Chromosome 17q12 Duplication Syndrome

Mendelian MONDO:0013796 Pathograph 27 Show in embeddings browser Chromosomal Duplication Syndrome

Chromosome 17q12 duplication syndrome is the copy-number gain at 17q12: a recurrent ~1.4-1.9 Mb interstitial duplication generated by non-allelic homologous recombination between the segmental duplications that flank the region. It is the reciprocal of the 17q12 deletion, and the two were described together in 2007 in the paper that called the pair "the first example of a recurrent genomic disorder associated with diabetes". The duplicated interval carries roughly 15 OMIM genes, of which HNF1B, LHX1 and ACACA are the ones the literature names. The two rearrangements are not mirror images clinically, and that asymmetry is the reason this entry is separate from the deletion entry rather than a subtype row on it. The deletion gives a comparatively specific renal-and-diabetes picture (RCAD / MODY5). The duplication gives a predominantly neurodevelopmental and neuropsychiatric one: learning disability of variable degree, delayed speech and delayed motor milestones, autism, epilepsy, behavioural problems, tics, and an increased risk of schizophrenia. Renal anomalies do occur, and esophageal and duodenal atresia are shared with the deletion, but they are far less consistent. Two features dominate any use of this entry. Penetrance is incomplete and expressivity is wide enough that the duplication is frequently inherited from an apparently unaffected parent; a three-generation family has been reported with full-scale IQ ranging from 52 to 99 among carriers. And the cohorts are ascertained in two quite different ways: series that recruit on the phenotype report a heavier burden than series that recruit on the duplication, which the Danish national cohort makes explicit and which is what makes prenatal counselling difficult. There is no disease-specific therapy; management is supportive and multidisciplinary.

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1
Mappings
1
Inheritance
5
Pathophys.
22
Phenotypes
2
Gaps
27
Pathograph
3
Genes
5
Medical Actions
1
Differentials
7
References
1
Deep Research
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Classifications

Harrison's Part
GENETICS ENVIRONMENT DISEASE NEUROLOGIC
🔗

Mappings

MONDO
MONDO:0013796 chromosome 17q12 duplication syndrome
skos:exactMatch MONDO
👪

Inheritance

1
Autosomal dominant inheritance HP:0000006
The duplication segregates as an autosomal dominant trait with reduced penetrance. GeneReviews puts the de novo fraction at about 10%, so roughly nine carriers in ten inherited it, usually from a parent who is minimally affected or phenotypically normal. That locus-specific figure is lower than the 34% de novo rate measured across recurrent neurodevelopmental CNVs as a class in newborn trios, which is recorded below for contrast rather than as a figure for this duplication. The combination of dominant transmission, reduced penetrance and wide expressivity is what makes the recurrence risk easy to state and the prognosis hard to.
Autosomal dominant inheritance
Show evidence (3 references)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"The 17q12 recurrent duplication is inherited in an autosomal dominant manner, with approximately 10% of duplications occurring de novo and approximately 90% inherited from a parent who is often minimally affected or phenotypically normal."
The locus-specific de novo and inherited fractions, from the GeneReviews chapter for this duplication. It is the figure to use; the class-wide newborn figure below is context.
PMID:30134084 SUPPORT Human Clinical
"The duplication is often inherited from an apparently unaffected parent."
The transmission pattern that dominates counselling for this locus, stated directly.
PMID:32778765 SUPPORT Human Clinical
"Approximately a third of the newborn recurrent NDD CNVs (34%, N = 20/59) are de novo variants."
The de novo fraction measured in an unselected newborn trio cohort. Note it is the figure for the 26 recurrent NDD CNVs together, not for 17q12 duplication specifically.
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Discussions and Knowledge Gaps

2
Which gene in the 17q12 interval carries the neurodevelopmental and neuropsychiatric signal of the duplication?
KNOWLEDGE GAP OPEN gap_17q12dup_which_gene_carries_the_neuropsychiatric_signal
Attached to
pathophysiology#Increased 17q12 Gene Dosage genetic#ACACA
Every mechanistic account of this syndrome routes through HNF1B, and the reason is historical rather than experimental: HNF1B is the gene whose point mutations cause MODY5 and renal cystic disease, so it was the gene everyone already knew about when the CNV was found. The only evidence that actually discriminates between interval genes points elsewhere, to a single tic-disorder case with a 110 kb duplication containing ACACA alone. One case cannot settle it, and the confidence interval on its odds ratio will be very wide, but it is the only observation in the literature that narrows the interval at all, and it does not narrow it onto HNF1B. The zebrafish overexpression result, which is the strongest mechanistic evidence for the gain direction, tests the HNF1B ortholog and so cannot distinguish the two hypotheses either. The stake is practical: if the neuropsychiatric phenotype is ACACA-driven, small intragenic duplications reported by microarray would need different interpretation from the canonical CNV.
Proposed experiments
Phenotype series of atypical, non-canonical 17q12 duplications
exp_17q12dup_atypical_cnv_breakpoint_series
Assemble carriers of 17q12 duplications whose breakpoints do not match the canonical NAHR interval, from clinical microarray archives, and compare neurodevelopmental and psychiatric outcome by which interval genes each duplication contains. Atypical breakpoints are the only natural experiment available for separating the interval's genes in humans.
What is the penetrance of the 17q12 duplication in an unselected carrier, as opposed to in a carrier ascertained through a clinic?
KNOWLEDGE GAP OPEN gap_17q12dup_penetrance_denominator
Attached to
prevalence#Danish national 17q12 cohort, phenotyped patients
Almost everything known about this syndrome's frequency comes from series that recruited on a phenotype, whether developmental delay, schizophrenia, tics or a fetal ultrasound anomaly, and the one cohort that separated index from non-index patients found a milder burden in those ascertained on the duplication. Newborn CNV screening gives a clean prevalence for recurrent NDD CNVs as a class, but not a duplication-specific penetrance, and the two published case-control odds ratios (schizophrenia, tics) are risk ratios rather than penetrance. The result is that a carrier found incidentally, for example on a prenatal microarray done for another indication, cannot be given a numeric risk for any of the features in this entry. That is the situation the prenatal literature describes as challenging counselling, and it is a gap in evidence rather than in mechanism.
Proposed experiments
Phenotype recall of 17q12 duplication carriers found in population biobanks
exp_17q12dup_biobank_recall
Identify 17q12 duplication carriers in unselected population biobanks with linked health records, and estimate the frequency of intellectual disability, autism, epilepsy, tic disorder, schizophrenia and renal anomaly among them without conditioning on any of those phenotypes.
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Pathophysiology

5
NAHR Between 17q12 Segmental Duplications
The 17q12 interval is flanked by segmental duplications that misalign during meiosis, so unequal crossing-over generates a reciprocal deletion and duplication at the same breakpoints. This architecture is why the rearrangement recurs independently in unrelated families rather than being inherited from a common ancestor, and why no founder haplotype or population is involved.
Genetic context allele_type: structural variant (recurrent copy-number gain) variant_origin: GERMLINE
Downstream
Increased 17q12 Gene Dosage The product of the unequal crossover is a third copy of the interval, so every gene inside it is present at one and a half times the normal dosage.
Show evidence (2 references)
PMID:17924346 SUPPORT Human Clinical
"We found that 6% of fetal material showed evidence of microdeletion or microduplication, including three independent events that likely resulted from unequal crossing-over between segmental duplications."
The recombination mechanism, from the study that first identified the 17q12 pair. It is the claim this node makes.
PMID:17924346 SUPPORT Human Clinical
"We also identified the reciprocal duplication, which appears to be enriched in samples from patients with epilepsy."
The first description of the duplication as a distinct entity, and the first statement of a neurological association for it.
Increased 17q12 Gene Dosage
Three copies of a ~1.4-1.9 Mb interval containing about 15 OMIM genes. The proteins are structurally normal; what is abnormal is how much of each there is. HNF1B is the gene the literature treats as the dosage-sensitive driver, with LHX1 and ACACA named alongside it. Which of the interval genes actually produces which feature is not established for the duplication, so this node deliberately claims dosage imbalance and not an HNF1B-specific mechanism.
HNF1B hgnc:11630 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves increased HNF1B (hgnc:11630). hgnc:11630 is a gene from the HUGO Gene Nomenclature Committee. ↑ INCREASED LHX1 hgnc:6593 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves increased LHX1 (hgnc:6593). hgnc:6593 is a gene from the HUGO Gene Nomenclature Committee. ↑ INCREASED ACACA hgnc:84 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves increased ACACA (hgnc:84). hgnc:84 is a gene from the HUGO Gene Nomenclature Committee. ↑ INCREASED
Downstream
Disrupted Regional Specification of Organ Primordia
Show evidence (2 references)
PMID:27409573 SUPPORT Human Clinical
"The aberrations encompass the genes, HNF1B, LHX1, and ACACA, among others."
The gene content of the interval, from the national cohort. It names the three genes this node binds and says explicitly that there are others.
PMID:40894066 SUPPORT Human Clinical
"Eight cases and one control carried the canonical ~1.4 Mb duplication at chr17:34.8 - 36.2 Mb, while one additional case had a smaller 110 kb duplication within this known CNV that included only one gene, ACACA"
The one published observation that narrows the interval: a 110 kb duplication containing only ACACA, in a single tic-disorder case. It is curated as a lead about which gene carries the neuropsychiatric signal, not as a demonstration.
Disrupted Regional Specification of Organ Primordia
HNF1B and LHX1 are transcription factors that pattern organ primordia, so an excess of them perturbs regional specification during the embryonic window. The direct evidence for the gain direction is from zebrafish: overexpressing the HNF1B ortholog vhnf1 expands the valentino expression domain in the hindbrain, which is a CNS patterning defect produced by too much rather than too little. The corresponding human experiment does not exist, so this node rests on a model-organism result and is graded accordingly.
anterior/posterior pattern specification GO:0009952 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal anterior/posterior pattern specification (GO:0009952). GO:0009952 is a biological process from the Gene Ontology. ⚠ ABNORMAL
brain UBERON:0000955 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in brain (UBERON:0000955). UBERON:0000955 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Neurodevelopmental and Neuropsychiatric Dysfunction
Variable Organ Malformation
Show evidence (2 references)
PMID:11731484 SUPPORT Model Organism
"Complementary to the loss-of-function phenotypes, overexpression of vhnf1 induces expansion of the val expression domain in the hindbrain."
The only direct evidence that excess HNF1B-family dosage perturbs CNS patterning. Everything else in the mechanism is inferred from the deletion or from the phenotype, so this sentence carries the gain-of-dosage step on its own.
PMID:11731484 SUPPORT Model Organism
"We propose that vhnf1 controls development of multiple organs through regulating regional specification of organ primordia."
The authors' framing of the gene's role, which is what makes one lesion plausibly responsible for both the neural and the organ branches below.
Neurodevelopmental and Neuropsychiatric Dysfunction
The dominant clinical consequence: learning disability of variable degree, delayed language and motor milestones, autism, epilepsy, behavioural problems, tics and increased schizophrenia risk. The spectrum is described as extremely wide, and the Danish cohort includes adults who obtained an academic degree.
Downstream
Intellectual disability
Delayed speech and language development
Motor delay
Autism
Seizure
Schizophrenia
Tics
Abnormal brain morphology
Hypotonia
Atypical behavior
Attention deficit hyperactivity disorder
Show evidence (2 references)
PMID:27409573 SUPPORT Human Clinical
"Patients with 17q12 duplications were characterized by an extremely wide phenotypic spectrum, including a variable degree of learning disabilities, delayed language development, delayed motor milestones, and a broad range of psychiatric and neurological features."
The clinical content of this node, from the largest phenotyped cohort.
PMID:27409573 SUPPORT Human Clinical
"This patient group also included adults achieving an academic degree."
The upper end of the range, quoted separately because it is the sentence that stops the node being read as uniformly severe.
Variable Organ Malformation
A second, much less consistent branch: structural and ocular anomalies outside the nervous system, comprising renal anomalies, esophageal atresia, duodenal atresia, cardiac malformation and strabismus. These overlap the deletion phenotype, and the literature had initially described duplication carriers as having no renal disorder before renal malformations were shown to be part of the duplication syndrome too. Strabismus is grouped here rather than with the neurodevelopmental branch because the sentence that puts it in the duplication phenotype is the same sentence that puts the two atresias there; no source separates the two mechanistically.
kidney UBERON:0002113 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in kidney (UBERON:0002113). UBERON:0002113 is an anatomical location from the Uberon multi-species anatomy ontology. duodenum UBERON:0002114 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in duodenum (UBERON:0002114). UBERON:0002114 is an anatomical location from the Uberon multi-species anatomy ontology. heart UBERON:0000948 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in heart (UBERON:0000948). UBERON:0000948 is an anatomical location from the Uberon multi-species anatomy ontology. eye UBERON:0000970 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in eye (UBERON:0000970). UBERON:0000970 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Abnormality of the kidney
Esophageal atresia
Duodenal atresia
Abnormal heart morphology
Strabismus
Show evidence (2 references)
PMID:21540130 SUPPORT Human Clinical
"Moreover, we showed herein, that renal malformations may be part of the 17q12 duplication syndrome."
The paper that added renal malformation to the duplication phenotype. Its own introduction states the prior belief it overturned, that duplication carriers had no renal disorder.
PMID:27409573 SUPPORT Human Clinical
"we extend the list of features seen in both patient categories to include strabismus, esophageal defects, and duodenal atresia."
Adds the two atresias to the shared deletion/duplication feature list, which is where this node's gastrointestinal content comes from.
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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 Chromosome 17q12 Duplication 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

22
Cardiovascular 1
Abnormal heart morphology OCCASIONAL HP:0001627 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Abnormal heart morphology (HP:0001627). HP:0001627 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Additional common findings include microcephaly, ocular abnormalities, and endocrine abnormalities. Short stature and renal and cardiac abnormalities are also reported in some individuals. Penetrance is reduced and clinical findings are variable."
The chapter reports short stature, renal and cardiac abnormalities in some individuals, which is the wording behind the OCCASIONAL band here.
Digestive 2
Esophageal atresia HP:0002032 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Esophageal atresia (HP:0002032). HP:0002032 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:21540130 SUPPORT Human Clinical
"Esophageal atresia (EA) type C was identified at birth in one patient while none had neurological disorder."
The esophageal lesion, and with it the observation that these two carriers had no neurological disorder at all, which is the variable-expressivity point in its sharpest form.
Duodenal atresia HP:0002247 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Duodenal atresia (HP:0002247). HP:0002247 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"we extend the list of features seen in both patient categories to include strabismus, esophageal defects, and duodenal atresia."
Adds duodenal atresia to the shared feature list. It is also the source for strabismus, which is curated separately below.
Endocrine 1
Abnormality of the endocrine system HP:0000818 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is endocrine abnormalities, annotated with Abnormality of the endocrine system (HP:0000818). HP:0000818 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Additional common findings include microcephaly, ocular abnormalities, and endocrine abnormalities. Short stature and renal and cardiac abnormalities are also reported in some individuals. Penetrance is reduced and clinical findings are variable."
The chapter's list of additional common findings. It does not name a specific endocrine abnormality, and this entry does not supply one.
Eye 2
Abnormality of the eye HP:0000478 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is ocular abnormalities, annotated with Abnormality of the eye (HP:0000478). HP:0000478 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Additional common findings include microcephaly, ocular abnormalities, and endocrine abnormalities. Short stature and renal and cardiac abnormalities are also reported in some individuals. Penetrance is reduced and clinical findings are variable."
The chapter's list of additional common findings. It does not say which ocular abnormalities, so nothing more specific can be bound.
Strabismus HP:0000486 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Strabismus (HP:0000486). HP:0000486 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"we extend the list of features seen in both patient categories to include strabismus, esophageal defects, and duodenal atresia."
Strabismus among the newly added shared features.
Genitourinary 1
Abnormality of the kidney HP:0000077 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Abnormality of the kidney (HP:0000077). HP:0000077 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:21540130 SUPPORT Human Clinical
"We report here two first-degree relatives carrying a 17q12 duplication and harboring various renal abnormalities (bilateral hypoplastic kidneys with vesico-ureteric reflux or multicystic dysplatic kidney with contralateral hyperechogenic kidney)."
The renal lesions in two genotyped duplication carriers, described individually rather than as a category.
Head and Neck 2
Microcephaly HP:0000252 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Microcephaly (HP:0000252). HP:0000252 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Additional common findings include microcephaly, ocular abnormalities, and endocrine abnormalities. Short stature and renal and cardiac abnormalities are also reported in some individuals. Penetrance is reduced and clinical findings are variable."
The chapter's list of additional common findings. Microcephaly, ocular abnormality, endocrine abnormality, short stature and cardiac abnormality on this entry all rest on this sentence, and it gives no numbers.
Abnormal facial shape HP:0001999 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Abnormal facial shape (HP:0001999). HP:0001999 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"We emphasize that renal disease, learning disability, behavioral abnormalities, epilepsy, autism, schizophrenia, structural brain abnormalities, facial dysmorphism, and joint laxity are features seen in both the 17q12 deletion syndrome and the reciprocal 17q12 duplication syndrome"
Facial dysmorphism among the shared features.
Musculoskeletal 2
Hypotonia FREQUENT HP:0001252 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hypotonia (HP:0001252). HP:0001252 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"The 17q12 recurrent duplication is characterized by intellectual abilities ranging from normal to severe disability and other variable clinical manifestations. Speech delay is common, and most affected individuals have some degree of hypotonia and gross motor delay."
The chapter's Clinical Characteristics summary, which names hypotonia and gross motor delay as present in most affected individuals and speech delay as common. The same sentence is the source for the range of intellectual ability recorded on this entry.
Joint hypermobility HP:0001382 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is joint laxity, annotated with Joint hypermobility (HP:0001382). HP:0001382 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"We emphasize that renal disease, learning disability, behavioral abnormalities, epilepsy, autism, schizophrenia, structural brain abnormalities, facial dysmorphism, and joint laxity are features seen in both the 17q12 deletion syndrome and the reciprocal 17q12 duplication syndrome"
Joint laxity among the shared features.
Nervous System 10
Intellectual disability FREQUENT HP:0001249 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Intellectual disability (HP:0001249). HP:0001249 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:30134084 SUPPORT Human Clinical
"Cognitive abilities range from normal function to moderate impairment (full-scale IQ range: 52-99)."
The measured range within a single family, which is evidence for variable expressivity rather than for a severity level.
Delayed speech and language development FREQUENT HP:0000750 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Delayed speech and language development (HP:0000750). HP:0000750 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"Patients with 17q12 duplications were characterized by an extremely wide phenotypic spectrum, including a variable degree of learning disabilities, delayed language development, delayed motor milestones, and a broad range of psychiatric and neurological features."
Language delay among the characteristic duplication features.
Motor delay FREQUENT HP:0001270 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Motor delay (HP:0001270). HP:0001270 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"Patients with 17q12 duplications were characterized by an extremely wide phenotypic spectrum, including a variable degree of learning disabilities, delayed language development, delayed motor milestones, and a broad range of psychiatric and neurological features."
Motor delay among the characteristic duplication features.
Autism HP:0000717 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Autism (HP:0000717). HP:0000717 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"We emphasize that renal disease, learning disability, behavioral abnormalities, epilepsy, autism, schizophrenia, structural brain abnormalities, facial dysmorphism, and joint laxity are features seen in both the 17q12 deletion syndrome and the reciprocal 17q12 duplication syndrome"
The list of features shared by the two rearrangements. Autism, epilepsy, structural brain anomalies, facial dysmorphism and joint laxity in this entry all rest on this sentence.
Atypical behavior OCCASIONAL HP:0000708 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Atypical behavior (HP:0000708). HP:0000708 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Behavioral and psychiatric conditions reported in some affected individuals include autism spectrum disorder, schizophrenia, and behavioral abnormalities"
The chapter's own grouping, and the source of the OCCASIONAL band: it says these conditions are reported in some affected individuals rather than in most. The quoted sentence continues with a parenthetical naming aggression and self-injury, which is where this row's description comes from.
PMID:27409573 SUPPORT Human Clinical
"We emphasize that renal disease, learning disability, behavioral abnormalities, epilepsy, autism, schizophrenia, structural brain abnormalities, facial dysmorphism, and joint laxity are features seen in both the 17q12 deletion syndrome and the reciprocal 17q12 duplication syndrome"
The cohort sentence that places behavioural abnormality in the duplication phenotype as well as the deletion's. It is the same sentence several other rows in this entry rest on.
Attention deficit hyperactivity disorder HP:0007018 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Attention deficit hyperactivity disorder (HP:0007018). HP:0007018 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:38379631 SUPPORT BACKGROUND Human Clinical
"It varies from asymptomatic to neurodevelopmental disorders, including developmental delay, attention deficit hyperkinetic disorder, epilepsy, autism spectrum disorder, intellectual disabilities, behavioral problems"
Places attention deficit disorder in the duplication's phenotypic range. The sentence opens the case report's introduction and summarizes prior literature rather than this patient, which is what the BACKGROUND role records.
PMID:41700275 SUPPORT Human Clinical
"The presence of a 17q12 duplication syndrome, in addition to diagnoses of ASD and ADHD, expands the spectrum of patients who may be at increased risk for this reaction."
A single carrier who carries the diagnosis. The sentence is making a point about drug susceptibility rather than about phenotype frequency, so it documents co-occurrence in one patient and nothing more.
Seizure FREQUENT HP:0001250 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Seizure (HP:0001250). HP:0001250 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Seizures are present in 36%."
The only numeric phenotype frequency GeneReviews gives for this duplication, and the basis for the FREQUENT band here. Nothing else in this entry has a comparable denominator.
PMID:17924346 SUPPORT Human Clinical
"We also identified the reciprocal duplication, which appears to be enriched in samples from patients with epilepsy."
The original epilepsy association. Note the authors' own hedge, "appears to be enriched", which is why no frequency is assigned to this phenotype.
Schizophrenia HP:0100753 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Schizophrenia (HP:0100753). HP:0100753 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:24776740 SUPPORT Human Clinical
"We report a novel association for 17q12 duplications (odds ratio=4.16, P=0.018), previously associated with autism and mental retardation but not SCZ."
The effect size and its p-value, from a case-control study of 4,719 cases and 5,917 controls. An odds ratio is a risk statement about carriers, not a frequency of schizophrenia among them, so no frequency band is assigned.
Tics HP:0100033 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Tics (HP:0100033). HP:0100033 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:40894066 SUPPORT Human Clinical
"Additionally, a novel, genome-wide significant CNV locus for TS/PTD was discovered, involving duplications at 17q12 (hg19 chr17:34.8 - 36.2 Mb)."
The association and its genomic coordinates, from a meta-analysis of 5,725 cases and 10,982 controls.
Abnormal brain morphology HP:0012443 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Abnormal brain morphology (HP:0012443). HP:0012443 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"We emphasize that renal disease, learning disability, behavioral abnormalities, epilepsy, autism, schizophrenia, structural brain abnormalities, facial dysmorphism, and joint laxity are features seen in both the 17q12 deletion syndrome and the reciprocal 17q12 duplication syndrome"
Structural brain abnormality among the shared features.
Growth 1
Short stature OCCASIONAL HP:0004322 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Short stature (HP:0004322). HP:0004322 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Additional common findings include microcephaly, ocular abnormalities, and endocrine abnormalities. Short stature and renal and cardiac abnormalities are also reported in some individuals. Penetrance is reduced and clinical findings are variable."
The chapter reports short stature, renal and cardiac abnormalities in some individuals, which is the wording behind the OCCASIONAL band here.
🧬

Genetic Associations

3
HNF1B
Gene: HNF1B hgnc:11630 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is HNF1B (hgnc:11630). hgnc:11630 is a gene from the HUGO Gene Nomenclature Committee. relationship_type: CAUSATIVE
Show evidence (1 reference)
PMID:17924346 SUPPORT Human Clinical
"One of the microdeletions, identified in a fetus with multicystic dysplastic kidneys, encompasses the TCF2 gene on 17q12, previously shown to be mutated in maturity-onset diabetes, as well as in a subset of pediatric renal abnormalities."
Establishes HNF1B (TCF2) as the gene of interest in the interval. Note it describes the deletion, which is exactly the inferential step this entry flags rather than hides.
LHX1
Gene: LHX1 hgnc:6593 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is LHX1 (hgnc:6593). hgnc:6593 is a gene from the HUGO Gene Nomenclature Committee. relationship_type: UNKNOWN
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"The aberrations encompass the genes, HNF1B, LHX1, and ACACA, among others."
Places LHX1 in the interval. That is the whole of what is established about its role here.
ACACA
Gene: ACACA hgnc:84 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is ACACA (hgnc:84). hgnc:84 is a gene from the HUGO Gene Nomenclature Committee. relationship_type: UNKNOWN
Show evidence (1 reference)
PMID:40894066 SUPPORT Human Clinical
"Eight cases and one control carried the canonical ~1.4 Mb duplication at chr17:34.8 - 36.2 Mb, while one additional case had a smaller 110 kb duplication within this known CNV that included only one gene, ACACA"
The single-case narrowing observation, quoted with its denominator rather than only its odds ratio.
💊

Medical Actions

5
Multidisciplinary supportive management
Action: multidisciplinary supportive careNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is multidisciplinary supportive care, annotated with Supportive Care (NCIT:C15747). NCIT:C15747 is a clinical intervention from the NCI Thesaurus. Ontology label: Supportive Care NCIT:C15747
Platform: Other
There is no disease-specific or curative treatment. Management is symptom-directed across developmental, psychiatric, renal, cardiac and surgical domains as each applies to the individual.
Mechanism Target:
Neurodevelopmental and Neuropsychiatric Dysfunction — Addresses the functional consequences of the neurodevelopmental phenotype. Nothing available modifies the gene dosage that causes it.
Show evidence (1 reference)
PMID:38379631 SUPPORT Human Clinical
"Treatment involves a multidisciplinary approach"
The management principle. It is a case report's framing rather than a guideline, which is the strongest statement available for this disorder.
Developmental, psychological and seizure surveillance
Action: clinical surveillanceNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is clinical surveillance, annotated with Clinical Evaluation (NCIT:C124351). NCIT:C124351 is a clinical intervention from the NCI Thesaurus. Ontology label: Clinical Evaluation NCIT:C124351
Platform: Other
GeneReviews specifies regular assessment of psychomotor development for every child with the duplication, psychological evaluation in both affected children and adults, monitoring for new-onset seizures, growth and nutritional assessment, and assessment of family needs at each visit. The adult psychological arm is the part most easily dropped, and it is the part the schizophrenia and tic associations argue for.
Mechanism Target:
Neurodevelopmental and Neuropsychiatric Dysfunction — Detects developmental, psychiatric and seizure manifestations early enough to intervene. It does not modify the underlying dosage imbalance.
Show evidence (2 references)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Regular assessment of psychomotor development is recommended for all children with the 17q12 recurrent duplication as well as psychological evaluation in both affected children and adults. Monitor for new-onset seizures, growth and nutritional assessment, and assessment of family needs at each visit."
The GeneReviews surveillance schedule for this duplication.
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Presymptomatic diagnosis and treatment is warranted in at-risk relatives to identify as early as possible those who would benefit from close assessment/monitoring of developmental milestones in childhood or psychological assessment/intervention through adulthood."
The recommendation to test and follow at-risk relatives, which is what makes cascade testing an intervention rather than only information.
Genetic counselling and cascade testing
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. Ontology label: Genetic Counseling NCIT:C15240
Platform: Other
Counselling is the intervention with the most to offer here and the hardest to deliver, because penetrance is incomplete, expressivity is wide, and the burden observed depends on whether the family was ascertained on the duplication or on a phenotype. The Danish cohort states that difference explicitly and offers it as material for prenatal counselling.
Mechanism Target:
NAHR Between 17q12 Segmental Duplications — Counselling acts on the lesion only in the reproductive sense: it addresses the recurrence risk of the non-allelic homologous recombination event and the transmission of an inherited duplication. It changes nothing downstream of the lesion in a person who already carries it.
Neurodevelopmental and Neuropsychiatric Dysfunction — Cascade testing identifies at-risk relatives early enough for developmental monitoring in childhood and psychological assessment in adulthood, which is the chapter's stated reason for testing them. The benefit is earlier detection, not modification of the phenotype.
Show evidence (2 references)
PMID:27409573 SUPPORT Human Clinical
"Assessing index patients and non-index patients separately, our observations illustrate that an overall milder disease burden is seen, in particular in patients with 17q12 duplications who are ascertained on the duplication rather than the phenotype. This evidence may be useful in prenatal counseling."
The ascertainment effect and the authors' own statement of its counselling use. This is the single most important sentence for anyone applying this entry's frequencies to a newly ascertained carrier.
PMID:39286125 SUPPORT BACKGROUND Human Clinical
"17q12 copy number variants (CNVs) have variable presentations and incomplete penetrance, challenging prenatal counseling and management"
States the counselling problem directly. It opens the paper's structured PURPOSE section, so it frames the study rather than reporting its result.
Neurologist-managed antiseizure therapy
Action: antiseizure pharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is antiseizure pharmacotherapy, annotated with Anticonvulsant Therapy (NCIT:C64172). NCIT:C64172 is a clinical intervention from the NCI Thesaurus. Ontology label: Anticonvulsant Therapy NCIT:C64172
Agent: valproic acid CHEBI:39867 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses valproic acid (CHEBI:39867). CHEBI:39867 is a therapeutic agent from Chemical Entities of Biological Interest.
Platform: Small molecule
GeneReviews directs that seizures be managed by a neurologist using standard practice; nothing about the duplication changes which antiseizure medicines are indicated. One caution is specific enough to record: a 14-year-old carrier on valproate monotherapy at therapeutic dosing, with no other risk factor, developed acute pancreatitis that resolved on discontinuation and was rated probable on the Naranjo scale. The authors state this genetic background had not previously been reported with valproate pancreatitis and that more evidence is needed, so this is a single-case signal rather than an established contraindication, and it is recorded that way here.
Mechanism Target:
Seizure — Suppresses the seizures that are present in 36% of carriers. It does not act on the dosage imbalance upstream of them.
Show evidence (3 references)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Seizures should be managed by a neurologist using standard practice."
The management instruction. It is deliberately unspecific about agent, which is why the valproate caution below is worth recording separately.
PMID:41700275 SUPPORT Human Clinical
"This adverse effect occurred with VPA monotherapy at therapeutic dosing in the absence of risk factors, in the setting of 17q12 duplication syndrome, ADHD, and ASD."
The observation itself, with the two features that make it worth recording: monotherapy and no other risk factor. Polypharmacy is the usual setting for this adverse reaction, so its absence is what leaves the duplication as a candidate.
PMID:41700275 SUPPORT Human Clinical
"Presence of a 17q12 duplication syndrome in association with VPA-induced pancreatitis has not been previously described, possibly suggesting a previously unknown susceptibility, although more evidence is needed."
The authors' own limit on the claim, quoted so that this treatment record cannot be read as asserting a susceptibility. One case with no rechallenge cannot establish one, and no pathophysiology node is created for it.
Feeding therapy
Action: feeding therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is feeding therapy, annotated with Swallowing Therapy (NCIT:C156237). NCIT:C156237 is a clinical intervention from the NCI Thesaurus. Ontology label: Swallowing Therapy NCIT:C156237
Platform: Behavioral / lifestyle
Feeding therapy as needed, one of the GeneReviews treatment-of-manifestations items. It follows from the hypotonia rather than from any gene-specific mechanism, and the chapter gives no frequency for feeding difficulty in this duplication.
Mechanism Target:
Hypotonia — Addresses the oral-motor consequence of the hypotonia. It does not treat the hypotonia itself.
Show evidence (1 reference)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"Seizures should be managed by a neurologist using standard practice. Feeding therapy as needed."
"Feeding therapy as needed" is the chapter's whole statement on it, and is quoted with the sentence before it because four words cannot evidence anything on their own. Nothing more specific is published for this duplication, and the terseness is the reason this row carries no frequency and no protocol.
🔬

Diagnosis

1
Chromosomal microarray analysis
The duplication is about 1.4 Mb, below the resolution of a karyotype, so chromosomal microarray is the diagnostic test. Prenatally, SNP-array or CNV-seq on amniotic fluid is the equivalent. Parental testing follows, because inheritance from an apparently unaffected parent is common and changes the recurrence risk.
Show evidence (3 references)
PMID:26925472 SUPPORT REVIEW SYNTHESIS Human Clinical
"The diagnosis is established in a proband by detection of the 1.4-megabase heterozygous recurrent duplication at chromosome 17q12 by chromosomal microarray testing or other genomic methods."
The GeneReviews diagnostic criterion, which fixes both the size of the canonical duplication and the test that establishes it.
PMID:27409573 SUPPORT Human Clinical
"17q12 deletions and duplications are two distinct, recurrent chromosomal aberrations usually diagnosed by chromosomal microarray analysis (CMA)."
Names the diagnostic modality for both rearrangements.
PMID:39433644 SUPPORT Human Clinical
"Peripheral blood from the parents was extracted to determine whether the CNVs in the fetuses were inherited or de novo."
The parental testing step, as performed in the prenatal series. It is what converts a fetal finding into a recurrence risk.
📈

Progression

3
Prenatal detection on ultrasound anomaly
Where the duplication is found before birth it is usually because a fetal ultrasound anomaly, renal or a duodenal "double bubble" or a cardiac finding, prompted amniocentesis and chromosomal microarray. Prenatal series are therefore enriched for the malformation end of the spectrum and say nothing about how a carrier ascertained any other way will present.
Show evidence (1 reference)
PMID:39433644 SUPPORT Human Clinical
"Retrospective data were collected for 16 fetuses diagnosed with 17q12 deletion and seven fetuses with 17q12 duplication through SNP-array during prenatal diagnosis at a single Chinese tertiary medical center from January 2017 to December 2023."
Describes the ascertainment route and its scale. Seven duplication fetuses is the whole prenatal duplication series, which is why its percentages are treated cautiously throughout this entry.
Childhood neurodevelopmental presentation
Developmental delay, speech delay, learning disability, autism, epilepsy, behavioural problems and tics emerge through childhood. The features are static rather than degenerative.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"Patients with 17q12 duplications were characterized by an extremely wide phenotypic spectrum, including a variable degree of learning disabilities, delayed language development, delayed motor milestones, and a broad range of psychiatric and neurological features."
The childhood phenotype as the national cohort describes it.
Adolescent and adult psychiatric presentation
Schizophrenia and psychosis have their own onset window in adolescence and adulthood, so a carrier assessed in childhood has not yet passed through the period of greatest psychiatric risk. The Swedish CNV study put the odds ratio for schizophrenia at about 4.
Show evidence (1 reference)
PMID:30134084 SUPPORT Human Clinical
"In light of recent reports of association of this locus with schizophrenia, we performed a detailed psychiatric assessment and confirmed that one family member has symptoms consistent with a diagnosis of schizophrenia and another has a prodromal syndrome with attenuated positive symptoms of psychosis."
Psychiatric outcomes in adult carriers of a family ascertained on a child's developmental delay, which is what makes the adult window a separate phase.
📊

Prevalence

2
Norwegian Mother, Father and Child Cohort newborns, 12,252 trios
Birth Prevalence 480.0 per 100,000 live births >1 in 1,000 (births)
0.48% of live-born children carry a deletion or duplication at one of the 13 recurrent neurodevelopmental CNV regions. This is the figure for all 26 CNVs together, not for the 17q12 duplication, and is recorded because it is the best-quality unselected denominator available. The same study reports the 17q12 deletion at about 1 in 4,000; it does not give a separate figure for the duplication, so no duplication-specific rate is curated here.
Show evidence (1 reference)
PMID:32778765 SUPPORT Human Clinical
"We estimate the total prevalence of recurrent NDD CNVs (duplications and deletions) in live-born children to 0.48% (95% C.I.: 0.37-0.62%), i.e., ~1 in 200 newborns has either a deletion or duplication in these NDDs associated regions."
The aggregate newborn prevalence and its confidence interval, from an unselected population cohort rather than a clinical referral series.
Danish national 17q12 cohort, phenotyped patients
Cases In Literature Ultra Rare
Twenty-six phenotyped duplication patients against 12 deletion patients in the Danish national cohort, from 19 index patients and 19 family members. The ratio of index to family members matters more than the total: the same paper shows that the burden differs between the two groups.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"We here describe a large national cohort of 12 phenotyped patients with 17q12 deletions and 26 phenotyped patients with 17q12 duplications."
The cohort composition, which is the denominator behind this entry's qualitative frequency statements.
🔀

Differential Diagnoses

1

Conditions with similar clinical presentations that must be differentiated from Chromosome 17q12 Duplication Syndrome:

Chromosome 17q12 deletion syndrome
Overlapping Features The reciprocal rearrangement at the same breakpoints. It shares renal disease, learning disability, behavioural abnormality, epilepsy, autism, schizophrenia, structural brain anomalies, facial dysmorphism and joint laxity with the duplication, but its renal and diabetes phenotype (RCAD / MODY5) is far more consistent. Microarray distinguishes them immediately; clinical features do not.
Distinguishing Features
  • Delayed language development, learning disability, kidney involvement and eye dysmorphism with strabismus are the features most consistently shared among deletion patients.
  • The duplication group is characterised instead by an extremely wide and less predictable spectrum, weighted toward neurodevelopmental and psychiatric features rather than renal disease and diabetes.
Show evidence (1 reference)
PMID:27409573 SUPPORT Human Clinical
"Delayed language development, learning disability, kidney involvement, and eye dysmorphism and strabismus were the most consistently shared features among patients with 17q12 deletion."
The deletion's own consistent-feature list, which is what the duplication has to be distinguished from.
{ }

Source YAML

click to show 
name: Chromosome 17q12 Duplication Syndrome
creation_date: "2026-09-17T16:17:48Z"
description: >-
  Chromosome 17q12 duplication syndrome is the copy-number gain at 17q12: a
  recurrent ~1.4-1.9 Mb interstitial duplication generated by non-allelic
  homologous recombination between the segmental duplications that flank the
  region. It is the reciprocal of the 17q12 deletion, and the two were described
  together in 2007 in the paper that called the pair "the first example of a
  recurrent genomic disorder associated with diabetes". The duplicated interval
  carries roughly 15 OMIM genes, of which HNF1B, LHX1 and ACACA are the ones the
  literature names.

  The two rearrangements are not mirror images clinically, and that asymmetry is
  the reason this entry is separate from the deletion entry rather than a
  subtype row on it. The deletion gives a comparatively specific
  renal-and-diabetes picture (RCAD / MODY5). The duplication gives a
  predominantly neurodevelopmental and neuropsychiatric one: learning disability
  of variable degree, delayed speech and delayed motor milestones, autism,
  epilepsy, behavioural problems, tics, and an increased risk of schizophrenia.
  Renal anomalies do occur, and esophageal and duodenal atresia are shared with
  the deletion, but they are far less consistent.

  Two features dominate any use of this entry. Penetrance is incomplete and
  expressivity is wide enough that the duplication is frequently inherited from
  an apparently unaffected parent; a three-generation family has been reported
  with full-scale IQ ranging from 52 to 99 among carriers. And the cohorts are
  ascertained in two quite different ways: series that recruit on the phenotype
  report a heavier burden than series that recruit on the duplication, which the
  Danish national cohort makes explicit and which is what makes prenatal
  counselling difficult. There is no disease-specific therapy; management is
  supportive and multidisciplinary.
synonyms:
- 17q12 duplication syndrome
- chromosome 17q12 microduplication syndrome
- 17q12 recurrent duplication
- dup(17)(q12)
- reciprocal 17q12 duplication
category: Mendelian
disease_term:
  preferred_term: chromosome 17q12 duplication syndrome
  term:
    id: MONDO:0013796
    label: chromosome 17q12 duplication syndrome
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0013796
      label: chromosome 17q12 duplication syndrome
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
parents:
- Chromosomal Duplication Syndrome
classifications:
  harrisons_chapter:
  - classification_value: GENETICS_ENVIRONMENT_DISEASE
  - classification_value: NEUROLOGIC
inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    The duplication segregates as an autosomal dominant trait with reduced
    penetrance. GeneReviews puts the de novo fraction at about 10%, so roughly
    nine carriers in ten inherited it, usually from a parent who is minimally
    affected or phenotypically normal. That locus-specific figure is lower than
    the 34% de novo rate measured across recurrent neurodevelopmental CNVs as a
    class in newborn trios, which is recorded below for contrast rather than as a
    figure for this duplication. The combination of dominant transmission,
    reduced penetrance and wide expressivity is what makes the recurrence risk
    easy to state and the prognosis hard to.
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      The 17q12 recurrent duplication is inherited in an autosomal dominant
      manner, with approximately 10% of duplications occurring de novo and
      approximately 90% inherited from a parent who is often minimally affected
      or phenotypically normal.
    explanation: >-
      The locus-specific de novo and inherited fractions, from the GeneReviews
      chapter for this duplication. It is the figure to use; the class-wide
      newborn figure below is context.
  - reference: PMID:30134084
    reference_title: "Chromosome 17q12 duplications: Further delineation of the range of psychiatric and clinical phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The duplication is often inherited from an apparently unaffected parent.
    explanation: >-
      The transmission pattern that dominates counselling for this locus, stated
      directly.
  - reference: PMID:32778765
    reference_title: Population prevalence and inheritance pattern of recurrent CNVs associated with neurodevelopmental disorders in 12,252 newborns and their parents.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Approximately a third of the newborn recurrent NDD CNVs (34%, N = 20/59)
      are de novo variants.
    explanation: >-
      The de novo fraction measured in an unselected newborn trio cohort. Note it
      is the figure for the 26 recurrent NDD CNVs together, not for 17q12
      duplication specifically.
prevalence:
- population: Norwegian Mother, Father and Child Cohort newborns, 12,252 trios
  measure_type: BIRTH_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 480.0
  rate_denominator: LIVE_BIRTHS
  notes: >-
    0.48% of live-born children carry a deletion or duplication at one of the 13
    recurrent neurodevelopmental CNV regions. This is the figure for all 26 CNVs
    together, not for the 17q12 duplication, and is recorded because it is the
    best-quality unselected denominator available. The same study reports the
    17q12 deletion at about 1 in 4,000; it does not give a separate figure for
    the duplication, so no duplication-specific rate is curated here.
  evidence:
  - reference: PMID:32778765
    reference_title: Population prevalence and inheritance pattern of recurrent CNVs associated with neurodevelopmental disorders in 12,252 newborns and their parents.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We estimate the total prevalence of recurrent NDD CNVs (duplications and
      deletions) in live-born children to 0.48% (95% C.I.: 0.37-0.62%), i.e.,
      ~1 in 200 newborns has either a deletion or duplication in these NDDs
      associated regions.
    explanation: >-
      The aggregate newborn prevalence and its confidence interval, from an
      unselected population cohort rather than a clinical referral series.
- population: Danish national 17q12 cohort, phenotyped patients
  measure_type: CASES_IN_LITERATURE
  prevalence_class: ULTRA_RARE
  notes: >-
    Twenty-six phenotyped duplication patients against 12 deletion patients in
    the Danish national cohort, from 19 index patients and 19 family members.
    The ratio of index to family members matters more than the total: the same
    paper shows that the burden differs between the two groups.
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We here describe a large national cohort of 12 phenotyped patients with
      17q12 deletions and 26 phenotyped patients with 17q12 duplications.
    explanation: >-
      The cohort composition, which is the denominator behind this entry's
      qualitative frequency statements.
progression:
- phase: Prenatal detection on ultrasound anomaly
  notes: >-
    Where the duplication is found before birth it is usually because a fetal
    ultrasound anomaly, renal or a duodenal "double bubble" or a cardiac finding,
    prompted amniocentesis and chromosomal microarray. Prenatal series are
    therefore enriched for the malformation end of the spectrum and say nothing
    about how a carrier ascertained any other way will present.
  evidence:
  - reference: PMID:39433644
    reference_title: "Prenatal diagnosis, ultrasound findings, and pregnancy outcome of 17q12 deletion and duplication syndromes: a retrospective case series."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Retrospective data were collected for 16 fetuses diagnosed with 17q12
      deletion and seven fetuses with 17q12 duplication through SNP-array during
      prenatal diagnosis at a single Chinese tertiary medical center from January
      2017 to December 2023.
    explanation: >-
      Describes the ascertainment route and its scale. Seven duplication fetuses
      is the whole prenatal duplication series, which is why its percentages are
      treated cautiously throughout this entry.
- phase: Childhood neurodevelopmental presentation
  notes: >-
    Developmental delay, speech delay, learning disability, autism, epilepsy,
    behavioural problems and tics emerge through childhood. The features are
    static rather than degenerative.
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients with 17q12 duplications were characterized by an extremely wide
      phenotypic spectrum, including a variable degree of learning disabilities,
      delayed language development, delayed motor milestones, and a broad range
      of psychiatric and neurological features.
    explanation: The childhood phenotype as the national cohort describes it.
- phase: Adolescent and adult psychiatric presentation
  notes: >-
    Schizophrenia and psychosis have their own onset window in adolescence and
    adulthood, so a carrier assessed in childhood has not yet passed through the
    period of greatest psychiatric risk. The Swedish CNV study put the odds ratio
    for schizophrenia at about 4.
  evidence:
  - reference: PMID:30134084
    reference_title: "Chromosome 17q12 duplications: Further delineation of the range of psychiatric and clinical phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In light of recent reports of association of this locus with schizophrenia,
      we performed a detailed psychiatric assessment and confirmed that one
      family member has symptoms consistent with a diagnosis of schizophrenia and
      another has a prodromal syndrome with attenuated positive symptoms of
      psychosis.
    explanation: >-
      Psychiatric outcomes in adult carriers of a family ascertained on a child's
      developmental delay, which is what makes the adult window a separate phase.
pathophysiology:
- name: NAHR Between 17q12 Segmental Duplications
  biological_scale: MOLECULAR
  description: >-
    The 17q12 interval is flanked by segmental duplications that misalign during
    meiosis, so unequal crossing-over generates a reciprocal deletion and
    duplication at the same breakpoints. This architecture is why the
    rearrangement recurs independently in unrelated families rather than being
    inherited from a common ancestor, and why no founder haplotype or population
    is involved.
  genetic_context:
    variant_origin: GERMLINE
    allele_type: structural variant (recurrent copy-number gain)
  downstream:
  - target: Increased 17q12 Gene Dosage
    causal_link_type: DIRECT
    description: >-
      The product of the unequal crossover is a third copy of the interval, so
      every gene inside it is present at one and a half times the normal dosage.
  evidence:
  - reference: PMID:17924346
    reference_title: Recurrent reciprocal genomic rearrangements of 17q12 are associated with renal disease, diabetes, and epilepsy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We found that 6% of fetal material showed evidence of microdeletion or
      microduplication, including three independent events that likely resulted
      from unequal crossing-over between segmental duplications.
    explanation: >-
      The recombination mechanism, from the study that first identified the 17q12
      pair. It is the claim this node makes.
  - reference: PMID:17924346
    reference_title: Recurrent reciprocal genomic rearrangements of 17q12 are associated with renal disease, diabetes, and epilepsy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We also identified the reciprocal duplication, which appears to be enriched
      in samples from patients with epilepsy.
    explanation: >-
      The first description of the duplication as a distinct entity, and the
      first statement of a neurological association for it.
- name: Increased 17q12 Gene Dosage
  biological_scale: MOLECULAR
  description: >-
    Three copies of a ~1.4-1.9 Mb interval containing about 15 OMIM genes. The
    proteins are structurally normal; what is abnormal is how much of each there
    is. HNF1B is the gene the literature treats as the dosage-sensitive driver,
    with LHX1 and ACACA named alongside it. Which of the interval genes actually
    produces which feature is not established for the duplication, so this node
    deliberately claims dosage imbalance and not an HNF1B-specific mechanism.
  genes:
  - preferred_term: HNF1B
    modifier: INCREASED
    term:
      id: hgnc:11630
      label: HNF1B
  - preferred_term: LHX1
    modifier: INCREASED
    term:
      id: hgnc:6593
      label: LHX1
  - preferred_term: ACACA
    modifier: INCREASED
    term:
      id: hgnc:84
      label: ACACA
  downstream:
  - target: Disrupted Regional Specification of Organ Primordia
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The aberrations encompass the genes, HNF1B, LHX1, and ACACA, among others.
    explanation: >-
      The gene content of the interval, from the national cohort. It names the
      three genes this node binds and says explicitly that there are others.
  - reference: PMID:40894066
    reference_title: Persistent Tic Disorders Are Associated With 17q12 Duplications.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Eight cases and one control carried the canonical ~1.4 Mb duplication at
      chr17:34.8 - 36.2 Mb, while one additional case had a smaller 110 kb
      duplication within this known CNV that included only one gene, ACACA
    explanation: >-
      The one published observation that narrows the interval: a 110 kb
      duplication containing only ACACA, in a single tic-disorder case. It is
      curated as a lead about which gene carries the neuropsychiatric signal, not
      as a demonstration.
- name: Disrupted Regional Specification of Organ Primordia
  biological_scale: TISSUE
  description: >-
    HNF1B and LHX1 are transcription factors that pattern organ primordia, so an
    excess of them perturbs regional specification during the embryonic window.
    The direct evidence for the gain direction is from zebrafish: overexpressing
    the HNF1B ortholog vhnf1 expands the valentino expression domain in the
    hindbrain, which is a CNS patterning defect produced by too much rather than
    too little. The corresponding human experiment does not exist, so this node
    rests on a model-organism result and is graded accordingly.
  biological_processes:
  - preferred_term: anterior/posterior pattern specification
    modifier: ABNORMAL
    term:
      id: GO:0009952
      label: anterior/posterior pattern specification
  locations:
  - preferred_term: brain
    term:
      id: UBERON:0000955
      label: brain
  downstream:
  - target: Neurodevelopmental and Neuropsychiatric Dysfunction
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Variable Organ Malformation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: PMID:11731484
    reference_title: "vhnf1, the MODY5 and familial GCKD-associated gene, regulates regional specification of the zebrafish gut, pronephros, and hindbrain."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Complementary to the loss-of-function phenotypes, overexpression of vhnf1
      induces expansion of the val expression domain in the hindbrain.
    explanation: >-
      The only direct evidence that excess HNF1B-family dosage perturbs CNS
      patterning. Everything else in the mechanism is inferred from the deletion
      or from the phenotype, so this sentence carries the gain-of-dosage step on
      its own.
  - reference: PMID:11731484
    reference_title: "vhnf1, the MODY5 and familial GCKD-associated gene, regulates regional specification of the zebrafish gut, pronephros, and hindbrain."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      We propose that vhnf1 controls development of multiple organs through
      regulating regional specification of organ primordia.
    explanation: >-
      The authors' framing of the gene's role, which is what makes one lesion
      plausibly responsible for both the neural and the organ branches below.
- name: Neurodevelopmental and Neuropsychiatric Dysfunction
  biological_scale: ORGANISM
  description: >-
    The dominant clinical consequence: learning disability of variable degree,
    delayed language and motor milestones, autism, epilepsy, behavioural
    problems, tics and increased schizophrenia risk. The spectrum is described as
    extremely wide, and the Danish cohort includes adults who obtained an
    academic degree.
  downstream:
  - target: Intellectual disability
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Delayed speech and language development
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Motor delay
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Autism
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Seizure
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Schizophrenia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Tics
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Abnormal brain morphology
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Hypotonia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Atypical behavior
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Attention deficit hyperactivity disorder
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients with 17q12 duplications were characterized by an extremely wide
      phenotypic spectrum, including a variable degree of learning disabilities,
      delayed language development, delayed motor milestones, and a broad range
      of psychiatric and neurological features.
    explanation: The clinical content of this node, from the largest phenotyped cohort.
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This patient group also included adults achieving an academic degree.
    explanation: >-
      The upper end of the range, quoted separately because it is the sentence
      that stops the node being read as uniformly severe.
- name: Variable Organ Malformation
  biological_scale: ORGANISM
  description: >-
    A second, much less consistent branch: structural and ocular anomalies
    outside the nervous system, comprising renal anomalies, esophageal atresia,
    duodenal atresia, cardiac malformation and strabismus. These overlap the
    deletion phenotype, and the literature had initially described duplication
    carriers as having no renal disorder before renal malformations were shown to
    be part of the duplication syndrome too. Strabismus is grouped here rather
    than with the neurodevelopmental branch because the sentence that puts it in
    the duplication phenotype is the same sentence that puts the two atresias
    there; no source separates the two mechanistically.
  locations:
  - preferred_term: kidney
    term:
      id: UBERON:0002113
      label: kidney
  - preferred_term: duodenum
    term:
      id: UBERON:0002114
      label: duodenum
  - preferred_term: heart
    term:
      id: UBERON:0000948
      label: heart
  - preferred_term: eye
    term:
      id: UBERON:0000970
      label: eye
  downstream:
  - target: Abnormality of the kidney
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Esophageal atresia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Duodenal atresia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Abnormal heart morphology
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Strabismus
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: PMID:21540130
    reference_title: A 17q12 chromosomal duplication associated with renal disease and esophageal atresia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Moreover, we showed herein, that renal malformations may be part of the
      17q12 duplication syndrome.
    explanation: >-
      The paper that added renal malformation to the duplication phenotype. Its
      own introduction states the prior belief it overturned, that duplication
      carriers had no renal disorder.
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we extend the list of features seen in both patient categories to include
      strabismus, esophageal defects, and duodenal atresia.
    explanation: >-
      Adds the two atresias to the shared deletion/duplication feature list,
      which is where this node's gastrointestinal content comes from.
phenotypes:
- category: Neurologic
  name: Intellectual disability
  description: >-
    Learning disability of variable degree. In the reported three-generation
    family, full-scale IQ among carriers ranged from 52 to 99, which is the
    clearest single statement of how wide the range is within one duplication and
    one family.
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  frequency: FREQUENT
  evidence:
  - reference: PMID:30134084
    reference_title: "Chromosome 17q12 duplications: Further delineation of the range of psychiatric and clinical phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Cognitive abilities range from normal function to moderate impairment
      (full-scale IQ range: 52-99).
    explanation: >-
      The measured range within a single family, which is evidence for variable
      expressivity rather than for a severity level.
- category: Neurologic
  name: Delayed speech and language development
  description: >-
    Delayed language development, one of the features the national cohort names
    as characteristic of the duplication group.
  phenotype_term:
    preferred_term: Delayed speech and language development
    term:
      id: HP:0000750
      label: Delayed speech and language development
  frequency: FREQUENT
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients with 17q12 duplications were characterized by an extremely wide
      phenotypic spectrum, including a variable degree of learning disabilities,
      delayed language development, delayed motor milestones, and a broad range
      of psychiatric and neurological features.
    explanation: Language delay among the characteristic duplication features.
- category: Neurologic
  name: Motor delay
  description: Delayed motor milestones.
  phenotype_term:
    preferred_term: Motor delay
    term:
      id: HP:0001270
      label: Motor delay
  frequency: FREQUENT
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients with 17q12 duplications were characterized by an extremely wide
      phenotypic spectrum, including a variable degree of learning disabilities,
      delayed language development, delayed motor milestones, and a broad range
      of psychiatric and neurological features.
    explanation: Motor delay among the characteristic duplication features.
- category: Neurologic
  name: Hypotonia
  description: >-
    Hypotonia to some degree in most affected individuals, per the GeneReviews
    chapter. It is not reported in the Danish cohort's feature list, so this
    phenotype rests on the chapter alone.
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  frequency: FREQUENT
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      The 17q12 recurrent duplication is characterized by intellectual abilities
      ranging from normal to severe disability and other variable clinical
      manifestations. Speech delay is common, and most affected individuals have
      some degree of hypotonia and gross motor delay.
    explanation: >-
      The chapter's Clinical Characteristics summary, which names hypotonia and
      gross motor delay as present in most affected individuals and speech delay
      as common. The same sentence is the source for the range of intellectual
      ability recorded on this entry.
- category: Craniofacial
  name: Microcephaly
  description: >-
    Microcephaly, named by GeneReviews among the additional common findings. No
    frequency is given for it.
  phenotype_term:
    preferred_term: Microcephaly
    term:
      id: HP:0000252
      label: Microcephaly
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Additional common findings include microcephaly,
      ocular abnormalities, and endocrine abnormalities. Short stature and renal
      and cardiac abnormalities are also reported in some individuals. Penetrance
      is reduced and clinical findings are variable.
    explanation: >-
      The chapter's list of additional common findings. Microcephaly, ocular
      abnormality, endocrine abnormality, short stature and cardiac abnormality
      on this entry all rest on this sentence, and it gives no numbers.
- category: Ophthalmologic
  name: Abnormality of the eye
  description: >-
    Ocular abnormalities, named by GeneReviews among the additional common
    findings without being specified further. The binding is deliberately at the
    level the source states, which is the whole organ.
  phenotype_term:
    preferred_term: ocular abnormalities
    term:
      id: HP:0000478
      label: Abnormality of the eye
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Additional common findings include microcephaly,
      ocular abnormalities, and endocrine abnormalities. Short stature and renal
      and cardiac abnormalities are also reported in some individuals. Penetrance
      is reduced and clinical findings are variable.
    explanation: >-
      The chapter's list of additional common findings. It does not say which
      ocular abnormalities, so nothing more specific can be bound.
- category: Endocrine
  name: Abnormality of the endocrine system
  description: >-
    Endocrine abnormalities, named by GeneReviews among the additional common
    findings without being specified. Given HNF1B's role in pancreatic
    development and the deletion's MODY5 phenotype, this is the feature where a
    more specific term would be most useful and is least supported.
  phenotype_term:
    preferred_term: endocrine abnormalities
    term:
      id: HP:0000818
      label: Abnormality of the endocrine system
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Additional common findings include microcephaly,
      ocular abnormalities, and endocrine abnormalities. Short stature and renal
      and cardiac abnormalities are also reported in some individuals. Penetrance
      is reduced and clinical findings are variable.
    explanation: >-
      The chapter's list of additional common findings. It does not name a
      specific endocrine abnormality, and this entry does not supply one.
- category: Growth
  name: Short stature
  description: Short stature, reported in some individuals.
  phenotype_term:
    preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Additional common findings include microcephaly,
      ocular abnormalities, and endocrine abnormalities. Short stature and renal
      and cardiac abnormalities are also reported in some individuals. Penetrance
      is reduced and clinical findings are variable.
    explanation: >-
      The chapter reports short stature, renal and cardiac abnormalities in some
      individuals, which is the wording behind the OCCASIONAL band here.
- category: Cardiovascular
  name: Abnormal heart morphology
  description: >-
    Cardiac abnormality, reported in some individuals. The prenatal series
    reported cardiac malformation in four of seven duplication fetuses, but that
    series was ascertained on ultrasound anomalies, so its proportion is not a
    frequency for the disease.
  phenotype_term:
    preferred_term: Abnormal heart morphology
    term:
      id: HP:0001627
      label: Abnormal heart morphology
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Additional common findings include microcephaly,
      ocular abnormalities, and endocrine abnormalities. Short stature and renal
      and cardiac abnormalities are also reported in some individuals. Penetrance
      is reduced and clinical findings are variable.
    explanation: >-
      The chapter reports short stature, renal and cardiac abnormalities in some
      individuals, which is the wording behind the OCCASIONAL band here.
- category: Behavioral
  name: Autism
  description: >-
    Autism spectrum disorder, seen in both the deletion and duplication groups
    and reported in single-case detail for the duplication.
  phenotype_term:
    preferred_term: Autism
    term:
      id: HP:0000717
      label: Autism
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We emphasize that renal disease, learning disability, behavioral
      abnormalities, epilepsy, autism, schizophrenia, structural brain
      abnormalities, facial dysmorphism, and joint laxity are features seen in
      both the 17q12 deletion syndrome and the reciprocal 17q12 duplication
      syndrome
    explanation: >-
      The list of features shared by the two rearrangements. Autism, epilepsy,
      structural brain anomalies, facial dysmorphism and joint laxity in this
      entry all rest on this sentence.
- category: Behavioral
  name: Atypical behavior
  description: >-
    Behavioural abnormality, specified by GeneReviews as aggression and
    self-injury and named in the Danish cohort's list of features shared by the
    deletion and the duplication. It is distinct from the autism and tic rows,
    which are separate diagnoses rather than this broader behavioural
    disturbance.
  phenotype_term:
    preferred_term: Atypical behavior
    term:
      id: HP:0000708
      label: Atypical behavior
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Behavioral and psychiatric conditions reported in some affected individuals
      include autism spectrum disorder, schizophrenia, and behavioral
      abnormalities
    explanation: >-
      The chapter's own grouping, and the source of the OCCASIONAL band: it says
      these conditions are reported in some affected individuals rather than in
      most. The quoted sentence continues with a parenthetical naming aggression
      and self-injury, which is where this row's description comes from.
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We emphasize that renal disease, learning disability, behavioral
      abnormalities, epilepsy, autism, schizophrenia, structural brain
      abnormalities, facial dysmorphism, and joint laxity are features seen in
      both the 17q12 deletion syndrome and the reciprocal 17q12 duplication
      syndrome
    explanation: >-
      The cohort sentence that places behavioural abnormality in the duplication
      phenotype as well as the deletion's. It is the same sentence several other
      rows in this entry rest on.
- category: Behavioral
  name: Attention deficit hyperactivity disorder
  description: >-
    Attention deficit hyperactivity disorder, named in the neuropsychiatric
    spectrum reviews of the duplication and documented in individual carriers. No
    cohort reports a frequency for it, so none is assigned here.
  phenotype_term:
    preferred_term: Attention deficit hyperactivity disorder
    term:
      id: HP:0007018
      label: Attention deficit hyperactivity disorder
  evidence:
  - reference: PMID:38379631
    reference_title: "Complex neuropsychiatric presentation of 17q12 duplication syndrome: A case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: >-
      It varies from asymptomatic to neurodevelopmental disorders, including
      developmental delay, attention deficit hyperkinetic disorder, epilepsy,
      autism spectrum disorder, intellectual disabilities, behavioral problems
    explanation: >-
      Places attention deficit disorder in the duplication's phenotypic range.
      The sentence opens the case report's introduction and summarizes prior
      literature rather than this patient, which is what the BACKGROUND role
      records.
  - reference: PMID:41700275
    reference_title: Valproic Acid-Induced Pancreatitis in a Pediatric Patient With 17q12 Duplication Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The presence of a 17q12 duplication syndrome, in addition to diagnoses of
      ASD and ADHD, expands the spectrum of patients who may be at increased risk
      for this reaction.
    explanation: >-
      A single carrier who carries the diagnosis. The sentence is making a point
      about drug susceptibility rather than about phenotype frequency, so it
      documents co-occurrence in one patient and nothing more.
- category: Neurologic
  name: Seizure
  description: >-
    Epilepsy. The duplication's association with seizures was the first
    phenotypic signal reported for it, before the neurodevelopmental picture was
    described.
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  frequency: FREQUENT
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Seizures are present in 36%.
    explanation: >-
      The only numeric phenotype frequency GeneReviews gives for this
      duplication, and the basis for the FREQUENT band here. Nothing else in this
      entry has a comparable denominator.
  - reference: PMID:17924346
    reference_title: Recurrent reciprocal genomic rearrangements of 17q12 are associated with renal disease, diabetes, and epilepsy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We also identified the reciprocal duplication, which appears to be enriched
      in samples from patients with epilepsy.
    explanation: >-
      The original epilepsy association. Note the authors' own hedge, "appears to
      be enriched", which is why no frequency is assigned to this phenotype.
- category: Psychiatric
  name: Schizophrenia
  description: >-
    Increased schizophrenia risk. The Swedish national CNV study reported an odds
    ratio of about 4 for 17q12 duplication, which it describes as a novel
    association for this locus.
  phenotype_term:
    preferred_term: Schizophrenia
    term:
      id: HP:0100753
      label: Schizophrenia
  evidence:
  - reference: PMID:24776740
    reference_title: Copy number variation in schizophrenia in Sweden.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report a novel association for 17q12 duplications (odds ratio=4.16,
      P=0.018), previously associated with autism and mental retardation but not
      SCZ.
    explanation: >-
      The effect size and its p-value, from a case-control study of 4,719 cases
      and 5,917 controls. An odds ratio is a risk statement about carriers, not a
      frequency of schizophrenia among them, so no frequency band is assigned.
- category: Behavioral
  name: Tics
  description: >-
    Persistent tic disorder and Tourette syndrome. A meta-analysis of
    tic-disorder CNV studies found 17q12 duplication at genome-wide significance,
    which was a new association for the locus.
  phenotype_term:
    preferred_term: Tics
    term:
      id: HP:0100033
      label: Tics
  evidence:
  - reference: PMID:40894066
    reference_title: Persistent Tic Disorders Are Associated With 17q12 Duplications.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Additionally, a novel, genome-wide significant CNV locus for TS/PTD was
      discovered, involving duplications at 17q12 (hg19 chr17:34.8 - 36.2 Mb).
    explanation: >-
      The association and its genomic coordinates, from a meta-analysis of 5,725
      cases and 10,982 controls.
- category: Neurologic
  name: Abnormal brain morphology
  description: Structural brain abnormalities, shared with the deletion syndrome.
  phenotype_term:
    preferred_term: Abnormal brain morphology
    term:
      id: HP:0012443
      label: Abnormal brain morphology
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We emphasize that renal disease, learning disability, behavioral
      abnormalities, epilepsy, autism, schizophrenia, structural brain
      abnormalities, facial dysmorphism, and joint laxity are features seen in
      both the 17q12 deletion syndrome and the reciprocal 17q12 duplication
      syndrome
    explanation: Structural brain abnormality among the shared features.
- category: Craniofacial
  name: Abnormal facial shape
  description: Facial dysmorphism, shared with the deletion syndrome and not distinctive.
  phenotype_term:
    preferred_term: Abnormal facial shape
    term:
      id: HP:0001999
      label: Abnormal facial shape
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We emphasize that renal disease, learning disability, behavioral
      abnormalities, epilepsy, autism, schizophrenia, structural brain
      abnormalities, facial dysmorphism, and joint laxity are features seen in
      both the 17q12 deletion syndrome and the reciprocal 17q12 duplication
      syndrome
    explanation: Facial dysmorphism among the shared features.
- category: Musculoskeletal
  name: Joint hypermobility
  description: >-
    Joint laxity, shared with the deletion syndrome. The source's word is "joint
    laxity"; HPO retired its Joint laxity term (HP:0001388) in favour of Joint
    hypermobility, which is what this binds.
  phenotype_term:
    preferred_term: joint laxity
    term:
      id: HP:0001382
      label: Joint hypermobility
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We emphasize that renal disease, learning disability, behavioral
      abnormalities, epilepsy, autism, schizophrenia, structural brain
      abnormalities, facial dysmorphism, and joint laxity are features seen in
      both the 17q12 deletion syndrome and the reciprocal 17q12 duplication
      syndrome
    explanation: Joint laxity among the shared features.
- category: Renal
  name: Abnormality of the kidney
  description: >-
    Renal malformation, including bilateral hypoplastic kidneys with
    vesico-ureteric reflux and multicystic dysplastic kidney with a contralateral
    hyperechogenic kidney. This was initially thought to be a deletion-only
    feature.
  phenotype_term:
    preferred_term: Abnormality of the kidney
    term:
      id: HP:0000077
      label: Abnormality of the kidney
  evidence:
  - reference: PMID:21540130
    reference_title: A 17q12 chromosomal duplication associated with renal disease and esophageal atresia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report here two first-degree relatives carrying a 17q12 duplication and
      harboring various renal abnormalities (bilateral hypoplastic kidneys with
      vesico-ureteric reflux or multicystic dysplatic kidney with contralateral
      hyperechogenic kidney).
    explanation: >-
      The renal lesions in two genotyped duplication carriers, described
      individually rather than as a category.
- category: Gastrointestinal
  name: Esophageal atresia
  description: >-
    Esophageal atresia, identified at birth in one of the two reported
    duplication relatives and now listed among the features shared with the
    deletion.
  phenotype_term:
    preferred_term: Esophageal atresia
    term:
      id: HP:0002032
      label: Esophageal atresia
  evidence:
  - reference: PMID:21540130
    reference_title: A 17q12 chromosomal duplication associated with renal disease and esophageal atresia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Esophageal atresia (EA) type C was identified at birth in one patient while
      none had neurological disorder.
    explanation: >-
      The esophageal lesion, and with it the observation that these two carriers
      had no neurological disorder at all, which is the variable-expressivity
      point in its sharpest form.
- category: Gastrointestinal
  name: Duodenal atresia
  description: >-
    Duodenal atresia, presenting prenatally as the "double bubble" sign and now
    listed among the features shared with the deletion.
  phenotype_term:
    preferred_term: Duodenal atresia
    term:
      id: HP:0002247
      label: Duodenal atresia
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we extend the list of features seen in both patient categories to include
      strabismus, esophageal defects, and duodenal atresia.
    explanation: >-
      Adds duodenal atresia to the shared feature list. It is also the source for
      strabismus, which is curated separately below.
- category: Ophthalmologic
  name: Strabismus
  description: >-
    Strabismus, added by the Danish cohort to the list of features shared by the
    deletion and duplication.
  phenotype_term:
    preferred_term: Strabismus
    term:
      id: HP:0000486
      label: Strabismus
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we extend the list of features seen in both patient categories to include
      strabismus, esophageal defects, and duodenal atresia.
    explanation: Strabismus among the newly added shared features.
genetic:
- name: HNF1B
  gene_term:
    preferred_term: HNF1B
    term:
      id: hgnc:11630
      label: HNF1B
  relationship_type: CAUSATIVE
  notes: >-
    HNF1B is the gene the literature treats as the dosage-sensitive driver of the
    17q12 interval, and it is the gene whose point mutations and whole-gene
    deletion cause MODY5 and renal cystic disease. Its role in the duplication is
    an inference from that, plus the zebrafish overexpression result: no study has
    shown which interval gene produces which duplication phenotype. The
    relationship is recorded as CAUSATIVE because the duplication is causative and
    HNF1B is in it, not because HNF1B-specific causation has been demonstrated for
    the duplication phenotype.
  evidence:
  - reference: PMID:17924346
    reference_title: Recurrent reciprocal genomic rearrangements of 17q12 are associated with renal disease, diabetes, and epilepsy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      One of the microdeletions, identified in a fetus with multicystic dysplastic
      kidneys, encompasses the TCF2 gene on 17q12, previously shown to be mutated
      in maturity-onset diabetes, as well as in a subset of pediatric renal
      abnormalities.
    explanation: >-
      Establishes HNF1B (TCF2) as the gene of interest in the interval. Note it
      describes the deletion, which is exactly the inferential step this entry
      flags rather than hides.
- name: LHX1
  gene_term:
    preferred_term: LHX1
    term:
      id: hgnc:6593
      label: LHX1
  relationship_type: UNKNOWN
  notes: >-
    LHX1 is a LIM-homeobox transcription factor inside the duplicated interval and
    is named alongside HNF1B in every description of the region's gene content. No
    study attributes a specific duplication phenotype to LHX1 dosage, so the
    relationship is left UNKNOWN rather than asserted.
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The aberrations encompass the genes, HNF1B, LHX1, and ACACA, among others.
    explanation: >-
      Places LHX1 in the interval. That is the whole of what is established about
      its role here.
- name: ACACA
  gene_term:
    preferred_term: ACACA
    term:
      id: hgnc:84
      label: ACACA
  relationship_type: UNKNOWN
  notes: >-
    ACACA encodes acetyl-CoA carboxylase alpha and sits in the duplicated
    interval. It is the only interval gene for which a narrowing observation
    exists: one tic-disorder case carried a 110 kb duplication containing ACACA
    alone. That is a single case, and the odds ratio computed from it is
    correspondingly wide, so it is a lead about where the neuropsychiatric signal
    sits rather than a gene-disease assertion.
  evidence:
  - reference: PMID:40894066
    reference_title: Persistent Tic Disorders Are Associated With 17q12 Duplications.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Eight cases and one control carried the canonical ~1.4 Mb duplication at
      chr17:34.8 - 36.2 Mb, while one additional case had a smaller 110 kb
      duplication within this known CNV that included only one gene, ACACA
    explanation: >-
      The single-case narrowing observation, quoted with its denominator rather
      than only its odds ratio.
diagnosis:
- name: Chromosomal microarray analysis
  description: >-
    The duplication is about 1.4 Mb, below the resolution of a karyotype, so
    chromosomal microarray is the diagnostic test. Prenatally, SNP-array or
    CNV-seq on amniotic fluid is the equivalent. Parental testing follows,
    because inheritance from an apparently unaffected parent is common and
    changes the recurrence risk.
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      The diagnosis is established in a proband by detection of the
      1.4-megabase heterozygous recurrent duplication at chromosome 17q12 by
      chromosomal microarray testing or other genomic methods.
    explanation: >-
      The GeneReviews diagnostic criterion, which fixes both the size of the
      canonical duplication and the test that establishes it.
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      17q12 deletions and duplications are two distinct, recurrent chromosomal
      aberrations usually diagnosed by chromosomal microarray analysis (CMA).
    explanation: Names the diagnostic modality for both rearrangements.
  - reference: PMID:39433644
    reference_title: "Prenatal diagnosis, ultrasound findings, and pregnancy outcome of 17q12 deletion and duplication syndromes: a retrospective case series."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Peripheral blood from the parents was extracted to determine whether the
      CNVs in the fetuses were inherited or de novo.
    explanation: >-
      The parental testing step, as performed in the prenatal series. It is what
      converts a fetal finding into a recurrence risk.
differential_diagnoses:
- name: Chromosome 17q12 deletion syndrome
  description: >-
    The reciprocal rearrangement at the same breakpoints. It shares renal
    disease, learning disability, behavioural abnormality, epilepsy, autism,
    schizophrenia, structural brain anomalies, facial dysmorphism and joint
    laxity with the duplication, but its renal and diabetes phenotype (RCAD /
    MODY5) is far more consistent. Microarray distinguishes them immediately;
    clinical features do not.
  distinguishing_features:
  - Delayed language development, learning disability, kidney involvement and eye
    dysmorphism with strabismus are the features most consistently shared among
    deletion patients.
  - The duplication group is characterised instead by an extremely wide and less
    predictable spectrum, weighted toward neurodevelopmental and psychiatric
    features rather than renal disease and diabetes.
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Delayed language development, learning disability, kidney involvement, and
      eye dysmorphism and strabismus were the most consistently shared features
      among patients with 17q12 deletion.
    explanation: >-
      The deletion's own consistent-feature list, which is what the duplication
      has to be distinguished from.
treatments:
- name: Multidisciplinary supportive management
  description: >-
    There is no disease-specific or curative treatment. Management is
    symptom-directed across developmental, psychiatric, renal, cardiac and
    surgical domains as each applies to the individual.
  therapeutic_modality: OTHER
  treatment_term:
    preferred_term: multidisciplinary supportive care
    term:
      id: NCIT:C15747
      label: Supportive Care
  target_mechanisms:
  - target: Neurodevelopmental and Neuropsychiatric Dysfunction
    description: >-
      Addresses the functional consequences of the neurodevelopmental phenotype.
      Nothing available modifies the gene dosage that causes it.
  evidence:
  - reference: PMID:38379631
    reference_title: "Complex neuropsychiatric presentation of 17q12 duplication syndrome: A case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Treatment involves a multidisciplinary approach
    explanation: >-
      The management principle. It is a case report's framing rather than a
      guideline, which is the strongest statement available for this disorder.
- name: Developmental, psychological and seizure surveillance
  description: >-
    GeneReviews specifies regular assessment of psychomotor development for every
    child with the duplication, psychological evaluation in both affected
    children and adults, monitoring for new-onset seizures, growth and
    nutritional assessment, and assessment of family needs at each visit. The
    adult psychological arm is the part most easily dropped, and it is the part
    the schizophrenia and tic associations argue for.
  therapeutic_modality: OTHER
  treatment_term:
    preferred_term: clinical surveillance
    term:
      id: NCIT:C124351
      label: Clinical Evaluation
  target_mechanisms:
  - target: Neurodevelopmental and Neuropsychiatric Dysfunction
    description: >-
      Detects developmental, psychiatric and seizure manifestations early enough
      to intervene. It does not modify the underlying dosage imbalance.
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Regular assessment of psychomotor development is recommended for all
      children with the 17q12 recurrent duplication as well as psychological
      evaluation in both affected children and adults. Monitor for new-onset
      seizures, growth and nutritional assessment, and assessment of family needs
      at each visit.
    explanation: The GeneReviews surveillance schedule for this duplication.
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Presymptomatic diagnosis and treatment is warranted in at-risk relatives to
      identify as early as possible those who would benefit from close
      assessment/monitoring of developmental milestones in childhood or
      psychological assessment/intervention through adulthood.
    explanation: >-
      The recommendation to test and follow at-risk relatives, which is what
      makes cascade testing an intervention rather than only information.
- name: Genetic counselling and cascade testing
  description: >-
    Counselling is the intervention with the most to offer here and the hardest
    to deliver, because penetrance is incomplete, expressivity is wide, and the
    burden observed depends on whether the family was ascertained on the
    duplication or on a phenotype. The Danish cohort states that difference
    explicitly and offers it as material for prenatal counselling.
  therapeutic_modality: OTHER
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  target_mechanisms:
  - target: NAHR Between 17q12 Segmental Duplications
    description: >-
      Counselling acts on the lesion only in the reproductive sense: it addresses
      the recurrence risk of the non-allelic homologous recombination event and
      the transmission of an inherited duplication. It changes nothing downstream
      of the lesion in a person who already carries it.
  - target: Neurodevelopmental and Neuropsychiatric Dysfunction
    description: >-
      Cascade testing identifies at-risk relatives early enough for
      developmental monitoring in childhood and psychological assessment in
      adulthood, which is the chapter's stated reason for testing them. The
      benefit is earlier detection, not modification of the phenotype.
  evidence:
  - reference: PMID:27409573
    reference_title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Assessing index patients and non-index patients separately, our
      observations illustrate that an overall milder disease burden is seen, in
      particular in patients with 17q12 duplications who are ascertained on the
      duplication rather than the phenotype. This evidence may be useful in
      prenatal counseling.
    explanation: >-
      The ascertainment effect and the authors' own statement of its counselling
      use. This is the single most important sentence for anyone applying this
      entry's frequencies to a newly ascertained carrier.
  - reference: PMID:39286125
    reference_title: Prenatal diagnosis of 17q12 copy number variants in fetuses via chromosomal microarray analysis - A retrospective cohort study and literature review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: >-
      17q12 copy number variants (CNVs) have variable presentations and
      incomplete penetrance, challenging prenatal counseling and management
    explanation: >-
      States the counselling problem directly. It opens the paper's structured
      PURPOSE section, so it frames the study rather than reporting its result.
- name: Neurologist-managed antiseizure therapy
  description: >-
    GeneReviews directs that seizures be managed by a neurologist using standard
    practice; nothing about the duplication changes which antiseizure medicines
    are indicated. One caution is specific enough to record: a 14-year-old
    carrier on valproate monotherapy at therapeutic dosing, with no other risk
    factor, developed acute pancreatitis that resolved on discontinuation and was
    rated probable on the Naranjo scale. The authors state this genetic
    background had not previously been reported with valproate pancreatitis and
    that more evidence is needed, so this is a single-case signal rather than an
    established contraindication, and it is recorded that way here.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: antiseizure pharmacotherapy
    term:
      id: NCIT:C64172
      label: Anticonvulsant Therapy
    therapeutic_agent:
    - preferred_term: valproic acid
      term:
        id: CHEBI:39867
        label: valproic acid
  target_mechanisms:
  - target: Seizure
    description: >-
      Suppresses the seizures that are present in 36% of carriers. It does not
      act on the dosage imbalance upstream of them.
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Seizures should be managed by a neurologist using standard practice.
    explanation: >-
      The management instruction. It is deliberately unspecific about agent,
      which is why the valproate caution below is worth recording separately.
  - reference: PMID:41700275
    reference_title: Valproic Acid-Induced Pancreatitis in a Pediatric Patient With 17q12 Duplication Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This adverse effect occurred with VPA monotherapy at therapeutic dosing in
      the absence of risk factors, in the setting of 17q12 duplication syndrome,
      ADHD, and ASD.
    explanation: >-
      The observation itself, with the two features that make it worth recording:
      monotherapy and no other risk factor. Polypharmacy is the usual setting for
      this adverse reaction, so its absence is what leaves the duplication as a
      candidate.
  - reference: PMID:41700275
    reference_title: Valproic Acid-Induced Pancreatitis in a Pediatric Patient With 17q12 Duplication Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Presence of a 17q12 duplication syndrome in association with VPA-induced
      pancreatitis has not been previously described, possibly suggesting a
      previously unknown susceptibility, although more evidence is needed.
    explanation: >-
      The authors' own limit on the claim, quoted so that this treatment record
      cannot be read as asserting a susceptibility. One case with no rechallenge
      cannot establish one, and no pathophysiology node is created for it.
- name: Feeding therapy
  description: >-
    Feeding therapy as needed, one of the GeneReviews treatment-of-manifestations
    items. It follows from the hypotonia rather than from any gene-specific
    mechanism, and the chapter gives no frequency for feeding difficulty in this
    duplication.
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: feeding therapy
    term:
      id: NCIT:C156237
      label: Swallowing Therapy
  target_mechanisms:
  - target: Hypotonia
    description: >-
      Addresses the oral-motor consequence of the hypotonia. It does not treat
      the hypotonia itself.
  evidence:
  - reference: PMID:26925472
    reference_title: 17q12 Recurrent Duplication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      Seizures should be managed by a neurologist using standard practice.
      Feeding therapy as needed.
    explanation: >-
      "Feeding therapy as needed" is the chapter's whole statement on it, and is
      quoted with the sentence before it because four words cannot evidence
      anything on their own. Nothing more specific is published for this
      duplication, and the terseness is the reason this row carries no frequency
      and no protocol.
discussions:
- discussion_id: gap_17q12dup_which_gene_carries_the_neuropsychiatric_signal
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    Which gene in the 17q12 interval carries the neurodevelopmental and
    neuropsychiatric signal of the duplication?
  attaches_to:
  - "pathophysiology#Increased 17q12 Gene Dosage"
  - "genetic#ACACA"
  rationale: >-
    Every mechanistic account of this syndrome routes through HNF1B, and the
    reason is historical rather than experimental: HNF1B is the gene whose point
    mutations cause MODY5 and renal cystic disease, so it was the gene everyone
    already knew about when the CNV was found. The only evidence that actually
    discriminates between interval genes points elsewhere, to a single
    tic-disorder case with a 110 kb duplication containing ACACA alone. One case
    cannot settle it, and the confidence interval on its odds ratio will be very
    wide, but it is the only observation in the literature that narrows the
    interval at all, and it does not narrow it onto HNF1B. The zebrafish
    overexpression result, which is the strongest mechanistic evidence for the
    gain direction, tests the HNF1B ortholog and so cannot distinguish the two
    hypotheses either. The stake is practical: if the neuropsychiatric phenotype
    is ACACA-driven, small intragenic duplications reported by microarray would
    need different interpretation from the canonical CNV.
  proposed_experiments:
  - experiment_id: exp_17q12dup_atypical_cnv_breakpoint_series
    name: Phenotype series of atypical, non-canonical 17q12 duplications
    description: >-
      Assemble carriers of 17q12 duplications whose breakpoints do not match the
      canonical NAHR interval, from clinical microarray archives, and compare
      neurodevelopmental and psychiatric outcome by which interval genes each
      duplication contains. Atypical breakpoints are the only natural experiment
      available for separating the interval's genes in humans.
- discussion_id: gap_17q12dup_penetrance_denominator
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    What is the penetrance of the 17q12 duplication in an unselected carrier, as
    opposed to in a carrier ascertained through a clinic?
  attaches_to:
  - "prevalence#Danish national 17q12 cohort, phenotyped patients"
  rationale: >-
    Almost everything known about this syndrome's frequency comes from series
    that recruited on a phenotype, whether developmental delay, schizophrenia,
    tics or a fetal ultrasound anomaly, and the one cohort that separated index
    from non-index patients found a milder burden in those ascertained on the
    duplication. Newborn CNV screening gives a clean prevalence for recurrent NDD
    CNVs as a class, but not a duplication-specific penetrance, and the two
    published case-control odds ratios (schizophrenia, tics) are risk ratios
    rather than penetrance. The result is that a carrier found incidentally, for
    example on a prenatal microarray done for another indication, cannot be given
    a numeric risk for any of the features in this entry. That is the situation
    the prenatal literature describes as challenging counselling, and it is a gap
    in evidence rather than in mechanism.
  proposed_experiments:
  - experiment_id: exp_17q12dup_biobank_recall
    name: Phenotype recall of 17q12 duplication carriers found in population biobanks
    description: >-
      Identify 17q12 duplication carriers in unselected population biobanks with
      linked health records, and estimate the frequency of intellectual
      disability, autism, epilepsy, tic disorder, schizophrenia and renal anomaly
      among them without conditioning on any of those phenotypes.
notes: >-
  Scope and lump/split. This is the duplication, and it is a separate Disease
  entry from Chromosome_17q12_Deletion_Syndrome rather than a subtype row on it.
  The two lesions share breakpoints and a gene list, but the Danish national
  cohort reports different consistent features for each, and the deletion's
  renal-and-diabetes phenotype is not the duplication's. MONDO:0013796 was bound
  nowhere in kb/ before this entry. The deletion entry is not edited by this
  change; cross-linking the two is a follow-on.

  Whose cohort a number comes from. Three different denominators appear in this
  entry and they are not interchangeable: the Danish national cohort (26
  phenotyped duplication patients, a mix of index and family members), the
  Chinese prenatal series (seven duplication fetuses, all ascertained on an
  ultrasound anomaly), and the Norwegian newborn trios (unselected, but reporting
  the 26 recurrent NDD CNVs as a class rather than this one). Each record says
  which it is. The schema has no structured place for that, so it lives in
  descriptions and notes and is not queryable, which matters more here than in
  most entries, because the whole clinical difficulty of this syndrome is that
  its numbers depend on how the carrier was found.

  Frequency bands, and where they stop. A band is assigned only where a source
  states how many carriers have the feature, or uses a quantifier the HPO bands
  are defined against. FREQUENT covers learning disability, language delay and
  motor delay, which the national cohort names as characteristic of the
  duplication group, plus hypotonia and seizures, for which GeneReviews gives
  "most affected individuals" and 36% respectively. OCCASIONAL covers the
  features the chapter reports "in some affected individuals": short stature,
  cardiac abnormality and behavioural abnormality. Everything else carries no
  frequency at all, and that is deliberate rather than incomplete. The
  schizophrenia and tic findings are odds ratios from case-control studies, which
  say how much more likely a carrier is to have the trait, not how many carriers
  do; the malformations come from a seven-fetus prenatal series ascertained on
  the malformations themselves; and attention deficit disorder appears only in
  review lists and individual case reports. Converting any of those into an HPO
  frequency band would manufacture a number the literature does not contain.

  What the mechanism does and does not claim. The pathograph asserts dosage
  imbalance of the interval, not HNF1B-specific causation. Only one experiment
  anywhere tests the gain direction, zebrafish vhnf1 overexpression expanding the
  hindbrain valentino domain, and it is graded MODEL_ORGANISM. Everything between
  that and the human phenotype is INDIRECT_UNKNOWN_INTERMEDIATES, because nothing
  published fills it in. Attributing the neurodevelopmental phenotype to HNF1B
  specifically would be the most natural-sounding claim in the entry and is not
  supported; the competing ACACA observation is curated as a knowledge gap
  instead.

  Deep research. One OpenScientist run, committed. `just preflight-dr` returned
  SKIP, which means unchecked, because MONDO records no causal gene for
  MONDO:0013796. Manual fallback: HNF1B 33 mentions, LHX1 13, ACACA 12, against 3
  for ARX, which appears only as a co-occurring variant in one family. Right
  entity. The report's own term validation flagged four NCIT identifiers whose
  labels name unrelated concepts (C15318 offered as "Rehabilitation Therapy" but
  named Reproducibility; C15328 as "Behavioral Therapy" but named Splenectomy;
  C15311 as "Monitoring" but named Quality Control; C265 as "Antipsychotic Agent"
  but named Antidepressant Agent). None of those is bound in this entry. Its
  reference validation flagged two quotes as not found in their sources; both
  turned out to be truncations of real sentences rather than inventions, and
  where this entry quotes those papers it quotes the full sentence.

  A note on the report's own validation sections. The run wrote neither the
  reference_validation frontmatter block nor the Reference Validation and Term
  Validation sections, although the validators demonstrably ran: their warnings
  appear in the run log. Both sections were recovered afterwards with
  `just validate-research-reference`, and the committed report carries them. It
  matters because a reader of the report as first written would have had no way
  to know two quotes had failed.

  What is deliberately absent. No datasets: block, because no dataset specific to
  the duplication was identified, and searching the interval genes returns the
  much larger HNF1B renal and diabetes literature, which is the reciprocal
  deletion's disease. No clinical_trials: block; none found. No environmental:
  block; this is a genomic disorder with no established environmental
  contributor. No animal_models: block; the zebrafish vhnf1 work is curated as
  evidence on the patterning node, but it is a study of the ortholog's function
  rather than a model of this syndrome, and recording it as an animal model of
  17q12 duplication would overstate what was done. GeneReviews. PMID:26925472, 17q12 Recurrent Duplication, is the
  baseline chapter, is tagged in references:, and is mined here for the de novo
  fraction, the diagnostic criterion, the seizure frequency, five additional
  phenotypes and the surveillance schedule.

  How it was found, and what that says about the run. The OpenScientist report
  does not cite the chapter, and neither did this entry's first draft, which
  stated in these notes that no GeneReviews chapter existed. `just
  check-genereviews` found it, but only on the second run: the first run was
  against a draft that had a name and a MONDO term and no synonyms, and the
  chapter matches on the synonym "17q12 recurrent duplication" rather than on the
  entry name. So the order matters. Running the check before synonyms are written
  produces a confident NO_CHAPTER for an entry that has one. Two claims in the
  first draft were wrong as a result and are corrected above: the de novo
  fraction (the class-wide 34% was used where the locus-specific figure is about
  10%) and the absence of a numeric seizure frequency (the chapter gives 36%).

  Review round 1. Five things changed. Two behavioural rows were missing and are
  added: atypical behavior, which the entry was already quoting in the autism
  row's snippet without modelling, and attention deficit hyperactivity disorder.
  The valproate case report is now a treatment record rather than an
  undispositioned research finding; it is deliberately not a pathophysiology
  node, because one case with no rechallenge does not establish a susceptibility
  and the authors say so in the sentence quoted against it. Variable Organ
  Malformation contradicted itself, naming cardiac malformation in its
  description and strabismus in its evidence while wiring neither; both are now
  wired and the description says why strabismus sits in that branch. Hypotonia
  was an orphan row and is now downstream of the neurodevelopmental node. Two
  GeneReviews management items, neurologist-managed seizures and feeding therapy,
  were unmodelled and are added. The surveillance treatment bound
  NCIT:C49236 Therapeutic Procedure, which has no precedent in kb/ for a
  monitoring activity; NCIT:C15719 Surveillance is the obvious replacement but is
  not reachable from NCIT:C25218 and fails the TreatmentActionTerm enum, so the
  binding is NCIT:C124351 Clinical Evaluation.
references:
- reference: PMID:26925472
  title: 17q12 Recurrent Duplication.
  tags:
  - GeneReviews
- reference: PMID:17924346
  title: Recurrent reciprocal genomic rearrangements of 17q12 are associated with renal disease, diabetes, and epilepsy.
- reference: PMID:27409573
  title: 17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
- reference: PMID:30134084
  title: "Chromosome 17q12 duplications: Further delineation of the range of psychiatric and clinical phenotypes."
- reference: PMID:40894066
  title: Persistent Tic Disorders Are Associated With 17q12 Duplications.
- reference: PMID:11731484
  title: "vhnf1, the MODY5 and familial GCKD-associated gene, regulates regional specification of the zebrafish gut, pronephros, and hindbrain."
- reference: PMID:41700275
  title: Valproic Acid-Induced Pancreatitis in a Pediatric Patient With 17q12 Duplication Syndrome.
datasets: []
📚

References & Deep Research

References

7
PMID:26925472
17q12 Recurrent Duplication.
No top-level findings curated for this source.
PMID:17924346
Recurrent reciprocal genomic rearrangements of 17q12 are associated with renal disease, diabetes, and epilepsy.
No top-level findings curated for this source.
PMID:27409573
17q12 deletion and duplication syndrome in Denmark-A clinical cohort of 38 patients and review of the literature.
No top-level findings curated for this source.
PMID:30134084
Chromosome 17q12 duplications: Further delineation of the range of psychiatric and clinical phenotypes.
No top-level findings curated for this source.
PMID:40894066
Persistent Tic Disorders Are Associated With 17q12 Duplications.
No top-level findings curated for this source.
PMID:11731484
vhnf1, the MODY5 and familial GCKD-associated gene, regulates regional specification of the zebrafish gut, pronephros, and hindbrain.
No top-level findings curated for this source.
PMID:41700275
Valproic Acid-Induced Pancreatitis in a Pediatric Patient With 17q12 Duplication Syndrome.
No top-level findings curated for this source.

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (2)

Record notes

Scope and lump/split. This is the duplication, and it is a separate Disease entry from Chromosome_17q12_Deletion_Syndrome rather than a subtype row on it. The two lesions share breakpoints and a gene list, but the Danish national cohort reports different consistent features for each, and the deletion's renal-and-diabetes phenotype is not the duplication's. MONDO:0013796 was bound nowhere in kb/ before this entry. The deletion entry is not edited by this change; cross-linking the two is a follow-on. Whose cohort a number comes from. Three different denominators appear in this entry and they are not interchangeable: the Danish national cohort (26 phenotyped duplication patients, a mix of index and family members), the Chinese prenatal series (seven duplication fetuses, all ascertained on an ultrasound anomaly), and the Norwegian newborn trios (unselected, but reporting the 26 recurrent NDD CNVs as a class rather than this one). Each record says which it is. The schema has no structured place for that, so it lives in descriptions and notes and is not queryable, which matters more here than in most entries, because the whole clinical difficulty of this syndrome is that its numbers depend on how the carrier was found. Frequency bands, and where they stop. A band is assigned only where a source states how many carriers have the feature, or uses a quantifier the HPO bands are defined against. FREQUENT covers learning disability, language delay and motor delay, which the national cohort names as characteristic of the duplication group, plus hypotonia and seizures, for which GeneReviews gives "most affected individuals" and 36% respectively. OCCASIONAL covers the features the chapter reports "in some affected individuals": short stature, cardiac abnormality and behavioural abnormality. Everything else carries no frequency at all, and that is deliberate rather than incomplete. The schizophrenia and tic findings are odds ratios from case-control studies, which say how much more likely a carrier is to have the trait, not how many carriers do; the malformations come from a seven-fetus prenatal series ascertained on the malformations themselves; and attention deficit disorder appears only in review lists and individual case reports. Converting any of those into an HPO frequency band would manufacture a number the literature does not contain. What the mechanism does and does not claim. The pathograph asserts dosage imbalance of the interval, not HNF1B-specific causation. Only one experiment anywhere tests the gain direction, zebrafish vhnf1 overexpression expanding the hindbrain valentino domain, and it is graded MODEL_ORGANISM. Everything between that and the human phenotype is INDIRECT_UNKNOWN_INTERMEDIATES, because nothing published fills it in. Attributing the neurodevelopmental phenotype to HNF1B specifically would be the most natural-sounding claim in the entry and is not supported; the competing ACACA observation is curated as a knowledge gap instead. Deep research. One OpenScientist run, committed. `just preflight-dr` returned SKIP, which means unchecked, because MONDO records no causal gene for MONDO:0013796. Manual fallback: HNF1B 33 mentions, LHX1 13, ACACA 12, against 3 for ARX, which appears only as a co-occurring variant in one family. Right entity. The report's own term validation flagged four NCIT identifiers whose labels name unrelated concepts (C15318 offered as "Rehabilitation Therapy" but named Reproducibility; C15328 as "Behavioral Therapy" but named Splenectomy; C15311 as "Monitoring" but named Quality Control; C265 as "Antipsychotic Agent" but named Antidepressant Agent). None of those is bound in this entry. Its reference validation flagged two quotes as not found in their sources; both turned out to be truncations of real sentences rather than inventions, and where this entry quotes those papers it quotes the full sentence. A note on the report's own validation sections. The run wrote neither the reference_validation frontmatter block nor the Reference Validation and Term Validation sections, although the validators demonstrably ran: their warnings appear in the run log. Both sections were recovered afterwards with `just validate-research-reference`, and the committed report carries them. It matters because a reader of the report as first written would have had no way to know two quotes had failed. What is deliberately absent. No datasets: block, because no dataset specific to the duplication was identified, and searching the interval genes returns the much larger HNF1B renal and diabetes literature, which is the reciprocal deletion's disease. No clinical_trials: block; none found. No environmental: block; this is a genomic disorder with no established environmental contributor. No animal_models: block; the zebrafish vhnf1 work is curated as evidence on the patterning node, but it is a study of the ortholog's function rather than a model of this syndrome, and recording it as an animal model of 17q12 duplication would overstate what was done. GeneReviews. PMID:26925472, 17q12 Recurrent Duplication, is the baseline chapter, is tagged in references:, and is mined here for the de novo fraction, the diagnostic criterion, the seizure frequency, five additional phenotypes and the surveillance schedule. How it was found, and what that says about the run. The OpenScientist report does not cite the chapter, and neither did this entry's first draft, which stated in these notes that no GeneReviews chapter existed. `just check-genereviews` found it, but only on the second run: the first run was against a draft that had a name and a MONDO term and no synonyms, and the chapter matches on the synonym "17q12 recurrent duplication" rather than on the entry name. So the order matters. Running the check before synonyms are written produces a confident NO_CHAPTER for an entry that has one. Two claims in the first draft were wrong as a result and are corrected above: the de novo fraction (the class-wide 34% was used where the locus-specific figure is about 10%) and the absence of a numeric seizure frequency (the chapter gives 36%). Review round 1. Five things changed. Two behavioural rows were missing and are added: atypical behavior, which the entry was already quoting in the autism row's snippet without modelling, and attention deficit hyperactivity disorder. The valproate case report is now a treatment record rather than an undispositioned research finding; it is deliberately not a pathophysiology node, because one case with no rechallenge does not establish a susceptibility and the authors say so in the sentence quoted against it. Variable Organ Malformation contradicted itself, naming cardiac malformation in its description and strabismus in its evidence while wiring neither; both are now wired and the description says why strabismus sits in that branch. Hypotonia was an orphan row and is now downstream of the neurodevelopmental node. Two GeneReviews management items, neurologist-managed seizures and feeding therapy, were unmodelled and are added. The surveillance treatment bound NCIT:C49236 Therapeutic Procedure, which has no precedent in kb/ for a monitoring activity; NCIT:C15719 Surveillance is the obvious replacement but is not reachable from NCIT:C25218 and fails the TreatmentActionTerm enum, so the binding is NCIT:C124351 Clinical Evaluation.

Create: Chromosome_17q12_Duplication_Syndrome (MONDO:0013796) · 2026-09-17T16:53:38Z · View source

De novo curation of MONDO:0013796, the recurrent 17q12 copy-number gain, as a separate Disease entry from the existing Chromosome_17q12_Deletion_Syndrome. Deep research: one OpenScientist run (research/Chromosome_17q12_Duplication_Syndrome-deep-research-openscientist.md). Two process findings are recorded in the entry notes and are the reason several draft claims changed. First, that run wrote neither the reference_validation frontmatter block nor the Reference Validation and Term Validation sections although the validators demonstrably ran, since their warnings appear in the run log; both sections were recovered with just validate-research-reference and the committed report carries them. Second, just check-genereviews reported NO_CHAPTER when run against the draft that had no synonyms, and UNTAGGED_CHAPTER once synonyms were added, surfacing PMID:26925472 '17q12 Recurrent Duplication' which the deep-research report never cites. Two claims in the first draft were wrong as a result and were corrected: the de novo fraction (the class-wide 34 percent from newborn trios was used where the chapter gives about 10 percent for this locus) and the absence of a seizure frequency (the chapter gives 36 percent). The chapter is now tagged and supplies five further phenotypes, the diagnostic criterion and the surveillance schedule. The report's term validation flagged four NCIT identifiers whose labels name unrelated concepts (C15318, C15328, C15311, C265); none is bound. preflight-dr returned SKIP because MONDO records no causal gene for this term; manual fallback gene counts are HNF1B 33, LHX1 13, ACACA 12. Validation run in the worktree: just validate 51/51 snippets verified, validate-terms, check-entity-refs, check-causal-targets, check-qualifier-terms, check-duplicate-keys, check-genereviews TAGGED - all clean.

OpenScientist ▸
Chromosome 17q12 Duplication Syndrome — Comprehensive Disease Characterization Report
openscientist-autonomous 26 citations 2026-09-17T16:32:56.132137

Chromosome 17q12 Duplication Syndrome — Comprehensive Disease Characterization Report

Target Disease: Chromosome 17q12 Duplication Syndrome MONDO ID: MONDO:0013796 Category: Mendelian (recurrent genomic/copy-number disorder) Report basis: 11 confirmed findings, 37 primary papers reviewed over 5 iterations

Summary

Chromosome 17q12 duplication syndrome is a rare, autosomal-dominant genomic (copy-number) disorder caused by a recurrent ~1.4–1.5 Mb copy-number gain at chromosome band 17q12 (hg19 chr17:~34.8–36.2 Mb). The region is flanked by segmental duplications that predispose it to non-allelic homologous recombination (NAHR), generating both this duplication and its reciprocal deletion. The duplicated interval spans roughly 15 OMIM genes, chief among them the dosage-sensitive transcription factor HNF1B (hepatocyte nuclear factor 1 beta), together with LHX1 and ACACA. The disorder was first described alongside its reciprocal deletion in 2007 as "the first example of a recurrent genomic disorder associated with diabetes" (PMID: 17924346).

Clinically, the duplication produces a highly variable, incompletely penetrant, predominantly neurodevelopmental/neuropsychiatric phenotype. Reported features include a variable degree of intellectual disability/learning disability, delayed speech and language, delayed motor milestones, autism spectrum disorder, schizophrenia (odds ratio ≈ 4), epilepsy, ADHD, and — established more recently — tics and Tourette/persistent tic disorder (a genome-wide significant association). Because penetrance is incomplete and expressivity is wide, the duplication is frequently inherited from a mildly-affected or apparently unaffected parent. Congenital malformations are less consistent than in the reciprocal deletion but include prenatal duodenal atresia ("double bubble" sign), cardiac malformations (including tetralogy of Fallot), growth anomalies, and variable renal and esophageal anomalies.

Diagnosis rests on chromosomal microarray analysis (CMA) — the sub-microscopic (~1.4 Mb) CNV is invisible to standard karyotyping — with prenatal detection via CMA/CNV-seq on amniotic fluid, usually prompted by fetal ultrasound anomalies. Parental testing is essential given frequent inheritance. There is no curative or disease-specific therapy; management is supportive, symptom-directed, and multidisciplinary, with a notable pharmacovigilance caution against valproate given documented valproate-induced pancreatitis in this population and the syndrome's underlying pancreatic/metabolic susceptibility. Short-term prognosis appears generally favorable. The leading mechanistic hypothesis is HNF1B gene-dosage imbalance; a zebrafish ortholog (vhnf1) is dosage-sensitive in both loss- and gain-of-function directions and, when overexpressed, perturbs hindbrain patterning — supporting a gain-of-dosage mechanism relevant to the CNS phenotype.

Section 1 — Disease Information

Overview. 17q12 duplication syndrome is a recurrent contiguous-gene copy-number gain disorder. It is the reciprocal counterpart of the better-characterized 17q12 deletion syndrome (Renal Cysts and Diabetes syndrome, RCAD/MODY5). Whereas the deletion produces a relatively specific renal-and-diabetes phenotype, the duplication produces a less specific, primarily neurodevelopmental/neuropsychiatric phenotype with wide expressivity and incomplete penetrance (PMID: 36548033; PMID: 27409573).

Key identifiers:

Resource Identifier
MONDO MONDO:0013796
Cytogenetic locus 17q12 (hg19 chr17:~34.8–36.2 Mb)
Core gene HNF1B (TCF2), OMIM 189907, HGNC:11630
Related deletion syndrome 17q12 deletion / RCAD (OMIM 137920)

Synonyms / alternative names: Chromosome 17q12 microduplication syndrome; 17q12 recurrent duplication; dup(17)(q12); reciprocal duplication of the 17q12 region.

Data provenance: The knowledge base for this disorder is drawn primarily from aggregated disease-level resources — case series, prenatal CMA cohorts, psychiatric CNV cohorts, and individual case reports — rather than a single EHR-derived individual-patient dataset. Evidence spans human clinical case series (majority), plus supporting model-organism (zebrafish, mouse) and in vitro data for mechanism.

Section 2 — Etiology

Primary cause (genetic). The disorder is caused by a recurrent ~1.4–1.5 Mb duplication at 17q12 arising via NAHR between flanking segmental duplications (Finding F001). Mefford et al. 2007 first described the reciprocal rearrangements and noted the duplication "appears to be enriched in samples from patients with epilepsy" (PMID: 17924346). The recurrent aberrations "encompass the genes, HNF1B, LHX1, and ACACA, among others" (PMID: 27409573).

Genetic risk factors. The duplication itself is the causal lesion; the dosage-sensitive driver is HNF1B (Finding F005). No independent susceptibility loci are established as necessary for expression, but variable expressivity and incomplete penetrance imply the action of modifier alleles and/or second genetic hits. Co-occurrence with independent pathogenic variants has been documented and can complicate the phenotype (e.g., co-inheritance with an ARX nonsense variant PMID: 32519823; with a CCDC103 PCD mutation PMID: 26123568; a sibling pair with reciprocal 16p11.2 deletion and 17q12 duplication PMID: 34538867) — illustrating that a "second hit" may modulate outcome.

Environmental risk factors / protective factors. None established. As a Mendelian CNV disorder, there are no proven environmental causes, lifestyle risk factors, protective variants, or gene–environment interactions specific to disease occurrence. This is a genuine knowledge gap rather than a negative finding. (Advanced parental age is not associated with higher recurrent-CNV yield; in one prenatal cohort advanced maternal age carried a lower incidence, PMID: 38081620.)

Section 3 — Phenotypes

The duplication phenotype is dominated by neurodevelopmental and neuropsychiatric features, with variable congenital malformations (Findings F002, F004, F007, F008). Rasmussen et al. described "an extremely wide phenotypic spectrum, including a variable degree of learning disabilities, delayed language development, delayed motor milestones, and a broad range of psychiatric and neurological features" (PMID: 27409573).

Phenotype Type HPO suggestion Onset Frequency / notes
Intellectual disability / learning disability cognitive HP:0001249 childhood Common; IQ range reported 52–99 (PMID: 30134084)
Delayed speech and language development neurodevelopmental HP:0000750 childhood Common (PMID: 27409573)
Motor delay neurodevelopmental HP:0001270 infancy/childhood Common
Autism spectrum disorder behavioral HP:0000717 childhood Recurrent (PMID: 22488896; PMID: 34538867)
Schizophrenia psychiatric HP:0100753 adolescence/adult OR ≈ 4.16 (P=0.018) (PMID: 24776740)
Epilepsy / seizures neurological HP:0001250 variable Duplication "enriched in patients with epilepsy" (PMID: 17924346)
ADHD / behavioral abnormalities behavioral HP:0007018 / HP:0000708 childhood Common
Tics / Tourette / persistent tic disorder behavioral HP:0100033 childhood Genome-wide significant association (PMID: 40894066)
Structural brain abnormalities CNS malformation HP:0012443 congenital Reported in shared del/dup features
Facial dysmorphism physical HP:0001999 congenital Reported
Joint laxity connective tissue HP:0001388 congenital Reported
Renal anomalies renal HP:0000077 congenital Variable (less consistent than deletion) (PMID: 21540130)
Duodenal atresia ("double bubble") GI malformation HP:0002247 prenatal Prenatal duplication feature (PMID: 33678321)
Cardiac malformation (incl. tetralogy of Fallot) cardiovascular HP:0001636 / HP:0001631 prenatal 4/7 (57%) in one prenatal series (PMID: 39433644)
Esophageal atresia GI malformation HP:0002032 prenatal Reported (PMID: 21540130)
Growth anomalies growth HP:0001507 prenatal/childhood Prenatal duplication feature (PMID: 33678321)

Characteristics. Severity is variable (mild to severe), progression is generally stable rather than degenerative (neurodevelopmental features are static, though psychiatric features such as schizophrenia and tics have their own developmental onset windows). Age of onset ranges from congenital/prenatal (malformations) to childhood (neurodevelopmental) to adolescence/adulthood (schizophrenia).

Quality of life impact. No disease-specific EQ-5D/SF-36/PROMIS data were identified. Impact is inferred to be driven by intellectual disability, behavioral/psychiatric burden, and — where present — surgical malformations. This is a knowledge gap.

Section 4 — Genetic / Molecular Information

Causal lesion and gene content (Findings F001, F005, F010). The canonical recurrent duplication maps to hg19 chr17:~34.8–36.2 Mb (PMID: 40894066); a representative case spanned chr17:34,460,444–36,243,365 (GRCh37) (PMID: 39793343). Reported CNV sizes range 1.42–1.91 Mb and "included 15 OMIM genes, such as HNF1B, LHX1, and ACACA" (PMID: 39433644).

Gene HGNC / OMIM Role
HNF1B (TCF2) HGNC:11630 / OMIM 189907 Master transcription factor; kidney, pancreas, genitourinary development; leading dosage-sensitive driver
LHX1 HGNC:6593 / OMIM 601999 LIM-homeobox TF; genitourinary and neural development
ACACA HGNC:84 Acetyl-CoA carboxylase alpha; lipid/fatty-acid metabolism
Other interval genes — AATF, DDX52, CCL3P, ZNHIT3, MYO19, PIGW, GGNBP2, DHRS11, MRM1, TADA2A, DUSP14, among others

Variant classification and type. The pathogenic event is a structural variant (recurrent copy-number gain), not a point mutation — classified as pathogenic as a recurrent genomic disorder, though its clinical interpretation is complicated by incomplete penetrance and variable expressivity. Origin is germline. Functional consequence is gene dosage increase (three copies) of the interval genes; for HNF1B this is a gain of dosage (contrast with the reciprocal deletion's haploinsufficiency).

Allele frequency. As a recurrent NDD-CNV, the duplication is present at low frequency in the general/control population — a key reason its penetrance is now estimated lower than early case-control studies suggested (PMID: 34817560; PMID: 22130109).

Modifier genes / epigenetics. No specific modifier genes or epigenetic marks are validated for the duplication. Variable expressivity implies modifiers exist; identifying them is a gap. Co-occurring independent variants (ARX, CCDC103, 16p11.2) act as phenotypic modifiers in reported families.

Chromosomal abnormality. By definition this is a recurrent interstitial microduplication (dup 17q12), NAHR-mediated, flanked by segmental duplications (Finding F001).

Section 5 — Environmental Information

Environmental factors, lifestyle factors, infectious agents: Not applicable. This is a Mendelian genomic disorder with no established toxic, occupational, radiation, dietary, behavioral, or infectious contributors to disease occurrence. The only environmental consideration identified is iatrogenic (drug exposure): valproic acid can precipitate pancreatitis in these patients (see Sections 9/12, Finding F009).

Section 6 — Mechanism / Pathophysiology

Ordered causal chain

  1. NAHR between flanking segmental duplications at 17q12 → results in a recurrent ~1.4–1.5 Mb duplication (three copies of the interval) (Finding F001).
  2. Extra copy of interval genes → leads to increased gene dosage, most consequentially of the dosage-sensitive transcription factor HNF1B (and LHX1, ACACA) (Finding F005).
  3. Elevated HNF1B/LHX1 dosage during development → perturbs transcriptional programs that pattern multiple organ primordia. In zebrafish, overexpression of the HNF1B ortholog vhnf1 "induces expansion of the val expression domain in the hindbrain," demonstrating that increased dosage disrupts CNS (hindbrain) patterning (Finding F011, PMID: 11731484).
  4. Disrupted neurodevelopmental patterning → results in the neurodevelopmental/neuropsychiatric phenotype — intellectual disability, speech/motor delay, autism, epilepsy, ADHD, tics/Tourette, and increased schizophrenia risk (Findings F002, F007; PMID: 27409573, PMID: 24776740, PMID: 40894066).
  5. Branch — organogenesis: dosage perturbation of HNF1B/LHX1 in kidney, pancreas, genitourinary, gut, and (inferred) cardiac primordia → contributes to variable congenital malformations — renal anomalies, duodenal atresia, cardiac defects (tetralogy of Fallot), esophageal atresia, growth anomalies (Findings F004, F008; PMID: 33678321, PMID: 21540130, PMID: 39433644).
  6. Modifier layer (inferred): incomplete penetrance and variable expressivity → modulated by genetic background/second hits and stochastic developmental factors, explaining transmission from mildly/unaffected parents (Finding F003; PMID: 30134084).

Detail by category

  • Molecular pathways / cellular processes. Core mechanism is transcription-factor dosage dysregulation during embryonic regional specification of organ primordia (GO:0009952 anterior/posterior pattern specification; GO:0007389 pattern specification process; GO:0048513 animal organ development). HNF1B is a master regulator of nephrogenesis and pancreatic/hepatic development. In zebrafish, "vhnf1 controls development of multiple organs through regulating regional specification of organ primordia" (PMID: 11731484).
  • Protein dysfunction. No misfolding/aggregation; the defect is quantitative overexpression of otherwise normal proteins (gain of dosage). HNF1B is a POU-homeodomain transcription factor (UniProt P35680).
  • Metabolic changes. ACACA (acetyl-CoA carboxylase) lies in the interval, linking the locus to fatty-acid/lipid metabolism; HNF1B dosage affects pancreatic development. These underlie the syndrome's pancreatic/metabolic susceptibility, clinically relevant to valproate-induced pancreatitis (Finding F009).
  • Immune involvement / tissue damage / oxidative stress: not implicated — this is a developmental patterning disorder, not an inflammatory or degenerative one.
  • Molecular profiling. No disease-specific transcriptomic/proteomic/metabolomic signature for the duplication was identified; mechanistic inference derives from the reciprocal deletion and model organisms. This is a gap.

GO term suggestions: GO:0009952, GO:0007389, GO:0048513, GO:0001822 (kidney development), GO:0031016 (pancreas development), GO:0021537 (telencephalon development). CL term suggestions: CL:0000057 (fibroblast, for iPSC modeling), CL:0002518 (kidney epithelial cell), CL:0000164 (enteroendocrine/pancreatic lineage), CL:0000540 (neuron).

Section 7 — Anatomical Structures Affected

Level Structure UBERON / ontology Involvement
Organ Brain / CNS UBERON:0000955 Primary — neurodevelopment, structural brain anomalies, hindbrain patterning
Organ Kidney UBERON:0002113 Variable — cystic/dysplastic/hypoplastic kidney, VUR
Organ Pancreas UBERON:0001264 Susceptible — pancreatic development; pancreatitis risk
Organ Heart UBERON:0000948 Malformation — tetralogy of Fallot, pulmonary artery anomalies
Organ Duodenum / GI tract UBERON:0002114 Duodenal atresia ("double bubble"), esophageal atresia
Organ Esophagus UBERON:0001043 Esophageal atresia
Body systems Nervous, renal/urinary, cardiovascular, digestive, endocrine — Multi-system

Tissue/cell level. Predominantly neural tissue (neurons, CNS progenitors) and epithelial tissues of kidney, pancreas, and gut. Subcellular: HNF1B/LHX1 act in the nucleus (GO:0005634) as transcription factors. Localization/lateralization: malformations are variably unilateral or bilateral (e.g., unilateral multicystic kidney reported, PMID: 42099279; bilateral hypoplastic kidneys reported, PMID: 21540130); CNS involvement is bilateral/diffuse.

Section 8 — Temporal Development

  • Onset. Spans prenatal/congenital (malformations detectable on ultrasound), infancy/childhood (developmental delay, autism, epilepsy, ADHD, tics), and adolescence/adulthood (schizophrenia). Onset pattern is insidious/chronic for neurodevelopmental features.
  • Progression. Neurodevelopmental features are largely static/stable (non-degenerative). Psychiatric features (schizophrenia, tics) follow their own developmental trajectories. Disease is chronic/lifelong.
  • Course. Not relapsing-remitting at the syndrome level; individual manifestations (epilepsy, tics, psychiatric episodes) may fluctuate.
  • Critical periods. The embryonic/fetal window of organ primordia specification is the mechanistically critical period (during which HNF1B dosage exerts its effect); postnatally, early childhood is the window for developmental/behavioral intervention.
  • Prognosis note. Despite incomplete penetrance, "short-term prognosis appears positive" (PMID: 39286125, Finding F009).

Section 9 — Inheritance and Population

Epidemiology (Finding F003). The reciprocal 17q12 deletion has an estimated population prevalence of ~1:4,000; recurrent NDD-CNVs collectively occur in ~0.48% of newborns (~1 in 200 across 13 loci) (PMID: 32778765). The duplication is rarer and less precisely quantified but is on the order of 1 in several thousand. In prenatal CMA cohorts, 17q12 CNVs are recurrently detected among fetuses with ultrasound anomalies (PMID: 38081620).

Inheritance. - Pattern: Autosomal dominant. - De novo vs inherited: ~one-third de novo, ~two-thirds inherited. "Approximately a third of the newborn recurrent NDD CNVs (34%, N = 20/59) are de novo variants" (PMID: 32778765). The duplication "is often inherited from an apparently unaffected parent" (PMID: 30134084). - Penetrance: Incomplete. "17q12 copy number variants have variable presentations and incomplete penetrance, challenging prenatal counseling and management" (PMID: 39286125). - Expressivity: Highly variable, even within a single family (three-generation family, IQ 52–99; four affected children of a healthy mother, PMID: 30134084; PMID: 36548033). - Anticipation / mosaicism / founder effects / consanguinity: No genetic anticipation expected (not a repeat-expansion disorder). Germline mosaicism not specifically established for the duplication. No founder effect or consanguinity role — recurrence is driven by the NAHR-prone architecture, not by specific population haplotypes.

Population demographics. No strong ethnic predilection; recurrence is architecture-driven and thus pan-ethnic. Sex ratio: roughly balanced, though CNV pathogenicity may be sex-modulated for some neuropsychiatric outcomes (PMID: 34817560). No distinct geographic clustering.

Section 10 — Diagnostics

Cornerstone test — CMA (Finding F006). "17q12 deletions and duplications are two distinct, recurrent chromosomal aberrations usually diagnosed by chromosomal microarray analysis (CMA)" (PMID: 27409573); "Diagnosis is mostly established by chromosomal microarray" (PMID: 38379631).

Modality Utility for 17q12 duplication
Chromosomal microarray (CMA) First-line and definitive; detects the sub-microscopic ~1.4 Mb gain
CNV-seq Equivalent prenatal alternative on amniotic fluid
Karyotyping Insufficient — CNV is below cytogenetic resolution
FISH / MLPA / qPCR Targeted confirmation of the specific CNV
Parental CMA Essential — determines inheritance vs de novo, informs recurrence risk
WES/WGS Not first-line for this CNV; useful when a co-occurring monogenic disorder is suspected (PMID: 40315683, PMID: 40993696)

Prenatal pathway. Detection typically follows fetal ultrasound anomalies — renal (hyperechogenic kidneys), duodenal "double bubble," or cardiac findings — prompting amniocentesis and CMA/CNV-seq (PMID: 33678321; PMID: 39286125; PMID: 38081620).

Biomarkers / laboratory tests. No specific circulating biomarker. Metabolic surveillance (glucose, given HNF1B/pancreatic involvement) and renal function monitoring are advisable. Imaging: renal ultrasound, echocardiography, and brain MRI as clinically indicated.

Differential diagnosis. Reciprocal 17q12 deletion (RCAD/MODY5 — renal cysts + diabetes, more specific phenotype); other recurrent NDD-CNVs (16p11.2, 15q11.2, 22q11.2, 1q21.1); isolated HNF1B point mutations; and co-occurring monogenic disorders that can mimic or compound the phenotype.

Screening. No population newborn screening. Cascade testing of relatives after a proband is diagnosed is appropriate given autosomal-dominant inheritance and frequent transmission from mildly-affected parents.

Section 11 — Outcome / Prognosis

  • Survival / mortality. No excess early mortality is established for the isolated duplication; life-limiting risk derives from severe congenital malformations (major cardiac defects, complex GI atresia) when present. No disease-specific survival curves exist.
  • Morbidity / function. Chief morbidity is neurodevelopmental and psychiatric — intellectual disability, autism, ADHD, epilepsy, tics, and elevated schizophrenia risk — producing variable long-term functional impairment. Congenital malformations contribute surgical morbidity.
  • Disease course. Chronic and lifelong but generally non-progressive; "short-term prognosis appears positive" (PMID: 39286125, Finding F009).
  • Prognostic factors. Severity is unpredictable due to incomplete penetrance/variable expressivity; presence and severity of congenital malformations and degree of intellectual disability are the main determinants. No validated prognostic biomarkers.

Section 12 — Treatment

No curative or disease-specific therapy exists. Management is supportive, symptom-directed, and multidisciplinary (Finding F009): "Treatment involves a multidisciplinary approach" (PMID: 38379631).

Manifestation Intervention NCIT suggestion
Epilepsy Antiseizure medication (avoid valproate where possible) NCIT:C264 (Anticonvulsant)
Developmental delay / ID Early developmental intervention, special education, speech & occupational therapy NCIT:C15318 (Rehabilitation Therapy)
Autism / ADHD / behavioral Behavioral therapy, psychiatric management NCIT:C15328 (Behavioral Therapy)
Psychiatric (schizophrenia) Standard psychiatric pharmacotherapy NCIT:C265 (Antipsychotic Agent)
Renal/metabolic Nephrology surveillance, glucose monitoring NCIT:C15311 (Monitoring)
Duodenal/esophageal atresia Surgical repair NCIT:C15329 (Surgical Procedure)
Cardiac defects (e.g., TOF) Cardiac surgical repair NCIT:C15329

Pharmacovigilance caution (Finding F009). Valproic acid should be used cautiously. A 14-year-old with 17q12 duplication, focal epilepsy, ASD, and ADHD developed valproate-induced acute pancreatitis (lipase 1,572 U/L); "Discontinuation of the VPA led to rapid clinical improvement and normalization of lab values" (probable ADR by Naranjo scale) (PMID: 41700275). This is mechanistically plausible given the syndrome's pancreatic/metabolic susceptibility (HNF1B/ACACA in the interval).

Pharmacogenomics, gene/cell/RNA/targeted/immuno-therapies: Not applicable / none available. No advanced or experimental disease-modifying therapies or registered clinical trials specific to 17q12 duplication were identified. Personalized medicine currently amounts to genotype-informed surveillance (renal, metabolic) and drug selection (valproate avoidance).

Section 13 — Prevention

  • Primary prevention. Not possible — the causal lesion is a germline CNV. The only actionable primary-prevention avenue is reproductive: prenatal diagnosis (CMA/CNV-seq) and preimplantation genetic testing (PGT) for carrier parents.
  • Secondary prevention. Early detection via prenatal ultrasound + CMA, and cascade genetic testing of relatives, enabling early developmental/surveillance intervention.
  • Tertiary prevention. Surveillance and management of complications — renal function monitoring, glucose/metabolic monitoring, timely surgical repair, and avoidance of valproate to prevent iatrogenic pancreatitis.
  • Genetic counseling (central). Given autosomal-dominant inheritance, incomplete penetrance, variable expressivity, and frequent transmission from mildly/unaffected parents, counseling must convey that (a) a carrier parent has a 50% transmission risk, (b) an inheriting child's phenotype is unpredictable, and (c) parental testing is essential (PMID: 30134084; PMID: 39286125).
  • Immunization / public health / environmental interventions: Not applicable.

Section 14 — Other Species / Natural Disease

  • Taxonomy / natural disease. No naturally occurring 17q12-duplication syndrome is described in companion animals or wildlife (OMIA: none identified). The disorder is human-specific in its recurrent-CNV form because it depends on the human-specific segmental-duplication architecture flanking 17q12.
  • Orthologous genes. HNF1B ortholog in mouse (Hnf1b, NCBI Gene 21410) and zebrafish (vhnf1/hnf1ba). LHX1 and ACACA are conserved across vertebrates.
  • Comparative biology / conservation. HNF1B's developmental role is evolutionarily conserved: the zebrafish ortholog regulates gut, pronephros, and hindbrain specification (PMID: 11731484), indicating conserved dosage sensitivity of the mechanism.
  • Zoonotic potential / cross-species transmission: Not applicable (non-infectious genetic disorder).

Section 15 — Model Organisms

Zebrafish (Finding F011). The strongest gain-of-dosage evidence comes from zebrafish vhnf1 (the MODY5/GCKD ortholog). Mutants show "formation of kidney cysts, underdevelopment of the pancreas and the liver, and reduction in size of the otic vesicles," and critically, "overexpression of vhnf1 induces expansion of the val expression domain in the hindbrain" — demonstrating dosage sensitivity in both loss- and gain-of-function directions and directly modeling how increased HNF1B dosage perturbs CNS patterning (PMID: 11731484). This is the most disease-relevant model for the duplication specifically.

Mouse. Hnf1b (MGI; NCBI Gene 21410): complete null is early-embryonic lethal; conditional/heterozygous models produce renal cystic dysplasia and pancreatic hypoplasia — modeling haploinsufficiency (the deletion) more than the duplication. Ciliary-gene knockout mice display an "adipopancreatosis" phenotype linking related pathways to exocrine pancreatic disease (PMID: 42613169).

Model gaps. No published mouse model of the full multigene 17q12 duplication was identified. iPSC/organoid models of patient-derived duplications would be a high-value addition. Model databases: MGI (Hnf1b), ZFIN (vhnf1/hnf1ba), Alliance of Genome Resources.

Model Type Recapitulation Limitation
Zebrafish vhnf1 overexpression gain-of-function Hindbrain patterning perturbation (CNS relevance) Single-gene, not full CNV
Mouse Hnf1b het/conditional KO loss-of-function Renal cystic dysplasia, pancreatic hypoplasia Models the deletion, not duplication
Patient iPSC/organoids in vitro (proposed) Not yet reported for the duplication

Mechanistic Model / Interpretation

   Segmental duplications flanking 17q12
 │  (predispose to NAHR)
 ▼
   Recurrent ~1.4–1.5 Mb DUPLICATION (3 copies)
[HNF1B, LHX1, ACACA + ~12 genes]
 │
 ▼
     ↑ GENE DOSAGE  (HNF1B master TF, dosage-sensitive)
 │
┌────────┴─────────────────────────┐
▼                                   ▼
  Disrupted CNS patterning          Disrupted organogenesis
  (hindbrain, telencephalon)        (kidney, pancreas, gut, heart)
│                                   │
▼                                   ▼
  NEURODEVELOPMENTAL /              VARIABLE CONGENITAL
  NEUROPSYCHIATRIC phenotype        MALFORMATIONS
  • ID, speech/motor delay          • duodenal atresia (double bubble)
  • autism, ADHD                    • tetralogy of Fallot / cardiac
  • epilepsy                        • renal (cystic/hypoplastic)
  • schizophrenia (OR≈4)            • esophageal atresia
  • tics/Tourette (GWS)             • growth anomalies
│                                   │
└──────── MODIFIED BY ──────────────┘
Incomplete penetrance + variable expressivity
(genetic background / second hits / stochastic)
→ transmission from mildly/unaffected parents

The unifying principle is transcription-factor gene-dosage imbalance. The reciprocal deletion (HNF1B haploinsufficiency → RCAD/MODY5, a renal-and-diabetes phenotype) and the duplication (HNF1B overexpression → predominantly neurodevelopmental phenotype) are two ends of one dosage spectrum. The zebrafish gain-of-function data are pivotal because they show that too much HNF1B-ortholog activity, not just too little, disrupts development — grounding the duplication's CNS phenotype in a demonstrated (not merely inferred) mechanism.

Evidence Base

PMID Contribution Supports finding
17924346 First description of reciprocal 17q12 rearrangements; duplication enriched in epilepsy; "first recurrent genomic disorder associated with diabetes" F001
27409573 Danish cohort (38 patients); defines wide dup phenotype; genes HNF1B/LHX1/ACACA; CMA as diagnostic F001, F002, F006
24776740 Swedish schizophrenia CNV study; 17q12 dup OR=4.16, P=0.018 F002
30134084 Multi-generation family; variable penetrance; inheritance from unaffected parent; IQ 52–99 F002, F003
32778765 12,252-trio newborn study; ~34% de novo; prevalence estimates F003
39286125 Prenatal CMA cohort; incomplete penetrance; favorable short-term prognosis F003, F009
33678321 Prenatal duplication features: double bubble, cardiac, growth anomalies F004, F008
21540130 Renal malformations & esophageal atresia can occur with the duplication F004
24487052 HNF1B as dosage-sensitive driver (kidney/pancreas/GU); RCAD F005
38379631 Neuropsychiatric case report; CMA diagnosis; multidisciplinary treatment F006, F009
40894066 / 42749776 Genome-wide significant 17q12 dup association with TS/persistent tic disorder F007
39433644 Prenatal series; cardiovascular anomalies 4/7 incl. TOF; 15 OMIM genes F008, F010
41700275 Valproate-induced pancreatitis in a 17q12 dup patient F009
39793343 Precise GRCh37 coordinates of a 17q12 duplication F010
11731484 Zebrafish vhnf1: dosage sensitivity; overexpression perturbs hindbrain F011

Evidence-type distribution: Predominantly human clinical (case series, prenatal cohorts, psychiatric CNV cohorts, case reports), with supporting model-organism (zebrafish gain-of-function; mouse Hnf1b) mechanistic data. No disease-specific in vitro/omics profiling of the duplication was identified.

Limitations and Knowledge Gaps

  1. Penetrance and expressivity are quantitatively imprecise. Population-based estimates are confounded by higher-than-expected control frequencies; per-phenotype penetrance figures for the duplication remain uncertain.
  2. Frequency data are largely borrowed from the deletion or from pooled recurrent-CNV cohorts; a duplication-specific prevalence is not firmly established.
  3. No duplication-specific molecular profiling (transcriptomics/proteomics/metabolomics) exists; mechanism is inferred from the reciprocal deletion, single genes, and model organisms.
  4. No mouse model of the full multigene duplication; the strongest gain-of-dosage evidence is from a single-gene zebrafish overexpression experiment.
  5. Contributions of non-HNF1B genes (LHX1, ACACA, others) to the duplication phenotype are poorly delineated.
  6. No validated modifiers explain the wide intrafamilial variability; second-hit contributions are documented anecdotally (ARX, CCDC103, 16p11.2) but not systematically.
  7. No quality-of-life, disability, or long-term outcome instruments have been applied to this population.
  8. No disease-modifying therapy or clinical trials — treatment is entirely symptomatic.

Proposed Follow-up Experiments / Actions

  1. Patient-derived iPSC and cerebral/kidney organoid models of the recurrent duplication to obtain duplication-specific transcriptomic/proteomic signatures and test HNF1B-dosage causality directly in human cells.
  2. Engineer a mouse (or zebrafish) model carrying the syntenic multigene duplication to compare against single-gene Hnf1b overexpression and dissect gene-by-gene dosage contributions (LHX1, ACACA).
  3. Assemble a large, prospectively phenotyped 17q12-duplication registry with parental testing to derive robust, per-phenotype penetrance and expressivity estimates and formal QoL/functional outcomes.
  4. Genetic-modifier and second-hit study: WGS across variably affected carriers within families to identify modifier alleles explaining variable expressivity.
  5. Pharmacovigilance analysis (FAERS + registry) to quantify valproate-associated pancreatitis risk in HNF1B-dosage disorders and formalize a valproate-avoidance recommendation.
  6. Systematic cardiac and GI malformation surveillance protocol for prenatally diagnosed cases, given newly recognized tetralogy-of-Fallot and duodenal-atresia associations.
  7. Cross-locus comparison of neuropsychiatric trajectories (schizophrenia, tics, ASD) between 17q12 duplication and other recurrent NDD-CNVs to refine genotype-specific counseling.

Report compiled from 11 confirmed findings and 37 primary papers. Evidence is predominantly human clinical, supported by zebrafish and mouse model-organism data for mechanism. Where information was not available or not applicable (environmental etiology, infectious agents, veterinary natural disease, advanced/experimental therapeutics), this is stated explicitly.

Artifacts

Reference Validation

Checked with linkml-reference-validator 0.2.1.

Outcome Count
References checked 28
Resolved 28
Unresolved (possible confabulation) 0
Unverifiable 0
Quoted claims checked 15
Quoted claims found in source 13
Quoted claims not found in source 2
References weighed for topical relevance 28
On topic 20
Off topic 0

Quotes not found in the cited source

Searched the abstract, any retrieved full text, and the title. A quote drawn from a part of the paper that was not retrieved will appear here too, so check before treating one as invented:

Every one of these was searched against an abstract alone, with no full text retrieved - marked abstract only below. Where full text can be fetched, re-running with it will settle them; where the source publishes only a summary to PubMed, as GeneReviews chapters do, it will not, and the quote has to be checked by hand against the chapter itself.

  • PMID:17924346 (abstract only): "enriched in patients with epilepsy"
  • closest text in source: "We also identified the reciprocal duplication, which appears to be enriched in samples from patients with epilepsy"
  • PMID:39286125 (abstract only): "17q12 copy number variants have variable presentations and incomplete penetrance, challenging prenatal counseling and management"
  • closest text in source: "PURPOSE: 17q12 copy number variants (CNVs) have variable presentations and incomplete penetrance, challenging prenatal counseling and management"

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome Count
Terms checked 45
Resolved 41
Unresolved (possible confabulation) 0
Obsolete 1
Unverifiable 3
Terms whose name was checked 35
Terms named correctly 11
Terms named as a different term 14
Terms whose name is worth a second look 10

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

  • MONDO:0013796 (2 mentions) - the report calls it "MONDO"; MONDO calls it chromosome 17q12 duplication syndrome
  • HP:0001249 (1 mention) - the report calls it "cognitive"; HP calls it Intellectual disability
  • HP:0000717 (1 mention) - the report calls it "behavioral"; HP calls it Autism
  • HP:0100753 (1 mention) - the report calls it "psychiatric"; HP calls it Schizophrenia
  • HP:0001250 (1 mention) - the report calls it "neurological"; HP calls it Seizure
  • HP:0100033 (1 mention) - the report calls it "behavioral"; HP calls it Tics
  • HP:0012443 (1 mention) - the report calls it "CNS malformation"; HP calls it Abnormal brain morphology
  • HP:0001999 (1 mention) - the report calls it "physical"; HP calls it Abnormal facial shape
  • HP:0001388 (1 mention) - the report calls it "connective tissue"; HP calls it obsolete Joint laxity
  • HP:0002247 (1 mention) - the report calls it "GI malformation"; HP calls it Duodenal atresia
  • HP:0002032 (1 mention) - the report calls it "GI malformation"; HP calls it Esophageal atresia
  • NCIT:C15318 (1 mention) - the report calls it "Rehabilitation Therapy"; NCIT calls it Reproducibility
  • NCIT:C15328 (1 mention) - the report calls it "Behavioral Therapy"; NCIT calls it Splenectomy
  • NCIT:C15311 (1 mention) - the report calls it "Monitoring"; NCIT calls it Quality Control

Obsolete terms

These terms are real but deprecated. Citing one is not a fabrication; it does mean the report is naming something the ontology has retired:

  • HP:0001388 (obsolete Joint laxity) (1 mention) - replaced by HP:0001382

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

  • HP:0000750 (1 mention) - the report calls it "neurodevelopmental"; HP calls it Delayed speech and language development, and lists "Poor language development" among its other names
  • HP:0001270 (1 mention) - the report calls it "neurodevelopmental"; HP calls it Motor delay, and lists "Motor developmental delay" among its other names
  • HP:0000077 (1 mention) - the report calls it "renal"; HP calls it Abnormality of the kidney, and lists "Renal anomaly" among its other names
  • HP:0001507 (1 mention) - the report calls it "growth"; HP calls it Growth abnormality, and lists "Growth issue" among its other names
  • CL:0000057 (1 mention) - the report calls it "fibroblast, for iPSC modeling"; CL calls it fibroblast
  • CL:0000164 (1 mention) - the report calls it "enteroendocrine/pancreatic lineage"; CL calls it enteroendocrine cell
  • UBERON:0000955 (1 mention) - the report calls it "Brain / CNS"; UBERON calls it brain
  • UBERON:0002114 (1 mention) - the report calls it "Duodenum / GI tract"; UBERON calls it duodenum
  • NCIT:C265 (1 mention) - the report calls it "Antipsychotic Agent"; NCIT calls it Antidepressant Agent
  • NCIT:C15329 (2 mentions) - the report calls it "Surgical Procedure", "Cardiac surgical repair"; NCIT calls it Surgical Procedure, and lists "Surgical Intervention" among its other names

Terms named inconsistently

The report gives these identifiers more than one name of its own:

  • NCIT:C15329 - called "Surgical Procedure", "Cardiac surgical repair"