentration (HP:0030341). HP:0030341 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29749493 SUPPORT Human Clinical
"As illustrated in Table I, the luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of the proband were below normal, whereas the levels of adrenocorticotropic hormone, cortisol and thyroid hormones were in the normal range."
The molecularly confirmed Chinese case directly documents reduced FSH.
Decreased circulating luteinizing hormone level HP:0030344 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Decreased circulating luteinizing hormone level (HP:0030344). HP:0030344 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29749493 SUPPORT Human Clinical
"As illustrated in Table I, the luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of the proband were below normal, whereas the levels of adrenocorticotropic hormone, cortisol and thyroid hormones were in the normal range."
The molecularly confirmed Chinese case directly documents reduced LH.
Decreased serum testosterone concentration HP:0040171 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Decreased serum testosterone concentration (HP:0040171). HP:0040171 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29749493 SUPPORT Human Clinical
"As illustrated in Table I, the luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of the proband were below normal, whereas the levels of adrenocorticotropic hormone, cortisol and thyroid hormones were in the normal range."
The molecularly confirmed Chinese case directly documents low serum testosterone.
Anterior hypopituitarism HP:0000830 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Anterior hypopituitarism (HP:0000830). HP:0000830 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"The hypogonadotropic hypogonadism occurs either in isolation or as part of anterior hypopituitarism (growth hormone, thyroid hormone, or gonadotropin deficiencies)."
GeneReviews documents that anterior hypopituitarism can accompany the hypogonadotropic hypogonadism in PNPLA6 disorders.
Hypothyroidism Pituitary hypothyroidism HP:0008245 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Pituitary hypothyroidism (HP:0008245). HP:0008245 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"The hypogonadotropic hypogonadism occurs either in isolation or as part of anterior hypopituitarism (growth hormone, thyroid hormone, or gonadotropin deficiencies)."
GeneReviews identifies thyroid hormone deficiency as part of anterior hypopituitarism in PNPLA6 disorders.
Reduced pituitary size on MRI
The source reports only reduced pituitary size on MRI in one case; it does not establish an anterior-pituitary localization or developmental hypoplasia, so no HPO term or frequency band is asserted.
Show evidence (1 reference)
PMID:29749493 SUPPORT Human Clinical
"MRI illustrated a reduction in the size the pituitary, the expansion of the right lateral side, and a reduction in the branches of the right middle cerebral artery (Fig. 1C and D)."
The molecularly confirmed Chinese case reports reduced pituitary size on MRI.
Chorioretinal atrophy HP:0000533 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Chorioretinal atrophy (HP:0000533). HP:0000533 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:31135245 SUPPORT Human Clinical
"There were minute islands of apparently spared retina near the foveal center separated from large peripheral islands of better appearing retina by severe pericentral and midperipheral chorioretinal atrophy."
The ophthalmic phenotype paper directly documents chorioretinal atrophy in molecularly confirmed BNS.
Peripheral axonal neuropathy FREQUENT HP:0003477 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Peripheral axonal neuropathy (HP:0003477). HP:0003477 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35069422 SUPPORT Human Clinical
"Additional clinical features included hypogonadotropic hypogonadism (5/8), growth hormone deficiency (2/8), peripheral axonal neuropathy (4/8), cognitive impairment (3/8), chorioretinal dystrophy (2/8)"
Peripheral axonal neuropathy was present in 4/8 PNPLA6 patients in this cohort.
Hyporeflexia HP:0001265 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hyporeflexia (HP:0001265). HP:0001265 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29749493 SUPPORT Human Clinical
"However, the proband presented with subtle defect in the finger-naseversch and alternate motion tests. In addition, the proband exhibited cavus and a reduced tendon reflex."
This molecularly confirmed case directly documents reduced tendon reflexes.
Scanning speech HP:0002168 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Scanning speech (HP:0002168). HP:0002168 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25267340 SUPPORT Human Clinical
"She had a scanning quality to her speech, with mild labial and lingual dysarthria."
A molecularly confirmed BNS case directly supports scanning speech.
🧬

Genetic Associations

1
PNPLA6 (Loss of function mutation)
Gene: PNPLA6 hgnc:16268 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is PNPLA6 (hgnc:16268). hgnc:16268 is a gene from the HUGO Gene Nomenclature Committee.
Show evidence (3 references)
PMID:35198007 SUPPORT Human Clinical
"Boucher-Neuhäuser syndrome (BNS, MIM 215470) is a rare autosomal recessive syndrome caused by mutations in the PNPLA6 gene."
Directly identifies PNPLA6 as the causal gene for BNS.
PMID:25267340 SUPPORT Human Clinical
"both mutations (one novel and one known) fell in the phospholipase esterase domain, where most pathogenic mutations seem to cluster"
Documents that pathogenic PNPLA6 variants in BNS cluster in the phospholipase esterase (catalytic) domain.
PMID:35069422 SUPPORT Human Clinical
"A wide spectrum of neurodegenerative diseases has been associated with pathogenic variants in the PNPLA6 (patatin-like phospholipase domain-containing protein 6) gene, including spastic paraplegia type 39, Gordon-Holmes, Boucher-Neuhauser, Oliver-Mc Farlane, and Laurence-Moon syndromes."
Establishes BNS as part of the broader allelic PNPLA6 disorder spectrum.
💊

Medical Actions

3
Hormone replacement therapy
Action: Hormone replacement therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Hormone replacement therapy (NCIT:C15599). NCIT:C15599 is a clinical intervention from the NCI Thesaurus. Ontology label: Hormone Replacement Therapy NCIT:C15599
Management is symptomatic. Hormone replacement therapy is given for the endocrine deficiencies: at the expected time of puberty for hypogonadotropic hypogonadism, during childhood/adolescence for growth hormone deficiency, and as soon as identified for hypothyroidism.
Mechanism Target:
RESTORES Hypothalamic-pituitary endocrine dysfunction — Replaces deficient sex-hormone signaling at the expected time of puberty.
RESTORES Anterior pituitary dysfunction — Replaces deficient growth or thyroid hormone when indicated.
Target Phenotypes: Hypogonadotropic hypogonadism HP:0000044 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Hypogonadotropic hypogonadism (HP:0000044). HP:0000044 is a phenotype from the Human Phenotype Ontology. Secondary growth hormone deficiency HP:0008240 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Secondary growth hormone deficiency (HP:0008240). HP:0008240 is a phenotype from the Human Phenotype Ontology. Pituitary hypothyroidism HP:0008245 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Pituitary hypothyroidism (HP:0008245). HP:0008245 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"Hypogonadotropic hypogonadism. Hormone replacement therapy at the expected time of puberty."
GeneReviews recommends hormone replacement therapy for the hypogonadotropic hypogonadism of PNPLA6 disorders.
Supportive and rehabilitative care
Action: supportive careNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is supportive care (NCIT:C15747). NCIT:C15747 is a clinical intervention from the NCI Thesaurus. Ontology label: Supportive Care NCIT:C15747
Symptomatic, individually tailored multidisciplinary care: continuous training of speech/swallowing, fine-motor skills, gait, and balance for ataxia; physical therapy, assistive walking devices, and antispasticity measures for spasticity; and low-vision aids and visual rehabilitation for chorioretinal dystrophy. Patients should avoid alcohol, obesity, a sedentary lifestyle, and medications/chemicals that exacerbate neuropathy.
Show evidence (2 references)
PMID:25299038 SUPPORT Human Clinical
"Management is symptomatic and individually tailored. Ataxia. Continuous training of speech and swallowing, fine-motor skills, gait, and balance."
GeneReviews describes the symptomatic, multidisciplinary supportive management of PNPLA6 disorders.
PMID:25299038 SUPPORT Human Clinical
"Agents/circumstances to avoid: Alcohol; obesity; inactive, sedentary lifestyle; exposure to medications or chemicals that exacerbate neuropathy."
GeneReviews lists agents/circumstances to avoid, captured here as part of supportive management guidance.
Genetic counseling
Action: Genetic CounselingNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Genetic Counseling (NCIT:C15240). NCIT:C15240 is a clinical intervention from the NCI Thesaurus. NCIT:C15240
Genetic counseling is recommended given autosomal recessive inheritance. Once the familial PNPLA6 variants are known, carrier testing for at-risk relatives, prenatal testing, and preimplantation genetic testing are possible.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"Once the PNPLA6 pathogenic variants in the family have been identified, carrier testing for at-risk relatives, prenatal testing for a pregnancy at increased risk, and preimplantation genetic testing are possible."
GeneReviews describes the genetic-counseling options available for PNPLA6 disorders.
🔬

Diagnosis

1
Molecular genetic testing
Diagnosis is established in a proband with suggestive findings (cerebellar ataxia, chorioretinal dystrophy, hypogonadotropic hypogonadism) by identifying biallelic PNPLA6 pathogenic variants, typically via whole-exome sequencing with Sanger segregation. Functional NTE esterase-activity assays are an emerging adjunct for variant classification and phenotype prediction.
Show evidence (2 references)
PMID:25299038 SUPPORT Human Clinical
"The diagnosis of a PNPLA6 disorder is established in a proband with suggestive findings and biallelic PNPLA6 pathogenic variants identified on homologous alleles by molecular genetic testing."
GeneReviews describes the molecular diagnostic approach for PNPLA6 disorders, including BNS.
PMID:35198007 SUPPORT Human Clinical
"Gene sequencing is currently the primary diagnostic method."
Confirms gene sequencing as the primary diagnostic modality for BNS.
📈

Progression

2
Age-dependent presentation
Presenting features differ by age of onset: chorioretinal dystrophy is most frequent with early onset, hypogonadotropic hypogonadism with juvenile onset, and cerebellar ataxia with adult onset.
Show evidence (1 reference)
PMID:35069422 SUPPORT Human Clinical
"chorioretinal dystrophy was the most frequent presenting symptom in early onset patients, hypogonadotropic hypogonadism in juvenile onset cases, and cerebellar ataxia in adult patients"
The cohort describes age-dependent presenting phenotypes.
Slowly progressive cerebellar syndrome
Duration: 15 years
Ambulation was retained despite the slow progression of cerebellar symptoms.
Show evidence (1 reference)
PMID:35069422 SUPPORT Human Clinical
"Progression of cerebellar symptoms was slow in all patients, who retained ambulation even after a mean disease duration of 15 years."
The PNPLA6 cohort supports a slowly progressive cerebellar course with long preservation of ambulation.
{ }

Source YAML

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name: Boucher-Neuhauser Syndrome
creation_date: "2026-06-04T12:00:00Z"
category: Mendelian
synonyms:
- BNHS
- Boucher-Neuhäuser syndrome
- Spinocerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy
- Ataxia-hypogonadism-choroidal dystrophy syndrome
description: >-
  Boucher-Neuhauser syndrome (BNS) is a rare autosomal recessive
  neurodegenerative disorder caused by biallelic pathogenic variants in PNPLA6,
  which encodes neuropathy target esterase (NTE). It is classically defined by
  the triad of cerebellar ataxia, hypogonadotropic hypogonadism, and
  chorioretinal dystrophy, and is now recognized as one cluster on a continuous
  PNPLA6-disorder spectrum that also includes Gordon Holmes syndrome,
  Oliver-McFarlane syndrome, Laurence-Moon syndrome, and spastic paraplegia
  type 39. NTE is an endoplasmic-reticulum-associated phospholipase/esterase
  required for phospholipid (phosphatidylcholine/lysophospholipid) homeostasis;
  loss of NTE activity causes degeneration of cerebellar, retinal, and
  hypothalamic-pituitary neurons. Residual NTE activity correlates inversely
  with the presence of retinopathy and endocrinopathy.
disease_term:
  preferred_term: Boucher-Neuhauser syndrome
  term:
    id: MONDO:0008980
    label: ataxia-hypogonadism-choroidal dystrophy syndrome
parents:
- Hereditary Ataxia
- Congenital Hypogonadotropic Hypogonadism
references:
- reference: PMID:25299038
  title: "PNPLA6 Disorders."
  tags:
  - GeneReviews
- reference: PMID:24355708
  title: PNPLA6 mutations cause Boucher-Neuhauser and Gordon Holmes syndromes as part of a broad neurodegenerative spectrum.
- reference: PMID:25267340
  title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
- reference: PMID:29749493
  title: "A novel PNPLA6 compound heterozygous mutation identified in a Chinese patient with Boucher‑Neuhäuser syndrome."
- reference: PMID:31135245
  title: "Detailed retinal phenotype of Boucher-Neuhäuser syndrome associated with mutations in PNPLA6 mimicking choroideremia."
- reference: PMID:35069422
  title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
- reference: PMID:35198007
  title: "Identification of Novel Compound Heterozygous Variants of the PNPLA6 Gene in Boucher-Neuhäuser Syndrome."
- reference: PMID:35448471
  title: "PNPLA6/NTE, an Evolutionary Conserved Phospholipase Linked to a Group of Complex Human Diseases."
- reference: PMID:37732399
  title: "PNPLA6 disorders: what's in a name?"
- reference: PMID:38683245
  title: "Two case reports of a novel missense mutation in the PNPLA6 gene in two siblings with chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia."
- reference: PMID:38735647
  title: "Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders."
inheritance:
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    BNS is caused by biallelic (homozygous or compound heterozygous) pathogenic
    variants in PNPLA6 and is inherited in an autosomal recessive manner.
  evidence:
  - reference: PMID:38683245
    reference_title: "Two case reports of a novel missense mutation in the PNPLA6 gene in two siblings with chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Boucher Neuhäuser Syndrome (BNS) is a rare disease with autosomal recessive inheritance defined by the classical triad; early-onset ataxia, hypogonadism and chorioretinal dystrophy.
    explanation: >-
      Directly states the autosomal recessive inheritance pattern and the
      defining clinical triad.
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PNPLA6 disorders are inherited in an autosomal recessive manner.
    explanation: >-
      GeneReviews confirms autosomal recessive inheritance for the PNPLA6
      disorder spectrum, which includes BNS.
pathophysiology:
- name: Loss of neuropathy target esterase (NTE) activity
  description: >-
    PNPLA6 encodes neuropathy target esterase (NTE), a patatin-like serine
    hydrolase on the cytoplasmic face of the endoplasmic reticulum with
    phospholipase/lysophospholipase activity. NTE deacylates glycerophospholipids
    and is central to phosphatidylcholine homeostasis. Biallelic pathogenic
    PNPLA6 variants, which cluster in the C-terminal phospholipase/esterase
    (patatin-like) domain, reduce NTE esterase activity, the principal
    loss-of-function mechanism underlying BNS.
  genes:
  - preferred_term: PNPLA6
    term:
      id: hgnc:16268
      label: PNPLA6
  biological_processes:
  - preferred_term: phospholipid metabolic process
    term:
      id: GO:0006644
      label: phospholipid metabolic process
    modifier: DECREASED
  - preferred_term: phosphatidylcholine metabolic process
    term:
      id: GO:0046470
      label: phosphatidylcholine metabolic process
    modifier: ABNORMAL
  molecular_functions:
  - preferred_term: glycerophospholipase (NTE esterase) activity
    term:
      id: GO:0004620
      label: glycerophospholipase activity
    modifier: DECREASED
  - preferred_term: carboxylic ester hydrolase activity
    term:
      id: GO:0052689
      label: carboxylic ester hydrolase activity
    modifier: DECREASED
  cellular_components:
  - preferred_term: endoplasmic reticulum membrane
    term:
      id: GO:0005789
      label: endoplasmic reticulum membrane
  evidence:
  - reference: PMID:37732399
    reference_title: "PNPLA6 disorders: what's in a name?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PNPLA6 encodes NTE, an enzyme involved in maintaining phospholipid homeostasis and trafficking in the nervous system.
    explanation: >-
      Establishes NTE's role in phospholipid homeostasis whose disruption is the
      molecular basis of BNS.
  - reference: PMID:38735647
    reference_title: "Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Measuring esterase activity of 46 disease-associated and 20 common variants observed across PNPLA6-associated clinical diagnoses unambiguously reclassified 36 variants as pathogenic and 10 variants as likely pathogenic
    explanation: >-
      Demonstrates that disease-associated PNPLA6 variants reduce NTE esterase
      activity, supporting loss of enzymatic function as the mechanism.
  downstream:
  - target: NTE-activity-dependent neurodegeneration of vulnerable tissues
    description: Reduced PNPLA6/NTE esterase activity produces the tissue-vulnerability phenotype continuum across PNPLA6 disorders.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:38735647
      reference_title: "Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Estimating the overall NTE activity of affected individuals revealed a striking inverse relationship between NTE activity and the presence of retinopathy and endocrinopathy.
      explanation: Human genotype-function data link lower NTE activity to retinal and endocrine phenotypes.
- name: NTE-activity-dependent neurodegeneration of vulnerable tissues
  description: >-
    Reduced NTE activity disrupts phospholipid remodeling at ER membranes,
    rendering specific neuronal and supporting cell populations vulnerable to
    age-dependent degeneration: cerebellar Purkinje-cell circuits (ataxia),
    retinal photoreceptors and retinal pigment epithelium (chorioretinal
    dystrophy), and hypothalamic-pituitary neurons (hypogonadotropic
    hypogonadism / anterior hypopituitarism). Overall NTE activity is inversely
    related to the presence of retinopathy and endocrinopathy, defining a
    genotype:activity:phenotype continuum across PNPLA6 disorders. An allelic
    mouse series recapitulates an NTE activity threshold for retinal
    degeneration, with complete loss being embryonic lethal.
  cell_types:
  - preferred_term: cerebellar Purkinje cell
    term:
      id: CL:0000121
      label: Purkinje cell
  - preferred_term: retinal photoreceptor cell
    term:
      id: CL:0000210
      label: photoreceptor cell
  - preferred_term: retinal pigment epithelial cell
    term:
      id: CL:0002586
      label: retinal pigment epithelial cell
  biological_processes:
  - preferred_term: neuron apoptotic process
    term:
      id: GO:0051402
      label: neuron apoptotic process
    modifier: INCREASED
  evidence:
  - reference: PMID:38735647
    reference_title: "Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Estimating the overall NTE activity of affected individuals revealed a striking inverse relationship between NTE activity and the presence of retinopathy and endocrinopathy.
    explanation: >-
      Links reduced NTE activity quantitatively to the retinal and endocrine
      manifestations of the PNPLA6 spectrum that includes BNS.
  - reference: PMID:38735647
    reference_title: "Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      This phenomenon was recaptured in vivo in an allelic mouse series, where a similar NTE threshold for retinopathy exists.
    explanation: >-
      An allelic mouse series recapitulates the NTE-activity threshold for
      retinal degeneration, supporting the causal chain in vivo.
  - reference: PMID:35448471
    reference_title: "PNPLA6/NTE, an Evolutionary Conserved Phospholipase Linked to a Group of Complex Human Diseases."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      A conditional knockout of PNPLA6/NTE in the mouse brain results in age-related neurodegeneration, whereas a complete knockout causes lethality during embryogenesis due to defects in the development of the placenta.
    explanation: >-
      Mouse models show that NTE loss causes age-related neurodegeneration and
      that complete loss is embryonic lethal, consistent with the human
      activity-threshold model.
  downstream:
  - target: Cerebellar neuronal dysfunction
    description: Cerebellar neuronal vulnerability produces a cerebellar dysfunction cascade.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25267340
      reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy.
      explanation: The defining Boucher-Neuhauser triad includes cerebellar ataxia.
  - target: Cerebellar atrophy
    description: Cerebellar neurodegeneration is visible as cerebellar atrophy on MRI.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:35069422
      reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Brain MRI showed cerebellar atrophy in 6/8 patients, more pronounced in superior and dorsal vermis lobules (I to VII).
      explanation: PNPLA6 cohort data support cerebellar atrophy as a structural outcome.
  - target: Hypothalamic-pituitary endocrine dysfunction
    description: Hypothalamic-pituitary vulnerability produces the endocrine phenotype cascade.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25267340
      reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy.
      explanation: The defining Boucher-Neuhauser triad includes hypogonadotropic hypogonadism.
  - target: Anterior pituitary dysfunction
    description: Endocrine involvement can extend to an anterior-pituitary dysfunction cascade.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25299038
      reference_title: "PNPLA6 Disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The hypogonadotropic hypogonadism occurs either in isolation or as part of anterior hypopituitarism (growth hormone, thyroid hormone, or gonadotropin deficiencies).
      explanation: GeneReviews supports anterior hypopituitarism as part of the PNPLA6 endocrine phenotype spectrum.
  - target: Chorioretinal degeneration
    description: Retinal vulnerability produces a chorioretinal degeneration cascade.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25267340
      reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy.
      explanation: The defining Boucher-Neuhauser triad includes chorioretinal dystrophy.
  - target: Peripheral axonal degeneration
    description: PNPLA6 neurodegenerative involvement can extend to peripheral axonal degeneration.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:35069422
      reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Additional clinical features included hypogonadotropic hypogonadism (5/8), growth hormone deficiency (2/8), peripheral axonal neuropathy (4/8), cognitive impairment (3/8), chorioretinal dystrophy (2/8)
      explanation: Cohort data support peripheral axonal neuropathy as a PNPLA6-spectrum feature.
  - target: Spasticity
    description: Upper-motor-neuron involvement in PNPLA6 disorders can manifest as spasticity.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25299038
      reference_title: "PNPLA6 Disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        upper motor neuron involvement manifesting as spasticity and/or brisk reflexes
      explanation: GeneReviews supports spasticity as an upper-motor-neuron manifestation.
  - target: Cognitive impairment
    description: CNS involvement in the PNPLA6 spectrum includes cognitive impairment in a subset of patients.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25299038
      reference_title: "PNPLA6 Disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        impaired cognitive functioning (learning disabilities in children; deficits in attention, visuospatial abilities, and recall in adults)
      explanation: GeneReviews supports cognitive impairment as a PNPLA6-spectrum phenotype.
  - target: Nystagmus
    description: Cerebellar and ocular involvement can produce nystagmus.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25267340
      reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        She had hypometric vertical and horizontal saccades, saccadic smooth pursuit, gaze-evoked nystagmus and poor visual suppression of vestibular ocular reflexes.
      explanation: A molecularly confirmed case supports nystagmus as an oculomotor output.
- name: Cerebellar neuronal dysfunction
  biological_scale: CELLULAR
  description: >-
    PNPLA6-related cerebellar neuronal vulnerability produces cerebellar motor
    dysfunction with structural atrophy and clinical ataxia.
  downstream:
  - target: Cerebellar ataxia
    description: Cerebellar neuronal dysfunction manifests as cerebellar ataxia.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Gait ataxia
    description: Cerebellar motor dysfunction produces gait ataxia.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Dysdiadochokinesia
    description: Cerebellar dysfunction impairs rapid alternating movements.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Scanning speech
    description: Cerebellar dysarthria can produce a scanning quality to speech.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- name: Hypothalamic-pituitary endocrine dysfunction
  biological_scale: ORGANISM
  description: >-
    Central endocrine dysfunction produces hypogonadotropic hypogonadism and
    its measured gonadotropin and sex-hormone consequences.
  downstream:
  - target: Hypogonadotropic hypogonadism
    description: Central endocrine dysfunction manifests as hypogonadotropic hypogonadism.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Decreased circulating follicle stimulating hormone concentration
    description: Central gonadotropin deficiency can lower circulating FSH.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Decreased circulating luteinizing hormone level
    description: Central gonadotropin deficiency can lower circulating LH.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Decreased serum testosterone concentration
    description: Reduced gonadotropin signaling can lower testosterone in affected males.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Primary amenorrhea
    description: Gonadotropin deficiency can present as primary amenorrhea in affected females.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- name: Anterior pituitary dysfunction
  biological_scale: ORGANISM
  description: >-
    Anterior pituitary dysfunction can include growth hormone, thyroid hormone,
    and gonadotropin deficiencies.
  downstream:
  - target: Anterior hypopituitarism
    description: The clinical endocrine syndrome is anterior hypopituitarism.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Growth hormone deficiency
    description: Anterior pituitary dysfunction can include growth hormone deficiency.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Hypothyroidism
    description: Anterior pituitary dysfunction can include thyroid hormone deficiency.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Reduced pituitary size on MRI
    description: Pituitary dysfunction can be accompanied by reduced pituitary size on MRI.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Chorioretinal degeneration
  biological_scale: TISSUE
  description: >-
    Retinal degeneration produces chorioretinal dystrophy, retinal atrophy, and
    visual impairment.
  downstream:
  - target: Chorioretinal dystrophy
    description: Chorioretinal degeneration manifests as chorioretinal dystrophy.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Chorioretinal atrophy
    description: Progressive chorioretinal degeneration produces chorioretinal atrophy.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Retinal pigment epithelial atrophy
    description: Progressive retinal degeneration includes RPE atrophy.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Visual impairment
    description: Chorioretinal degeneration causes visual impairment.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- name: Peripheral axonal degeneration
  biological_scale: CELLULAR
  description: >-
    PNPLA6-related peripheral axonal degeneration produces neuropathy and
    reduced tendon reflexes.
  downstream:
  - target: Peripheral axonal neuropathy
    description: Peripheral axonal degeneration manifests as axonal neuropathy.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Hyporeflexia
    description: Peripheral axonal neuropathy can manifest as reduced tendon reflexes.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
phenotypes:
- name: Cerebellar ataxia
  category: Phenotypic
  description: >-
    Cerebellar ataxia/cerebellar degeneration is a core feature, with onset
    ranging from childhood to adulthood and typically slow progression; brain
    MRI commonly shows cerebellar (often superior vermian) atrophy.
  phenotype_term:
    preferred_term: Cerebellar ataxia
    term:
      id: HP:0001251
      label: Ataxia
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy.
    explanation: >-
      Identifies cerebellar ataxia as a defining component of the BNS triad.
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Cerebellar ataxia was observed in seven patients and spastic paraplegia in one patient.
    explanation: >-
      In a cohort of eight biallelic PNPLA6 cases, cerebellar ataxia was present
      in 7/8, supporting it as a very frequent feature.
- name: Gait ataxia
  category: Phenotypic
  description: >-
    The cerebellar syndrome in BNS typically becomes clinically apparent as a
    progressive gait ataxia, although age of onset can range from childhood to
    late adulthood.
  phenotype_term:
    preferred_term: Gait ataxia
    term:
      id: HP:0002066
      label: Gait ataxia
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Gait ataxia in Boucher-Neuhäuser usually manifests before early adulthood, although onset in the third or fourth decade has also been reported.
    explanation: >-
      This molecularly confirmed case report identifies gait ataxia as the usual
      clinical manifestation of BNS cerebellar disease.
- name: Dysdiadochokinesia
  category: Phenotypic
  description: >-
    Cerebellar dysfunction frequently impairs rapid alternating movements in
    the limbs.
  phenotype_term:
    preferred_term: Dysdiadochokinesia
    term:
      id: HP:0002075
      label: Dysdiadochokinesis
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      She had dysdiadochokinesia in her arms and legs, dysmetria on heel-to-shin but not on finger-to-nose, and significant overshoot on the finger chase task, bilaterally.
    explanation: >-
      A molecularly confirmed BNS case directly documents dysdiadochokinesia.
- name: Cerebellar atrophy
  category: Phenotypic
  description: >-
    Brain MRI shows cerebellar atrophy, most pronounced in the superior and
    dorsal vermis.
  phenotype_term:
    preferred_term: Cerebellar atrophy
    term:
      id: HP:0001272
      label: Cerebellar atrophy
  frequency: FREQUENT
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Brain MRI showed cerebellar atrophy in 6/8 patients, more pronounced in superior and dorsal vermis lobules (I to VII).
    explanation: >-
      Documents cerebellar atrophy with characteristic superior/dorsal vermian
      predominance in PNPLA6 patients.
  - reference: PMID:31135245
    reference_title: "Detailed retinal phenotype of Boucher-Neuhäuser syndrome associated with mutations in PNPLA6 mimicking choroideremia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Hypogonadotropic hypogonadism and cerebellar vermis hypoplasia by MRI confirmed a diagnosis of Boucher-Neuhäuser syndrome.
    explanation: >-
      Cerebellar vermis involvement on MRI contributed to the BNS diagnosis in a
      molecularly confirmed case.
- name: Hypogonadotropic hypogonadism
  category: Phenotypic
  description: >-
    Hypogonadotropic hypogonadism presents as delayed puberty and lack of
    secondary sexual characteristics, with low gonadotropins (LH/FSH). It may
    occur in isolation or as part of broader anterior hypopituitarism.
  phenotype_term:
    preferred_term: Hypogonadotropic hypogonadism
    term:
      id: HP:0000044
      label: Hypogonadotropic hypogonadism
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy.
    explanation: >-
      Identifies hypogonadotropic hypogonadism as a defining component of the BNS
      triad.
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      hypogonadotropic hypogonadism (delayed puberty and lack of secondary sex characteristics)
    explanation: >-
      GeneReviews describes the clinical presentation of the hypogonadotropic
      hypogonadism characteristic of BNS.
- name: Decreased circulating follicle stimulating hormone concentration
  category: Phenotypic
  description: >-
    BNS endocrine dysfunction can specifically lower circulating follicle
    stimulating hormone concentration.
  phenotype_term:
    preferred_term: Decreased circulating follicle stimulating hormone concentration
    term:
      id: HP:0030341
      label: Decreased circulating follicle stimulating hormone concentration
  evidence:
  - reference: PMID:29749493
    reference_title: "A novel PNPLA6 compound heterozygous mutation identified in a Chinese patient with Boucher‑Neuhäuser syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      As illustrated in Table I, the luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of the proband were below normal, whereas the levels of adrenocorticotropic hormone, cortisol and thyroid hormones were in the normal range.
    explanation: >-
      The molecularly confirmed Chinese case directly documents reduced FSH.
- name: Decreased circulating luteinizing hormone level
  category: Phenotypic
  description: >-
    BNS endocrine dysfunction can specifically lower circulating luteinizing
    hormone concentration.
  phenotype_term:
    preferred_term: Decreased circulating luteinizing hormone level
    term:
      id: HP:0030344
      label: Decreased circulating luteinizing hormone level
  evidence:
  - reference: PMID:29749493
    reference_title: "A novel PNPLA6 compound heterozygous mutation identified in a Chinese patient with Boucher‑Neuhäuser syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      As illustrated in Table I, the luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of the proband were below normal, whereas the levels of adrenocorticotropic hormone, cortisol and thyroid hormones were in the normal range.
    explanation: >-
      The molecularly confirmed Chinese case directly documents reduced LH.
- name: Decreased serum testosterone concentration
  category: Phenotypic
  description: >-
    Gonadotropic dysfunction in affected males can produce low serum
    testosterone concentration.
  phenotype_term:
    preferred_term: Decreased serum testosterone concentration
    term:
      id: HP:0040171
      label: Decreased serum testosterone concentration
  evidence:
  - reference: PMID:29749493
    reference_title: "A novel PNPLA6 compound heterozygous mutation identified in a Chinese patient with Boucher‑Neuhäuser syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      As illustrated in Table I, the luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of the proband were below normal, whereas the levels of adrenocorticotropic hormone, cortisol and thyroid hormones were in the normal range.
    explanation: >-
      The molecularly confirmed Chinese case directly documents low serum
      testosterone.
- name: Anterior hypopituitarism
  category: Phenotypic
  description: >-
    In a subset of patients, hypogonadotropic hypogonadism occurs as part of
    broader anterior hypopituitarism with additional growth hormone, thyroid
    hormone, or gonadotropin deficiencies.
  phenotype_term:
    preferred_term: Anterior hypopituitarism
    term:
      id: HP:0000830
      label: Anterior hypopituitarism
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The hypogonadotropic hypogonadism occurs either in isolation or as part of anterior hypopituitarism (growth hormone, thyroid hormone, or gonadotropin deficiencies).
    explanation: >-
      GeneReviews documents that anterior hypopituitarism can accompany the
      hypogonadotropic hypogonadism in PNPLA6 disorders.
- name: Growth hormone deficiency
  category: Phenotypic
  description: >-
    Growth hormone deficiency can occur as part of anterior hypopituitarism in
    the PNPLA6 spectrum.
  phenotype_term:
    preferred_term: Secondary growth hormone deficiency
    term:
      id: HP:0008240
      label: Secondary growth hormone deficiency
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Additional clinical features included hypogonadotropic hypogonadism (5/8), growth hormone deficiency (2/8), peripheral axonal neuropathy (4/8), cognitive impairment (3/8), chorioretinal dystrophy (2/8)
    explanation: The PNPLA6 cohort reports growth hormone deficiency in 2/8 patients.
- name: Hypothyroidism
  category: Phenotypic
  description: >-
    Thyroid hormone deficiency can occur as part of anterior hypopituitarism in
    the PNPLA6 spectrum.
  phenotype_term:
    preferred_term: Pituitary hypothyroidism
    term:
      id: HP:0008245
      label: Pituitary hypothyroidism
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The hypogonadotropic hypogonadism occurs either in isolation or as part of anterior hypopituitarism (growth hormone, thyroid hormone, or gonadotropin deficiencies).
    explanation: GeneReviews identifies thyroid hormone deficiency as part of anterior hypopituitarism in PNPLA6 disorders.
- name: Reduced pituitary size on MRI
  category: Phenotypic
  description: >-
    Some patients show reduced pituitary size on MRI as part of the endocrine
    involvement.
  notes: >-
    The source reports only reduced pituitary size on MRI in one case; it does
    not establish an anterior-pituitary localization or developmental
    hypoplasia, so no HPO term or frequency band is asserted.
  evidence:
  - reference: PMID:29749493
    reference_title: "A novel PNPLA6 compound heterozygous mutation identified in a Chinese patient with Boucher‑Neuhäuser syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      MRI illustrated a reduction in the size the pituitary, the expansion of the right lateral side, and a reduction in the branches of the right middle cerebral artery (Fig. 1C and D).
    explanation: >-
      The molecularly confirmed Chinese case reports reduced pituitary size on MRI.
- name: Primary amenorrhea
  category: Phenotypic
  description: >-
    In affected females, gonadotropic failure may first present as primary
    amenorrhea before progressive neurologic manifestations appear.
  phenotype_term:
    preferred_term: Primary amenorrhea
    term:
      id: HP:0000786
      label: Primary amenorrhea
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This 59-year-old woman, born to non-consanguineous parents from Spain and Italy, had normal development until adolescence, when it was noted that she had primary amenorrhea.
    explanation: >-
      A molecularly confirmed BNS case shows primary amenorrhea as an early
      endocrine presentation.
- name: Chorioretinal dystrophy
  category: Phenotypic
  description: >-
    Chorioretinal dystrophy with progressive retinal pigment epithelium and
    choriocapillaris atrophy; onset is widely variable and the presentation can
    closely mimic choroideremia, sometimes progressing to severe visual loss or
    blindness.
  phenotype_term:
    preferred_term: Chorioretinal dystrophy
    term:
      id: HP:0001135
      label: Chorioretinal dystrophy
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy.
    explanation: >-
      Identifies chorioretinal dystrophy as a defining component of the BNS triad.
  - reference: PMID:37732399
    reference_title: "PNPLA6 disorders: what's in a name?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Retinal disease presents with a unique chorioretinal dystrophy that is phenotypically similar to choroideremia and Leber congenital amaurosis.
    explanation: >-
      Characterizes the chorioretinal dystrophy and its choroideremia-like
      appearance in PNPLA6 disorders.
- name: Chorioretinal atrophy
  category: Phenotypic
  description: >-
    Advanced retinal degeneration in BNS may produce severe pericentral and
    midperipheral chorioretinal atrophy.
  phenotype_term:
    preferred_term: Chorioretinal atrophy
    term:
      id: HP:0000533
      label: Chorioretinal atrophy
  evidence:
  - reference: PMID:31135245
    reference_title: "Detailed retinal phenotype of Boucher-Neuhäuser syndrome associated with mutations in PNPLA6 mimicking choroideremia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      There were minute islands of apparently spared retina near the foveal center separated from large peripheral islands of better appearing retina by severe pericentral and midperipheral chorioretinal atrophy.
    explanation: >-
      The ophthalmic phenotype paper directly documents chorioretinal atrophy
      in molecularly confirmed BNS.
- name: Retinal pigment epithelial atrophy
  category: Phenotypic
  description: >-
    Progressive retinal degeneration in BNS includes retinal pigment
    epithelium and choriocapillaris atrophy.
  phenotype_term:
    preferred_term: Retinal pigment epithelial atrophy
    term:
      id: HP:0007722
      label: Retinal pigment epithelial atrophy
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The ocular changes noted in B–N are distinctive in their pattern of progressive RPE and choriocapillaris atrophy, with macular changes in the posterior pole and mid-periphery of each eye.
    explanation: >-
      The ocular description directly supports retinal pigment epithelial
      atrophy as part of the BNS retinal phenotype.
- name: Visual impairment
  category: Phenotypic
  description: >-
    Progressive chorioretinal degeneration leads to variable visual impairment,
    which may progress to blindness.
  phenotype_term:
    preferred_term: Visual impairment
    term:
      id: HP:0000505
      label: Visual impairment
  evidence:
  - reference: PMID:38735647
    reference_title: "Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Biallelic pathogenic variants in the PNPLA6 gene cause a broad spectrum of disorders leading to gait disturbance, visual impairment, anterior hypopituitarism and hair anomalies.
    explanation: >-
      Lists visual impairment among the cardinal manifestations of PNPLA6
      disorders, including BNS.
- name: Peripheral axonal neuropathy
  category: Phenotypic
  description: >-
    A peripheral neuropathy of axonal type (reduced distal reflexes, diminished
    vibratory sensation, and/or distal muscle wasting) is a common but less
    frequent feature; it may be subclinical and detected only on EMG/NCS.
  phenotype_term:
    preferred_term: Peripheral axonal neuropathy
    term:
      id: HP:0003477
      label: Peripheral axonal neuropathy
  frequency: FREQUENT
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Additional clinical features included hypogonadotropic hypogonadism (5/8), growth hormone deficiency (2/8), peripheral axonal neuropathy (4/8), cognitive impairment (3/8), chorioretinal dystrophy (2/8)
    explanation: >-
      Peripheral axonal neuropathy was present in 4/8 PNPLA6 patients in this
      cohort.
- name: Hyporeflexia
  category: Phenotypic
  description: >-
    Peripheral nerve involvement may be clinically evident as reduced tendon
    reflexes.
  phenotype_term:
    preferred_term: Hyporeflexia
    term:
      id: HP:0001265
      label: Hyporeflexia
  evidence:
  - reference: PMID:29749493
    reference_title: "A novel PNPLA6 compound heterozygous mutation identified in a Chinese patient with Boucher‑Neuhäuser syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      However, the proband presented with subtle defect in the finger-naseversch and alternate motion tests. In addition, the proband exhibited cavus and a reduced tendon reflex.
    explanation: >-
      This molecularly confirmed case directly documents reduced tendon reflexes.
- name: Spasticity
  category: Phenotypic
  description: >-
    Upper motor neuron involvement manifesting as spasticity and/or brisk
    reflexes occurs along the PNPLA6 phenotypic continuum.
  phenotype_term:
    preferred_term: Spasticity
    term:
      id: HP:0001257
      label: Spasticity
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      upper motor neuron involvement manifesting as spasticity and/or brisk reflexes
    explanation: >-
      GeneReviews lists spasticity from upper motor neuron involvement among the
      features of the PNPLA6 spectrum.
- name: Cognitive impairment
  category: Phenotypic
  description: >-
    Impaired cognitive functioning (learning disabilities in children; deficits
    in attention, visuospatial abilities, and recall in adults) occurs in a
    subset of patients.
  phenotype_term:
    preferred_term: Cognitive impairment
    term:
      id: HP:0100543
      label: Cognitive impairment
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      impaired cognitive functioning (learning disabilities in children; deficits in attention, visuospatial abilities, and recall in adults)
    explanation: >-
      GeneReviews documents cognitive impairment as a less frequent feature of
      PNPLA6 disorders.
- name: Scanning speech
  category: Phenotypic
  description: >-
    Cerebellar dysarthria can produce a scanning quality to speech.
  phenotype_term:
    preferred_term: Scanning speech
    term:
      id: HP:0002168
      label: Scanning speech
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      She had a scanning quality to her speech, with mild labial and lingual dysarthria.
    explanation: >-
      A molecularly confirmed BNS case directly supports scanning speech.
- name: Nystagmus
  category: Phenotypic
  description: >-
    Oculomotor abnormalities including gaze-evoked nystagmus and saccadic
    pursuit have been reported.
  phenotype_term:
    preferred_term: Nystagmus
    term:
      id: HP:0000639
      label: Nystagmus
  evidence:
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      She had hypometric vertical and horizontal saccades, saccadic smooth pursuit, gaze-evoked nystagmus and poor visual suppression of vestibular ocular reflexes.
    explanation: >-
      Documents gaze-evoked nystagmus and saccadic pursuit abnormalities in a
      molecularly confirmed BNS case.
progression:
- phase: Age-dependent presentation
  notes: >-
    Presenting features differ by age of onset: chorioretinal dystrophy is most
    frequent with early onset, hypogonadotropic hypogonadism with juvenile
    onset, and cerebellar ataxia with adult onset.
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      chorioretinal dystrophy was the most frequent presenting symptom in early onset patients, hypogonadotropic hypogonadism in juvenile onset cases, and cerebellar ataxia in adult patients
    explanation: The cohort describes age-dependent presenting phenotypes.
- phase: Slowly progressive cerebellar syndrome
  duration: 15 years
  notes: >-
    Ambulation was retained despite the slow progression of cerebellar symptoms.
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Progression of cerebellar symptoms was slow in all patients, who retained ambulation even after a mean disease duration of 15 years.
    explanation: >-
      The PNPLA6 cohort supports a slowly progressive cerebellar course with
      long preservation of ambulation.
discussions:
- discussion_id: bns_pnpla6_spectrum_boundaries
  prompt: >-
    Should Boucher-Neuhauser syndrome be curated primarily as a discrete triad
    syndrome or as one phenotypic cluster within a broader PNPLA6
    neurodegenerative spectrum?
  kind: INTERPRETATION
  status: OPEN
  attaches_to:
  - disease#Boucher-Neuhauser Syndrome
  - genetic#PNPLA6
  rationale: >-
    The triad remains clinically useful, but PNPLA6 case series increasingly
    show overlapping retinal, endocrine, cerebellar, pyramidal, and peripheral
    nerve features across named syndromes. Overcommitting to a rigid syndrome
    boundary would understate this allelic continuum.
  evidence:
  - reference: PMID:24355708
    reference_title: PNPLA6 mutations cause Boucher-Neuhauser and Gordon Holmes syndromes as part of a broad neurodegenerative spectrum.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Boucher-Neuhäuser and Gordon Holmes syndromes in fact represent phenotypic clusters on a spectrum of neurodegenerative diseases caused by mutations in PNPLA6.
    explanation: The 2014 spectrum paper states the disease-boundary issue directly.
genetic:
- name: PNPLA6
  association: Loss of function mutation
  notes: >-
    Biallelic (homozygous or compound heterozygous) pathogenic variants in
    PNPLA6 (19p13.2), encoding neuropathy target esterase, cause BNS. Reported
    variants are predominantly missense, with frameshift, splice-altering, and
    nonsense variants also described; missense/in-frame variants are enriched in
    the catalytic phospholipase/esterase (patatin-like) domain. PNPLA6 is also
    the cause of allelic disorders on the same spectrum, including Gordon Holmes
    syndrome, Oliver-McFarlane syndrome, Laurence-Moon syndrome, and spastic
    paraplegia type 39.
  gene_term:
    preferred_term: PNPLA6
    term:
      id: hgnc:16268
      label: PNPLA6
  evidence:
  - reference: PMID:35198007
    reference_title: "Identification of Novel Compound Heterozygous Variants of the PNPLA6 Gene in Boucher-Neuhäuser Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Boucher-Neuhäuser syndrome (BNS, MIM 215470) is a rare autosomal recessive syndrome caused by mutations in the PNPLA6 gene.
    explanation: >-
      Directly identifies PNPLA6 as the causal gene for BNS.
  - reference: PMID:25267340
    reference_title: "Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      both mutations (one novel and one known) fell in the phospholipase esterase domain, where most pathogenic mutations seem to cluster
    explanation: >-
      Documents that pathogenic PNPLA6 variants in BNS cluster in the
      phospholipase esterase (catalytic) domain.
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A wide spectrum of neurodegenerative diseases has been associated with pathogenic variants in the PNPLA6 (patatin-like phospholipase domain-containing protein 6) gene, including spastic paraplegia type 39, Gordon-Holmes, Boucher-Neuhauser, Oliver-Mc Farlane, and Laurence-Moon syndromes.
    explanation: >-
      Establishes BNS as part of the broader allelic PNPLA6 disorder spectrum.
diagnosis:
- name: Molecular genetic testing
  description: >-
    Diagnosis is established in a proband with suggestive findings (cerebellar
    ataxia, chorioretinal dystrophy, hypogonadotropic hypogonadism) by
    identifying biallelic PNPLA6 pathogenic variants, typically via whole-exome
    sequencing with Sanger segregation. Functional NTE esterase-activity assays
    are an emerging adjunct for variant classification and phenotype prediction.
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The diagnosis of a PNPLA6 disorder is established in a proband with suggestive findings and biallelic PNPLA6 pathogenic variants identified on homologous alleles by molecular genetic testing.
    explanation: >-
      GeneReviews describes the molecular diagnostic approach for PNPLA6
      disorders, including BNS.
  - reference: PMID:35198007
    reference_title: "Identification of Novel Compound Heterozygous Variants of the PNPLA6 Gene in Boucher-Neuhäuser Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Gene sequencing is currently the primary diagnostic method.
    explanation: >-
      Confirms gene sequencing as the primary diagnostic modality for BNS.
treatments:
- name: Hormone replacement therapy
  description: >-
    Management is symptomatic. Hormone replacement therapy is given for the
    endocrine deficiencies: at the expected time of puberty for hypogonadotropic
    hypogonadism, during childhood/adolescence for growth hormone deficiency, and
    as soon as identified for hypothyroidism.
  treatment_term:
    preferred_term: Hormone replacement therapy
    term:
      id: NCIT:C15599
      label: Hormone Replacement Therapy
  target_mechanisms:
  - target: Hypothalamic-pituitary endocrine dysfunction
    treatment_effect: RESTORES
    description: Replaces deficient sex-hormone signaling at the expected time of puberty.
  - target: Anterior pituitary dysfunction
    treatment_effect: RESTORES
    description: Replaces deficient growth or thyroid hormone when indicated.
  target_phenotypes:
  - preferred_term: Hypogonadotropic hypogonadism
    term:
      id: HP:0000044
      label: Hypogonadotropic hypogonadism
  - preferred_term: Secondary growth hormone deficiency
    term:
      id: HP:0008240
      label: Secondary growth hormone deficiency
  - preferred_term: Pituitary hypothyroidism
    term:
      id: HP:0008245
      label: Pituitary hypothyroidism
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Hypogonadotropic hypogonadism. Hormone replacement therapy at the expected time of puberty.
    explanation: >-
      GeneReviews recommends hormone replacement therapy for the hypogonadotropic
      hypogonadism of PNPLA6 disorders.
- name: Supportive and rehabilitative care
  description: >-
    Symptomatic, individually tailored multidisciplinary care: continuous
    training of speech/swallowing, fine-motor skills, gait, and balance for
    ataxia; physical therapy, assistive walking devices, and antispasticity
    measures for spasticity; and low-vision aids and visual rehabilitation for
    chorioretinal dystrophy. Patients should avoid alcohol, obesity, a sedentary
    lifestyle, and medications/chemicals that exacerbate neuropathy.
  treatment_term:
    preferred_term: supportive care
    term:
      id: NCIT:C15747
      label: Supportive Care
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Management is symptomatic and individually tailored. Ataxia. Continuous training of speech and swallowing, fine-motor skills, gait, and balance.
    explanation: >-
      GeneReviews describes the symptomatic, multidisciplinary supportive
      management of PNPLA6 disorders.
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Agents/circumstances to avoid: Alcohol; obesity; inactive, sedentary lifestyle; exposure to medications or chemicals that exacerbate neuropathy.
    explanation: >-
      GeneReviews lists agents/circumstances to avoid, captured here as part of
      supportive management guidance.
- name: Genetic counseling
  description: >-
    Genetic counseling is recommended given autosomal recessive inheritance.
    Once the familial PNPLA6 variants are known, carrier testing for at-risk
    relatives, prenatal testing, and preimplantation genetic testing are
    possible.
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Once the PNPLA6 pathogenic variants in the family have been identified, carrier testing for at-risk relatives, prenatal testing for a pregnancy at increased risk, and preimplantation genetic testing are possible.
    explanation: >-
      GeneReviews describes the genetic-counseling options available for PNPLA6
      disorders.
datasets: []
📚

References & Deep Research

References

11
PMID:25299038
PNPLA6 Disorders.
No top-level findings curated for this source.
PMID:24355708
PNPLA6 mutations cause Boucher-Neuhauser and Gordon Holmes syndromes as part of a broad neurodegenerative spectrum.
No top-level findings curated for this source.
PMID:25267340
Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia.
No top-level findings curated for this source.
PMID:29749493
A novel PNPLA6 compound heterozygous mutation identified in a Chinese patient with Boucher‑Neuhäuser syndrome.
No top-level findings curated for this source.
PMID:31135245
Detailed retinal phenotype of Boucher-Neuhäuser syndrome associated with mutations in PNPLA6 mimicking choroideremia.
No top-level findings curated for this source.
PMID:35069422
Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature.
No top-level findings curated for this source.
PMID:35198007
Identification of Novel Compound Heterozygous Variants of the PNPLA6 Gene in Boucher-Neuhäuser Syndrome.
No top-level findings curated for this source.
PMID:35448471
PNPLA6/NTE, an Evolutionary Conserved Phospholipase Linked to a Group of Complex Human Diseases.
No top-level findings curated for this source.
PMID:37732399
PNPLA6 disorders: what's in a name?
No top-level findings curated for this source.
PMID:38683245
Two case reports of a novel missense mutation in the PNPLA6 gene in two siblings with chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia.
No top-level findings curated for this source.
PMID:38735647
Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders.
No top-level findings curated for this source.

Deep Research

1
Falcon ▸
1. Disease Information
Edison Scientific Literature 25 citations 2026-06-04T11:23:53.735110

1. Disease Information

1.1 What is the disease?

BNS is a multisystem neurodegenerative syndrome that presents with the triad: - Cerebellar ataxia / cerebellar degeneration - Hypogonadotropic hypogonadism (HH) (often described clinically within anterior hypopituitarism) - Chorioretinal dystrophy / retinal degeneration

Primary literature defines BNS as “the triad of early-onset autosomal recessive cerebellar ataxia (ARCA), hypogonadotropic hypogonadism, and chorioretinal dystrophy.” (deik2014compoundheterozygouspnpla6 pages 1-2)

1.2 Key identifiers

  • OMIM/MIM (disease): MIM #215470 (Boucher–Neuhäuser syndrome) (deik2014compoundheterozygouspnpla6 pages 1-2, he2022identificationofnovel pages 1-2)
  • OMIM/MIM (gene): PNPLA6 MIM *603197 (deik2014compoundheterozygouspnpla6 pages 1-2)
  • Other identifiers requested (Orphanet/ICD-10/ICD-11/MeSH/MONDO): Not found in the retrieved full-text excerpts; therefore cannot be asserted from this evidence set. (deik2014compoundheterozygouspnpla6 pages 1-2, he2022identificationofnovel pages 1-2)

1.3 Synonyms / alternative names

  • BNS (common abbreviation) (he2022identificationofnovel pages 1-2, liampas2024twocasereports pages 1-5)
  • Orthographic variants: Boucher–Neuhäuser, Boucher–Neuha¨user (deik2014compoundheterozygouspnpla6 pages 1-2)
  • Historical phenotype description: “familial ataxia, hypogonadism and retinal degeneration” (reported as a historical descriptor in reviews of PNPLA6 phenotypes) (nanetti2022multifacetedandagedependent pages 9-10)
  • Related/overlapping entities within PNPLA6 disorders: Gordon Holmes syndrome and others (deik2014compoundheterozygouspnpla6 pages 1-2, he2022identificationofnovel pages 1-2, liu2023pnpla6disorderswhat’s pages 3-4)

1.4 Evidence type (individual vs aggregated)

Evidence base is largely case reports/series aggregated in systematic reviews and cohort meta-analyses, including a large integrated dataset of published individuals with biallelic PNPLA6 variants (95 as of May 2023) and an expanded cohort of 118 individuals in later functional-genotype studies. (liu2023pnpla6disorderswhat’s pages 3-4, liu2024neuropathytargetesterase pages 4-6)

2. Etiology

2.1 Disease causal factors

Primary cause: biallelic pathogenic variants in PNPLA6, encoding neuropathy target esterase (NTE). BNS is repeatedly described as “a rare autosomal recessive syndrome caused by mutations in the PNPLA6 gene.” (he2022identificationofnovel pages 1-2)

Mechanistic framing: PNPLA6/NTE is an ER-associated patatin-like phospholipase/esterase involved in phospholipid homeostasis and trafficking; loss-of-function is supported by animal/cellular models. (liu2023pnpla6disorderswhat’s pages 1-3)

2.2 Risk factors

  • Genetic risk: having biallelic pathogenic PNPLA6 variants (autosomal recessive). (he2022identificationofnovel pages 1-2, deik2014compoundheterozygouspnpla6 pages 2-5)
  • Consanguinity can increase risk of homozygous variants (illustrated by affected siblings from a consanguineous family). (liampas2024twocasereports pages 1-5)

No environmental, infectious, or lifestyle risk factors specific to BNS were identified in the retrieved evidence.

2.3 Protective factors

No genetic or environmental protective factors were identified in the retrieved evidence.

2.4 Gene–environment interactions

Direct gene–environment interaction evidence for BNS is not present in the retrieved texts. Mechanistically, PNPLA6/NTE is historically linked to organophosphate-induced delayed neuropathy (OPIDN), which establishes environmental inhibition of NTE as neurotoxic, but this is not evidence of a specific GxE interaction for Mendelian BNS. (liu2023pnpla6disorderswhat’s pages 8-9)

3. Phenotypes

3.1 Core phenotype triad (with suggested HPO terms)

1) Cerebellar ataxia / cerebellar degeneration - Characteristics: variable onset (childhood to adulthood), often slowly progressive; MRI may show superior vermian/cerebellar atrophy. (deik2014compoundheterozygouspnpla6 pages 2-5, nanetti2022multifacetedandagedependent pages 3-5) - Suggested HPO: HP:0001251 (Ataxia); HP:0001272 (Cerebellar atrophy)

2) Hypogonadotropic hypogonadism / anterior hypopituitarism - Characteristics: may be recognized in the first two decades; hormone testing often shows low gonadotropins (LH/FSH) and broader pituitary hormone issues in the PNPLA6 spectrum. (deik2014compoundheterozygouspnpla6 pages 2-5, liampas2024twocasereports pages 1-5, liu2023pnpla6disorderswhat’s pages 3-4) - Suggested HPO: HP:0000044 (Hypogonadotropic hypogonadism); HP:0000871 (Hypopituitarism)

3) Chorioretinal dystrophy / retinal degeneration - Characteristics: onset widely variable (reported 1–64 years across PNPLA6 disorders); may mimic choroideremia; progression can lead to severe vision loss/blindness. (o’neil2019detailedretinalphenotype pages 6-7, liampas2024twocasereports pages 1-5, liu2023pnpla6disorderswhat’s pages 3-4) - Suggested HPO: HP:0000510 (Chorioretinal dystrophy); HP:0000546 (Retinal dystrophy); HP:0000505 (Visual impairment)

3.2 Additional, variably present features

  • Peripheral axonal neuropathy (less common in some BNS descriptions; present in cohorts of PNPLA6 disorders). (liampas2024twocasereports pages 1-5, nanetti2022multifacetedandagedependent pages 3-5)
  • HPO: HP:0003477 (Axonal neuropathy)
  • Oculomotor abnormalities (e.g., gaze-evoked nystagmus, saccadic pursuit) reported in case descriptions. (deik2014compoundheterozygouspnpla6 pages 2-5)
  • HPO: HP:0000639 (Nystagmus)
  • Cognitive impairment observed in a subset of PNPLA6 cohort cases. (nanetti2022multifacetedandagedependent pages 3-5)
  • HPO: HP:0100543 (Cognitive impairment)
  • Hair anomalies occur in a minority of PNPLA6 disorders (more characteristic of Oliver–McFarlane end of spectrum). (liu2023pnpla6disorderswhat’s pages 3-4)
  • HPO examples: HP:0002213 (Trichomegaly), HP:0001596 (Alopecia)

3.3 Frequency / statistics (best available from retrieved sources)

  • Review-level counts: 95 published individuals with biallelic PNPLA6 variants as of May 2023 (PNPLA6 disorders overall). (liu2023pnpla6disorderswhat’s pages 3-4)
  • Cerebellar atrophy/ataxia in up to ~90% of reported PNPLA6 cases. (liu2023pnpla6disorderswhat’s pages 3-4)
  • Case-series (8 novel PNPLA6 cases): 7/8 progressive cerebellar syndrome; 5/8 HH; 2/8 chorioretinal dystrophy; 4/8 peripheral axonal neuropathy and/or spasticity; 3/8 cognitive impairment. (nanetti2022multifacetedandagedependent pages 3-5)

3.4 Quality of life impact

Direct QoL instrument results (EQ-5D/SF-36/PROMIS) were not found in the retrieved texts. Based on clinical manifestations, major impacts include mobility limitations from ataxia and disability from progressive visual loss. (liampas2024twocasereports pages 1-5, liu2023pnpla6disorderswhat’s pages 3-4)

4. Genetic / Molecular Information

4.1 Causal gene(s)

  • PNPLA6 (patatin-like phospholipase domain-containing protein 6), encoding NTE. (he2022identificationofnovel pages 1-2, liu2023pnpla6disorderswhat’s pages 1-3)

4.2 Pathogenic variants (examples from primary literature)

BNS is caused by biallelic PNPLA6 variants (homozygous or compound heterozygous). Examples in retrieved sources include: - Compound heterozygous PNPLA6 mutations (e.g., p.Ser1045Leu and p.Ser1173Arg) in a genetically confirmed BNS case with late-onset ataxia. (deik2014compoundheterozygouspnpla6 pages 2-5) - Compound heterozygous variants including a frameshift and missense in a BNS case with predominantly retinal presentation (p.Arg1031GlnfsTer38 / p.Arg1183Gln). (o’neil2019detailedretinalphenotype pages 6-7) - Novel compound heterozygous variants identified by WES (c.2241del/p.Met748TrpfsTer65 and c.2986A>G/p.Thr996Ala) with RNA-level validation showing decreased PNPLA6 mRNA. (he2022identificationofnovel pages 1-2) - Homozygous missense c.3323G>A (p.Arg1108Gln) in two siblings. (liampas2024twocasereports pages 1-5)

Variant types reported across PNPLA6 disorders include missense, frameshift, splice-altering, and nonsense variants. In the Brain 2024 systematic cohort, 106 unique variants were summarized (70 missense; 35 predicted loss-of-function; 1 in-frame deletion), with enrichment of missense/in-frame variants in the catalytic domain. (liu2024neuropathytargetesterase pages 4-6)

4.3 Functional consequences

Multiple sources support loss-of-function as a principal mechanism, operationalized as reduced NTE hydrolase/esterase activity for many disease-associated variants. (liu2023pnpla6disorderswhat’s pages 1-3, liu2023neuropathytargetesterase pages 1-6)

4.4 Modifier genes / epigenetics / chromosomal abnormalities

No modifier genes, epigenetic signatures, or chromosomal abnormalities specific to BNS were identified in the retrieved evidence.

5. Environmental Information

No validated non-genetic environmental causes of Mendelian BNS were identified in the retrieved sources. However, PNPLA6/NTE is historically implicated in organophosphate neurotoxicity (OPIDN), indicating that environmental inhibition of NTE is neurotoxic in other contexts and motivates biomarker measurement in exposure studies. (liu2023pnpla6disorderswhat’s pages 8-9, NCT00671866 chunk 1)

6. Mechanism / Pathophysiology

6.1 Molecular function and pathways

PNPLA6 encodes NTE, described as a patatin-like serine hydrolase on the cytoplasmic face of the ER with: - Phospholipase B activity (deacylation of glycerophospholipids) - Strong lysophospholipase activity - Roles in phosphatidylcholine (PC) homeostasis (CDP-choline/Kennedy pathway), membrane trafficking, and axonal integrity. (liu2023pnpla6disorderswhat’s pages 1-3)

Suggested GO terms (biological process / molecular function; provisional) - GO:0006644 (phospholipid metabolic process) - GO:0004620 (phospholipase activity) - GO:0047499 (phospholipase B activity) - GO:0052689 (carboxylic ester hydrolase activity) - GO:0005789 (endoplasmic reticulum membrane; cellular component)

6.2 Causal chain (conceptual)

1) Biallelic PNPLA6 variants → 2) Reduced NTE enzymatic activity and disrupted phospholipid remodeling/homeostasis at ER membranes → 3) tissue vulnerability in retina (photoreceptors/RPE), cerebellum (Purkinje cell systems), and pituitary–gonadal axis → 4) clinical triad of retinopathy, ataxia, hypogonadotropic hypogonadism.

A key 2024 advance is that residual NTE activity can be used as a quantitative intermediate phenotype that predicts retinopathy and endocrinopathy risk. (liu2024neuropathytargetesterase pages 1-2, liu2024neuropathytargetesterase pages 7-9)

6.3 Recent (2023–2024) genotype:activity:phenotype relationships

In Brain (May 2024), Liu et al. report: - Cohort: 23 new + 95 reported individuals. (liu2024neuropathytargetesterase pages 1-2) - Variant functional assay: measured esterase activity for 46 disease-associated and 20 common variants; reclassified 36 as pathogenic and 10 as likely pathogenic. (liu2024neuropathytargetesterase pages 1-2) - Clinical subtype activity differences: SPG39 mean residual activity ~51% (n=12) vs BNHS ~28% (n=19) and OMCS/LNMS ~28% (n=26). (liu2024neuropathytargetesterase pages 4-6) - Mouse allelic series: <40% NTE activity was embryonic lethal; retinal degeneration onset ~40–50% residual activity. (liu2024neuropathytargetesterase pages 7-9)

These results support expert interpretation that PNPLA6 syndromic labels represent a continuum and that functional enzyme activity can serve both diagnostic and prognostic roles, potentially enabling trial stratification. (liu2024neuropathytargetesterase pages 1-2)

6.4 Model organism evidence (authoritative sources)

  • Chickens (OPIDN): OPIDN requires ~70% inhibition of NTE activity via “aging.” (liu2023pnpla6disorderswhat’s pages 8-9)
  • Drosophila (swiss-cheese; sws): sws loss causes rapid age-dependent neurodegeneration with ~20% more PC, ER stress signatures, and partial rescue by TUDCA (ER stress inhibitor). (liu2023pnpla6disorderswhat’s pages 8-9)
  • Mouse: global Pnpla6 knockout embryonic lethal; neuronal conditional KO shows hippocampal vacuolization, neuronal loss (including Purkinje cells) and axonal lesions. (liu2023pnpla6disorderswhat’s pages 8-9)

Suggested CL terms (cell types; provisional) - Purkinje cell: CL:0000121 - Retinal photoreceptor cell: CL:0000210 - Retinal pigment epithelial cell: CL:0000088

7. Anatomical Structures Affected

Organ/system level (with UBERON suggestions; provisional)

  • Cerebellum (UBERON:0002037) (deik2014compoundheterozygouspnpla6 pages 2-5, liu2023pnpla6disorderswhat’s pages 3-4)
  • Retina / choroid / RPE (UBERON:0000966 for retina; RPE is part of eye tissues) (o’neil2019detailedretinalphenotype pages 6-7, liu2023pnpla6disorderswhat’s pages 3-4)
  • Pituitary gland / hypothalamic–pituitary axis (UBERON:0000007 for pituitary) (liu2023pnpla6disorderswhat’s pages 3-4)

Subcellular localization

  • Endoplasmic reticulum membrane (GO:0005789) for PNPLA6/NTE. (liu2023pnpla6disorderswhat’s pages 1-3)

8. Temporal Development

Onset

Across PNPLA6 disorders (including BNS): - Gait disturbance: 1–55 years - Visual impairment: 1–64 years - Anterior hypopituitarism: birth–25 years - Hair anomalies: birth–18 years

These ranges reflect substantial heterogeneity and age-dependent penetrance of sub-phenotypes. (liu2023pnpla6disorderswhat’s pages 3-4)

Progression

Progression can be slow: - In an 8-patient PNPLA6 series, cerebellar symptoms had mean onset 31 years (range 9–55) and were “very slow” in progression; most had progressive cerebellar syndrome. (nanetti2022multifacetedandagedependent pages 3-5)

9. Inheritance and Population

Inheritance

  • Autosomal recessive inheritance due to biallelic PNPLA6 variants is consistently reported. (he2022identificationofnovel pages 1-2, liampas2024twocasereports pages 1-5)

Epidemiology

No prevalence/incidence per population was identified in the retrieved full texts. Best available “epidemiology-like” statistic is literature case count: - 95 published individuals with biallelic PNPLA6 variants (as of May 2023). (liu2023pnpla6disorderswhat’s pages 3-4)

Population genetics

No carrier frequency estimates or founder variants were identified in the retrieved evidence.

10. Diagnostics

10.1 Clinical tests / evaluations used in practice

Across case reports and reviews, diagnosis is typically assembled from multisystem evaluation: - Brain MRI: cerebellar atrophy, often vermian/superior cerebellar involvement. (deik2014compoundheterozygouspnpla6 pages 2-5, nanetti2022multifacetedandagedependent pages 3-5) - Ophthalmology: fundus exam, OCT, ERG, visual fields/perimetry; can reveal outer retinal loss and chorioretinal atrophy; presentations may mimic choroideremia, necessitating careful differential diagnosis. (deik2014compoundheterozygouspnpla6 pages 2-5, o’neil2019detailedretinalphenotype pages 6-7) - Endocrine testing: gonadotropins (LH/FSH), sex steroids; broader pituitary hormone panels depending on presentation. (deik2014compoundheterozygouspnpla6 pages 2-5, he2022identificationofnovel pages 1-2) - Neurophysiology: EMG/NCS for mild/subclinical axonal neuropathy. (deik2014compoundheterozygouspnpla6 pages 2-5)

10.2 Genetic testing

  • Whole-exome sequencing (WES) with segregation testing is commonly used; authors explicitly state “Gene sequencing is currently the primary diagnostic method.” (he2022identificationofnovel pages 1-2)
  • Emerging 2024 evidence supports adding functional NTE activity assays for variant classification and phenotype prediction. (liu2024neuropathytargetesterase pages 1-2)

10.3 Differential diagnosis

Not comprehensively enumerated in retrieved texts. One practical point is that PNPLA6-associated chorioretinal dystrophy can mimic choroideremia-like presentations, and thus PNPLA6 should be considered in diffuse chorioretinal atrophies with subtle systemic signs. (o’neil2019detailedretinalphenotype pages 6-7)

11. Outcome / Prognosis

Quantitative survival/life expectancy estimates were not found in the retrieved evidence.

Best available natural-history/prognosis statements: - Vision: chorioretinal dystrophy “leads to variable decreased visual acuity, even blindness.” (liampas2024twocasereports pages 1-5) - Some PNPLA6 disorders (milder spectrum) retain ambulation into adulthood with minimal/moderate aid. (liu2023pnpla6disorderswhat’s pages 3-4) - Slow progression of cerebellar syndrome has been reported with long disease duration in case series. (nanetti2022multifacetedandagedependent pages 3-5)

12. Treatment

No disease-modifying therapy is established in the retrieved evidence. Management is supportive and multidisciplinary.

12.1 Pharmacotherapy / endocrine replacement

  • Case report supportive regimen included hormone replacement therapy and vitamin supplementation (B12, C, E). (liampas2024twocasereports pages 1-5)

Suggested MAXO terms (provisional) - MAXO:0000258 (Hormone replacement therapy) - MAXO:0000747 (Vitamin supplementation)

12.2 Rehabilitation / supportive care

Direct rehabilitation trial data were not present in the retrieved texts. Based on multi-system involvement, supportive care typically includes neurology/ataxia management, vision support, and endocrine replacement/surveillance. (liu2023pnpla6disorderswhat’s pages 3-4, liampas2024twocasereports pages 1-5)

12.3 Experimental/clinical trials

No BNS-specific interventional trials were identified in the retrieved clinical-trials search. - An observational trial on organophosphate exposure measures NTE biomarkers but is not a therapeutic trial for BNS and lists “Peripheral Neuropathy” as condition (NCT00671866). (NCT00671866 chunk 1)

13. Prevention

No primary prevention exists for Mendelian BNS beyond reproductive/genetic counseling.

Secondary prevention conceptually includes: - Early recognition of retinal degeneration and pituitary hormone deficiencies for timely supportive interventions. (o’neil2019detailedretinalphenotype pages 6-7, liu2023pnpla6disorderswhat’s pages 3-4)

14. Other Species / Natural Disease

Naturally occurring BNS as a veterinary entity was not identified in the retrieved evidence.

However, PNPLA6 is evolutionarily conserved with an orthologue in Drosophila (swiss-cheese; sws) used to model neurodegeneration and lipid dysregulation. (liu2023pnpla6disorderswhat’s pages 8-9)

15. Model Organisms

Key models and how they recapitulate disease biology

  • Drosophila sws mutants: age-dependent neurodegeneration, altered phospholipids, ER stress; partial pharmacologic rescue (TUDCA). (liu2023pnpla6disorderswhat’s pages 8-9)
  • Mouse Pnpla6 allelic series (2024): demonstrates activity thresholds for viability and retinal degeneration and provides translational evidence for NTE activity as a biomarker. (liu2024neuropathytargetesterase pages 7-9)

Recent developments and expert analysis (2023–2024)

Conceptual shift: discrete syndromes → continuous PNPLA6 spectrum

A 2023 ophthalmic-genetics review frames PNPLA6-related conditions (including BNS) as “PNPLA6-opathies” across a spectrum and highlights a choroideremia-like retinal phenotype and multisystem involvement requiring integrated diagnosis. (liu2023pnpla6disorderswhat’s pages 3-4)

Functional stratification: NTE activity as diagnostic/prognostic biomarker (2024)

The 2024 Brain study provides a quantitative model linking biallelic genotype to residual NTE activity and to the probability of retinopathy/endocrinopathy, and proposes NTE as a biomarker “paving the way for therapeutic trials.” (liu2024neuropathytargetesterase pages 1-2)

Figure evidence supporting these claims is available from cropped panels showing (i) variant domain associations with retinopathy/endocrinopathy and (ii) activity-phenotype correlations and (iii) activity thresholds for retinopathy in vivo. (liu2024neuropathytargetesterase media cbbab372, liu2024neuropathytargetesterase media f1acab95, liu2024neuropathytargetesterase media d77bd8b8)

Key sources table (prioritizing 2023–2024)

Year Citation (first author, journal) Study type (review/case series/mechanistic) Key contributions for BNS (definition/triad; cohort size; key stats like NTE activity means/thresholds; diagnostic insights) URL/DOI Notes (PMID if known—leave blank if not present in text)
2024 Liu, Brain Mechanistic + cohort + systematic review PNPLA6 disorders placed on a continuous spectrum including Boucher–Neuhäuser syndrome (BNHS). Cohort: 23 new patients + 95 previously reported individuals. Functional assay measured 46 disease-associated and 20 common variants; 36 variants reclassified as pathogenic and 10 as likely pathogenic. Synthetic residual NTE activity differed by phenotype: SPG39 mean ~51% (n=12) vs BNHS ~28% (n=19) and OMCS/LNMS ~28% (n=26); lower activity associated with retinopathy/endocrinopathy, with reported threshold-type observations for endocrine/ophthalmic disease below ~32% and retinal degeneration around 40–50% residual activity; mouse data supported retinopathy threshold and embryonic lethality below 40% activity. Supports NTE activity as a biomarker for therapeutic trials. (liu2024neuropathytargetesterase pages 1-2, liu2024neuropathytargetesterase pages 4-6, liu2023neuropathytargetesterase pages 10-14, liu2024neuropathytargetesterase pages 7-9) https://doi.org/10.1093/brain/awae055
2023 Liu, Ophthalmic Genetics Review Defines five PNPLA6 disorders, including Boucher–Neuhäuser syndrome. States PNPLA6/NTE is involved in phospholipid homeostasis and trafficking; animal and cellular models support loss-of-function. As of May 2023, 95 published individuals with biallelic PNPLA6 variants. Cerebellar atrophy/ataxia reported in up to ~90% of cases. BNHS distinguished from Gordon–Holmes by added chorioretinal dystrophy. Diagnostic insights: neurological imaging for cerebellar atrophy, ERG/retinal imaging/visual fields for chorioretinal dystrophy, hormonal testing for anterior hypopituitarism, and exam for hair anomalies. (liu2023pnpla6disorderswhat’s pages 3-4, liu2023pnpla6disorderswhat’s pages 4-6, liu2023pnpla6disorderswhat’s pages 1-3) https://doi.org/10.1080/13816810.2023.2254830
2024 Liampas, Molecular Biology Reports Case reports Two siblings with a novel homozygous PNPLA6 missense variant. Reiterates classical BNS triad: hypogonadotropic hypogonadism, spinocerebellar ataxia, and chorioretinal dystrophy; notes peripheral axonal neuropathy can occur. Provides temporal guidance: HH often in first two decades; ataxia usually before early adulthood but can be late; chorioretinal dystrophy usually before age 50 and may progress to severe visual loss/blindness. Diagnostic workup included MRI, ophthalmologic assessment, endocrine evaluation, electrophysiology, WES and Sanger segregation. (liampas2024twocasereports pages 1-5) https://doi.org/10.1007/s11033-024-09515-4
2022 He, Frontiers in Genetics Case report + variant analysis/systematic review Defines BNS as a rare autosomal recessive PNPLA6 disorder with the triad of cerebellar ataxia, chorioretinal dystrophy, and hypogonadotropic hypogonadism; gives MIM 215470. Reports a 17-year-old with progressive night blindness from age 4, primary amenorrhea, absent secondary sexual development, retinal pigmentary degeneration, and CHH without current ataxia. Identified compound heterozygous PNPLA6 variants by WES; RT-PCR showed reduced PNPLA6 mRNA. Diagnostic insight: detailed ophthalmic exam, endocrine panels, pituitary/pelvic imaging, bone age X-ray, WES/Sanger; authors note gene sequencing is currently the primary diagnostic method. (he2022identificationofnovel pages 1-2) https://doi.org/10.3389/fgene.2022.810537
2022 Nanetti, Frontiers in Neurology Case series + literature review Reviews age-dependent PNPLA6 phenotypes and includes BN presentations. Across eight new PNPLA6 cases: 7/8 had cerebellar ataxia, 5/8 hypogonadotropic hypogonadism, 2/8 chorioretinal dystrophy; cerebellar symptoms mean onset 31 years (range 9–55) with very slow progression. Notes early-onset presentations may start with chorioretinal dystrophy, juvenile cases with HH, adult cases with ataxia. MRI may show cerebellar atrophy (often superior/dorsal vermis) and severe cerebellar atrophy in BN cases. Recommends multidisciplinary assessment and PNPLA6 screening in late-onset/cANVAS-like ataxia when RFC1 expansions are absent. (nanetti2022multifacetedandagedependent pages 9-10, nanetti2022multifacetedandagedependent pages 3-5) https://doi.org/10.3389/fneur.2021.793547
2019 O’Neil, Ophthalmic Genetics Deep phenotyping case report Shows that PNPLA6-associated BNS may present with predominantly retinal findings and subtle systemic abnormalities, mimicking choroideremia. Ophthalmic workup included SD-OCT, ERG, kinetic fields, autofluorescence imaging; systemic confirmation came from hypogonadotropic hypogonadism and cerebellar vermis hypoplasia on MRI. Highlights the need to consider PNPLA6/BNS in diffuse chorioretinal atrophies and to combine ophthalmic phenotyping with systemic review and genetic testing. (o’neil2019detailedretinalphenotype pages 6-7) https://doi.org/10.1080/13816810.2019.1605392
2014 Deik, Journal of Neurology Case report + genetics Landmark report confirming compound heterozygous PNPLA6 mutations as a cause of BNS with late-onset ataxia. Uses MIM #215470 for BNS and emphasizes the triad of autosomal recessive cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy. Diagnostic workup included fundoscopy/OCT, ERG, visual fields, endocrine testing (low LH/FSH), brain MRI showing superior cerebellar/vermian atrophy, EMG/NCS showing mild distal axonal neuropathy, and PNPLA6 sequencing. Also notes possible cognitive involvement and subclinical polyneuropathy. (deik2014compoundheterozygouspnpla6 pages 11-12, deik2014compoundheterozygouspnpla6 pages 2-5, deik2014compoundheterozygouspnpla6 pages 1-2) https://doi.org/10.1007/s00415-014-7516-3
2022 Kretzschmar, Metabolites Mechanistic review Reviews PNPLA6/NTE as an evolutionarily conserved phospholipase first linked to organophosphate-induced delayed neuropathy and later to inherited disorders including BNS. Summarizes normal role in lipid homeostasis and model-system evidence: mouse brain conditional knockout causes age-related neurodegeneration, complete knockout is embryonic lethal, and Drosophila swiss-cheese loss causes progressive locomotor defects and neurodegeneration. Useful for mechanistic context underlying BNS/PNPLA6 loss-of-function. (liu2023pnpla6disorderswhat’s pages 8-9) https://doi.org/10.3390/metabo12040284

Table: This table summarizes the most useful recent and foundational sources for Boucher–Neuhäuser syndrome within the broader PNPLA6 disorder spectrum. It highlights how each paper contributes evidence on definition, genotype–phenotype correlations, diagnostics, and mechanistic understanding.

Direct abstract quotes (as available in retrieved context)

  • He et al. 2022 (Frontiers in Genetics) abstract includes: “Boucher–Neuhäuser syndrome (BNS, MIM 215470) is a rare autosomal recessive syndrome caused by mutations in the PNPLA6 gene.” (he2022identificationofnovel pages 1-2)
  • O’Neil et al. 2019 abstract includes: “PNPLA6-associated retinal degenerations can present with predominantly retinal findings and subtle systemic abnormalities and should be considered in the differential diagnosis of diffuse chorioretinal atrophies.” (o’neil2019detailedretinalphenotype pages 6-7)

(Additional verbatim abstract text for Liu et al. 2024 and Liu & Hufnagel 2023 was not captured in the provided excerpts; therefore, only non-verbatim extraction is reported for those papers.) (liu2024neuropathytargetesterase pages 1-2, liu2023pnpla6disorderswhat’s pages 3-4)

Evidence gaps relative to the requested template

  • MONDO / Orphanet / ICD-10 / ICD-11 / MeSH identifiers: not present in retrieved full texts; would require direct querying of those databases.
  • Prevalence/incidence estimates: not provided in retrieved literature excerpts; current best quantitative evidence is published case counts.
  • Controlled treatment studies: no interventional trials specific to BNS identified in retrieved evidence.

References

  1. (deik2014compoundheterozygouspnpla6 pages 1-2): A. Deik, Brooke Johannes, J. Rucker, E. Sánchez, S. Brodie, E. Deegan, K. Landy, Y. Kajiwara, S. Scelsa, R. Saunders-Pullman, R. Saunders-Pullman, and C. Paisán-Ruiz. Compound heterozygous pnpla6 mutations cause boucher–neuhäuser syndrome with late-onset ataxia. Journal of Neurology, 261:2411-2423, Sep 2014. URL: https://doi.org/10.1007/s00415-014-7516-3, doi:10.1007/s00415-014-7516-3. This article has 44 citations and is from a domain leading peer-reviewed journal.

  2. (he2022identificationofnovel pages 1-2): Junyu He, Xin Liu, Liyi Liu, Shaohao Zeng, Shuanghong Shan, and Zhihong Liao. Identification of novel compound heterozygous variants of the pnpla6 gene in boucher–neuhäuser syndrome. Frontiers in Genetics, Feb 2022. URL: https://doi.org/10.3389/fgene.2022.810537, doi:10.3389/fgene.2022.810537. This article has 8 citations and is from a peer-reviewed journal.

  3. (liu2023pnpla6disorderswhat’s pages 3-4): James Liu and Robert B. Hufnagel. Pnpla6 disorders: what’s in a name? Ophthalmic Genetics, 44:530-538, Sep 2023. URL: https://doi.org/10.1080/13816810.2023.2254830, doi:10.1080/13816810.2023.2254830. This article has 15 citations and is from a peer-reviewed journal.

  4. (liu2024neuropathytargetesterase pages 1-2): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A Huryn, Yuri V Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H Németh, John Taylor, Susan Downes, Maciej R Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A Shear, Anthony T Moore, Jacque L Duncan, Beatriz Menendez, Sarah Hull, Andrea L Vincent, Carly E Siskind, Elias I Traboulsi, Craig Blackstone, Robert A Sisk, Virginia Miraldi Utz, Andrew R Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity defines phenotypes among pnpla6 disorders. Brain : a journal of neurology, 147:2085-2097, May 2024. URL: https://doi.org/10.1093/brain/awae055, doi:10.1093/brain/awae055. This article has 10 citations.

  5. (liu2024neuropathytargetesterase pages 4-6): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A Huryn, Yuri V Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H Németh, John Taylor, Susan Downes, Maciej R Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A Shear, Anthony T Moore, Jacque L Duncan, Beatriz Menendez, Sarah Hull, Andrea L Vincent, Carly E Siskind, Elias I Traboulsi, Craig Blackstone, Robert A Sisk, Virginia Miraldi Utz, Andrew R Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity defines phenotypes among pnpla6 disorders. Brain : a journal of neurology, 147:2085-2097, May 2024. URL: https://doi.org/10.1093/brain/awae055, doi:10.1093/brain/awae055. This article has 10 citations.

  6. (liampas2024twocasereports pages 1-5): Andreas Liampas, Paschalis Nicolaou, Christina Votsi, Anthi Georghiou, Kyproula Christodoulou, George A Tanteles, and Marios Pantzaris. Two case reports of a novel missense mutation in the pnpla6 gene in two siblings with chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia. Molecular biology reports, 51 1:590, Apr 2024. URL: https://doi.org/10.1007/s11033-024-09515-4, doi:10.1007/s11033-024-09515-4. This article has 0 citations and is from a peer-reviewed journal.

  7. (nanetti2022multifacetedandagedependent pages 9-10): Lorenzo Nanetti, Daniela Di Bella, Stefania Magri, Mario Fichera, Elisa Sarto, Anna Castaldo, Alessia Mongelli, Silvia Baratta, Silvia Fenu, Marco Moscatelli, Maria Teresa Bonati, Andrea Martinuzzi, Caterina Mariotti, and Franco Taroni. Multifaceted and age-dependent phenotypes associated with biallelic pnpla6 gene variants: eight novel cases and review of the literature. Frontiers in Neurology, Jan 2022. URL: https://doi.org/10.3389/fneur.2021.793547, doi:10.3389/fneur.2021.793547. This article has 18 citations and is from a peer-reviewed journal.

  8. (liu2023pnpla6disorderswhat’s pages 1-3): James Liu and Robert B. Hufnagel. Pnpla6 disorders: what’s in a name? Ophthalmic Genetics, 44:530-538, Sep 2023. URL: https://doi.org/10.1080/13816810.2023.2254830, doi:10.1080/13816810.2023.2254830. This article has 15 citations and is from a peer-reviewed journal.

  9. (deik2014compoundheterozygouspnpla6 pages 2-5): A. Deik, Brooke Johannes, J. Rucker, E. Sánchez, S. Brodie, E. Deegan, K. Landy, Y. Kajiwara, S. Scelsa, R. Saunders-Pullman, R. Saunders-Pullman, and C. Paisán-Ruiz. Compound heterozygous pnpla6 mutations cause boucher–neuhäuser syndrome with late-onset ataxia. Journal of Neurology, 261:2411-2423, Sep 2014. URL: https://doi.org/10.1007/s00415-014-7516-3, doi:10.1007/s00415-014-7516-3. This article has 44 citations and is from a domain leading peer-reviewed journal.

  10. (liu2023pnpla6disorderswhat’s pages 8-9): James Liu and Robert B. Hufnagel. Pnpla6 disorders: what’s in a name? Ophthalmic Genetics, 44:530-538, Sep 2023. URL: https://doi.org/10.1080/13816810.2023.2254830, doi:10.1080/13816810.2023.2254830. This article has 15 citations and is from a peer-reviewed journal.

  11. (nanetti2022multifacetedandagedependent pages 3-5): Lorenzo Nanetti, Daniela Di Bella, Stefania Magri, Mario Fichera, Elisa Sarto, Anna Castaldo, Alessia Mongelli, Silvia Baratta, Silvia Fenu, Marco Moscatelli, Maria Teresa Bonati, Andrea Martinuzzi, Caterina Mariotti, and Franco Taroni. Multifaceted and age-dependent phenotypes associated with biallelic pnpla6 gene variants: eight novel cases and review of the literature. Frontiers in Neurology, Jan 2022. URL: https://doi.org/10.3389/fneur.2021.793547, doi:10.3389/fneur.2021.793547. This article has 18 citations and is from a peer-reviewed journal.

  12. (o’neil2019detailedretinalphenotype pages 6-7): Erin O’Neil, Leona Serrano, Drew Scoles, Kayla E Cunningham, Grace Han, John Chiang, Jean Bennett, and Tomas S. Aleman. Detailed retinal phenotype of boucher-neuhäuser syndrome associated with mutations in pnpla6 mimicking choroideremia. Ophthalmic Genetics, 40:267-275, May 2019. URL: https://doi.org/10.1080/13816810.2019.1605392, doi:10.1080/13816810.2019.1605392. This article has 17 citations and is from a peer-reviewed journal.

  13. (liu2023neuropathytargetesterase pages 1-6): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A. Huryn, Yuri Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J. Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H. Németh, John Taylor, Susan Downes, Maciej Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A. Shear, Anthony T. Moore, Jacque L. Duncan, Beatriz Menendez, Sarah Hull, Andrea Vincent, Carly E. Siskind, Elias I. Traboulsi, Craig Blackstone, Robert Sisk, Virginia Utz, Andrew R. Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity predicts retinopathy among pnpla6 disorders. bioRxiv, Jun 2023. URL: https://doi.org/10.1101/2023.06.09.544373, doi:10.1101/2023.06.09.544373. This article has 1 citations.

  14. (NCT00671866 chunk 1): Neurotoxic Health Hazards of Long-Term Low-Level Exposure to Organophosphate (OP) Compounds in in Hula Valley. Shaare Zedek Medical Center. ClinicalTrials.gov Identifier: NCT00671866

  15. (liu2024neuropathytargetesterase pages 7-9): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A Huryn, Yuri V Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H Németh, John Taylor, Susan Downes, Maciej R Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A Shear, Anthony T Moore, Jacque L Duncan, Beatriz Menendez, Sarah Hull, Andrea L Vincent, Carly E Siskind, Elias I Traboulsi, Craig Blackstone, Robert A Sisk, Virginia Miraldi Utz, Andrew R Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity defines phenotypes among pnpla6 disorders. Brain : a journal of neurology, 147:2085-2097, May 2024. URL: https://doi.org/10.1093/brain/awae055, doi:10.1093/brain/awae055. This article has 10 citations.

  16. (liu2024neuropathytargetesterase media cbbab372): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A Huryn, Yuri V Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H Németh, John Taylor, Susan Downes, Maciej R Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A Shear, Anthony T Moore, Jacque L Duncan, Beatriz Menendez, Sarah Hull, Andrea L Vincent, Carly E Siskind, Elias I Traboulsi, Craig Blackstone, Robert A Sisk, Virginia Miraldi Utz, Andrew R Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity defines phenotypes among pnpla6 disorders. Brain : a journal of neurology, 147:2085-2097, May 2024. URL: https://doi.org/10.1093/brain/awae055, doi:10.1093/brain/awae055. This article has 10 citations.

  17. (liu2024neuropathytargetesterase media f1acab95): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A Huryn, Yuri V Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H Németh, John Taylor, Susan Downes, Maciej R Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A Shear, Anthony T Moore, Jacque L Duncan, Beatriz Menendez, Sarah Hull, Andrea L Vincent, Carly E Siskind, Elias I Traboulsi, Craig Blackstone, Robert A Sisk, Virginia Miraldi Utz, Andrew R Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity defines phenotypes among pnpla6 disorders. Brain : a journal of neurology, 147:2085-2097, May 2024. URL: https://doi.org/10.1093/brain/awae055, doi:10.1093/brain/awae055. This article has 10 citations.

  18. (liu2024neuropathytargetesterase media d77bd8b8): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A Huryn, Yuri V Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H Németh, John Taylor, Susan Downes, Maciej R Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A Shear, Anthony T Moore, Jacque L Duncan, Beatriz Menendez, Sarah Hull, Andrea L Vincent, Carly E Siskind, Elias I Traboulsi, Craig Blackstone, Robert A Sisk, Virginia Miraldi Utz, Andrew R Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity defines phenotypes among pnpla6 disorders. Brain : a journal of neurology, 147:2085-2097, May 2024. URL: https://doi.org/10.1093/brain/awae055, doi:10.1093/brain/awae055. This article has 10 citations.

  19. (liu2023neuropathytargetesterase pages 10-14): James Liu, Yi He, Cara Lwin, Marina Han, Bin Guan, Amelia Naik, Chelsea Bender, Nia Moore, Laryssa A. Huryn, Yuri Sergeev, Haohua Qian, Yong Zeng, Lijin Dong, Pinghu Liu, Jingqi Lei, Carl J. Haugen, Lev Prasov, Ruifang Shi, Hélène Dollfus, Petros Aristodemou, Yannik Laich, Andrea H. Németh, John Taylor, Susan Downes, Maciej Krawczynski, Isabelle Meunier, Melissa Strassberg, Jessica Tenney, Josephine Gao, Matthew A. Shear, Anthony T. Moore, Jacque L. Duncan, Beatriz Menendez, Sarah Hull, Andrea Vincent, Carly E. Siskind, Elias I. Traboulsi, Craig Blackstone, Robert Sisk, Virginia Utz, Andrew R. Webster, Michel Michaelides, Gavin Arno, Matthis Synofzik, and Robert B Hufnagel. Neuropathy target esterase activity predicts retinopathy among pnpla6 disorders. bioRxiv, Jun 2023. URL: https://doi.org/10.1101/2023.06.09.544373, doi:10.1101/2023.06.09.544373. This article has 1 citations.

  20. (liu2023pnpla6disorderswhat’s pages 4-6): James Liu and Robert B. Hufnagel. Pnpla6 disorders: what’s in a name? Ophthalmic Genetics, 44:530-538, Sep 2023. URL: https://doi.org/10.1080/13816810.2023.2254830, doi:10.1080/13816810.2023.2254830. This article has 15 citations and is from a peer-reviewed journal.

  21. (deik2014compoundheterozygouspnpla6 pages 11-12): A. Deik, Brooke Johannes, J. Rucker, E. Sánchez, S. Brodie, E. Deegan, K. Landy, Y. Kajiwara, S. Scelsa, R. Saunders-Pullman, R. Saunders-Pullman, and C. Paisán-Ruiz. Compound heterozygous pnpla6 mutations cause boucher–neuhäuser syndrome with late-onset ataxia. Journal of Neurology, 261:2411-2423, Sep 2014. URL: https://doi.org/10.1007/s00415-014-7516-3, doi:10.1007/s00415-014-7516-3. This article has 44 citations and is from a domain leading peer-reviewed journal.

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