Trisomy 13

Genetic MONDO:0018068 Pathograph 7 Show in embeddings browser hereditary disease chromosomal disorder

Trisomy 13 (Patau syndrome) is an autosomal trisomy caused by the presence of an extra chromosome 13 — most often free, homogeneous trisomy, less commonly mosaic trisomy or a Robertsonian translocation. Whole-chromosome gene-dosage imbalance disrupts midline and forebrain development and multiple organ systems, producing the classic clinical triad of cleft lip/palate, microphthalmia/anophthalmia, and postaxial polydactyly, together with holoprosencephaly, congenital heart defects, scalp defects, ear anomalies, and capillary hemangiomas. Expression is highly variable, and the severe birth defects (brain and heart) drive high in-utero and perinatal mortality.

Ask OpenScientist

Ask a research question about Trisomy 13. OpenScientist will conduct autonomous deep research using the Disorder Mechanisms Knowledge Base and PubMed literature (typically 10-30 minutes).

Submitting...

Do not include personal health information in your question. Questions and results are cached in your browser's local storage.

3
Pathophys.
9
Phenotypes
7
Pathograph
1
Genes
1
Medical Actions
2
Subtypes
2
References
◆

Subtypes

2
Free, homogeneous trisomy 13
The most common form (~80%) — three complete copies of chromosome 13 in all cells from meiotic nondisjunction; associated with the full, severe phenotype.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"Most frequent cytogenetic abnormality is free and homogeneous trisomy 13 (80.0%), rarely being detected trisomy mosaics or Robertsonian translocations."
Establishes free homogeneous trisomy 13 as the predominant (~80%) cytogenetic form.
Mosaic trisomy 13 or Robertsonian translocation
Mosaic trisomy (two cell lines) or a Robertsonian translocation. Mosaic cases typically show a less dysmorphic appearance and longer survival than full trisomy 13.
Show evidence (1 reference)
PMID:25943247 SUPPORT Human Clinical
"As a rule, the phenotype is mitigated to a less dysmorphic appearance and longer survival"
Documents the milder phenotype and longer survival of mosaic trisomy 13.
⚙

Pathophysiology

3
Trisomy 13 (Extra Chromosome 13)
Presence of a third copy of chromosome 13 — free homogeneous trisomy (most cases), mosaic trisomy, or a Robertsonian translocation.
Downstream
Chromosome 13 Gene Dosage Imbalance The extra chromosome raises the dosage of all chromosome 13 genes.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"Most frequent cytogenetic abnormality is free and homogeneous trisomy 13 (80.0%), rarely being detected trisomy mosaics or Robertsonian translocations."
Establishes the causal lesion and its cytogenetic forms.
Chromosome 13 Gene Dosage Imbalance
Increased dosage across chromosome 13 genes disrupts midline and forebrain development and multiple organ systems, producing a variably expressive pattern of severe malformations rather than acting through a single critical gene.
Downstream
Impaired Forebrain/Midline Development Disruption of forebrain and midline development, with holoprosencephaly at the severe end.
Congenital Heart Defects
Postaxial Polydactyly
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"Patau syndrome is a disease with variable expression and is characterized by a pattern of abnormal prenatal development characterized by facial dysmorphia, polydactyly and severe birth defects (heart, brain) that generate an increased in utero and perinatal mortality."
Describes the variably expressive multisystem malformation pattern and its mortality.
Impaired Forebrain/Midline Development
Failure of normal forebrain cleavage and midline development produces holoprosencephaly (up to cyclopia at the severe extreme) and midline facial clefting.
forebrain UBERON:0001890 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in forebrain (UBERON:0001890). UBERON:0001890 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Holoprosencephaly
Orofacial Cleft
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
Documents holoprosencephaly among the malformation counts in the cohort.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Trisomy 13 Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

9
Cardiovascular 2
Congenital Heart Defects FREQUENT Abnormal heart morphology HP:0001627 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Congenital heart defect, annotated with Abnormal heart morphology (HP:0001627). HP:0001627 is a phenotype from the Human Phenotype Ontology.
Atrial septal defect was the most common in the cohort.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
Congenital heart anomalies in 10/14 cohort cases (6 with atrial septal defect).
Capillary Hemangioma FREQUENT HP:0001028 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Capillary hemangioma, annotated with Hemangioma (HP:0001028). HP:0001028 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25943247 SUPPORT Human Clinical
"Capillary hemangiomas are a common feature of full trisomy 13, seen in 27-56% of all cases."
Capillary hemangiomas reported in 27-56% of full trisomy 13.
Ear 1
Ear Anomalies FREQUENT Abnormality of the ear HP:0000598 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Abnormal ear morphology, annotated with Abnormality of the ear (HP:0000598). HP:0000598 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
Ear abnormalities in 11/14 cohort cases.
Eye 1
Microphthalmia/Anophthalmia FREQUENT HP:0000568 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Microphthalmia/anophthalmia, annotated with Microphthalmia (HP:0000568). HP:0000568 is a phenotype from the Human Phenotype Ontology.
Microphthalmia or anophthalmia (cyclopia at the severe extreme); a component of the classic diagnostic triad.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"ocular abnormalities (microphthalmia/anophthalmia--7 cases; cyclopia--1 case)"
Microphthalmia/anophthalmia in 7/14 cohort cases; a triad component.
Head and Neck 2
Orofacial Cleft FREQUENT HP:0000202 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Cleft lip and palate, annotated with Orofacial cleft (HP:0000202). HP:0000202 is a phenotype from the Human Phenotype Ontology.
Cleft lip and palate; a component of the classic diagnostic triad.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"the clinical diagnosis being suggested by the triad cleft lip and palate, microphthalmia/anophthalmia and postaxial polydactyly"
Cleft lip and palate is a component of the diagnostic triad.
Broad Nasal Root FREQUENT Wide nasal bridge HP:0000431 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Broad nasal root, annotated with Wide nasal bridge (HP:0000431). HP:0000431 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
Broad nasal root in 10/14 cohort cases.
Integument 1
Scalp Defects (Aplasia Cutis Congenita) FREQUENT HP:0001057 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Scalp defect (aplasia cutis congenita), annotated with Aplasia cutis congenita (HP:0001057). HP:0001057 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
Scalp defects (aplasia cutis) in 6/14 cohort cases.
Limbs 1
Postaxial Polydactyly FREQUENT HP:0100259 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Postaxial polydactyly (HP:0100259). HP:0100259 is a phenotype from the Human Phenotype Ontology.
A component of the classic diagnostic triad.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
Postaxial polydactyly in 7/14 cohort cases; a triad component.
Nervous System 1
Holoprosencephaly OCCASIONAL HP:0001360 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Holoprosencephaly (HP:0001360). HP:0001360 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
Complete holoprosencephaly in 4/14 cohort cases.
🧬

Genetic Associations

1
Trisomy 13 (extra chromosome 13) (Causal)
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"Most frequent cytogenetic abnormality is free and homogeneous trisomy 13 (80.0%), rarely being detected trisomy mosaics or Robertsonian translocations."
Gives the cytogenetic breakdown of the causative trisomy.
💊

Medical Actions

1
Supportive and Palliative Care
Action: supportive careNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is supportive care (NCIT:C15747). NCIT:C15747 is a clinical intervention from the NCI Thesaurus. Ontology label: Supportive Care NCIT:C15747
No curative therapy exists. Management is supportive and individualized — respiratory, feeding, and cardiac support with attention to the severe malformation burden; intensity of care is decided with the family.
🔬

Diagnosis

1
Karyotype Analysis (47,XX,+13 or 47,XY,+13)
Clinical diagnosis suggested by the triad; confirmed cytogenetically (karyotype), often prenatally.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"the clinical diagnosis being suggested by the triad cleft lip and palate, microphthalmia/anophthalmia and postaxial polydactyly"
The clinical triad prompts cytogenetic confirmation of trisomy 13.
📊

Prevalence

1
Live births
Birth Prevalence 6.7 per 100,000 (5.0–10.0) 1–9 per 100,000 (births)
Incidence ~1 in 10,000 to 1 in 20,000 (5-10 per 100,000). Live-born prevalence is reduced by high in-utero and perinatal mortality.
Show evidence (1 reference)
PMID:24340511 SUPPORT Human Clinical
"Patau syndrome has an incidence of 1/10.000-20.000, the clinical diagnosis being suggested by the triad cleft lip and palate, microphthalmia/anophthalmia and postaxial polydactyly."
Provides the incidence range and the diagnostic clinical triad.
{ }

Source YAML

click to show 
name: Trisomy 13
creation_date: "2026-08-22T00:00:00Z"
description: >-
  Trisomy 13 (Patau syndrome) is an autosomal trisomy caused by the presence of an
  extra chromosome 13 — most often free, homogeneous trisomy, less commonly mosaic
  trisomy or a Robertsonian translocation. Whole-chromosome gene-dosage imbalance
  disrupts midline and forebrain development and multiple organ systems, producing
  the classic clinical triad of cleft lip/palate, microphthalmia/anophthalmia, and
  postaxial polydactyly, together with holoprosencephaly, congenital heart defects,
  scalp defects, ear anomalies, and capillary hemangiomas. Expression is highly
  variable, and the severe birth defects (brain and heart) drive high in-utero and
  perinatal mortality.
category: Genetic
synonyms:
- Patau syndrome
- trisomy 13 syndrome
- complete trisomy 13
parents:
- hereditary disease
- chromosomal disorder
disease_term:
  preferred_term: trisomy 13
  term:
    id: MONDO:0018068
    label: trisomy 13
has_subtypes:
- name: Full trisomy 13
  display_name: Free, homogeneous trisomy 13
  description: >-
    The most common form (~80%) — three complete copies of chromosome 13 in all
    cells from meiotic nondisjunction; associated with the full, severe phenotype.
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Most frequent cytogenetic abnormality is free and homogeneous trisomy 13 (80.0%), rarely being detected trisomy mosaics or Robertsonian translocations."
    explanation: Establishes free homogeneous trisomy 13 as the predominant (~80%) cytogenetic form.
- name: Mosaic or translocation trisomy 13
  display_name: Mosaic trisomy 13 or Robertsonian translocation
  description: >-
    Mosaic trisomy (two cell lines) or a Robertsonian translocation. Mosaic cases
    typically show a less dysmorphic appearance and longer survival than full
    trisomy 13.
  evidence:
  - reference: PMID:25943247
    reference_title: "Cutaneous manifestations in trisomy 13 mosaicism: A rare case and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "As a rule, the phenotype is mitigated to a less dysmorphic appearance and longer survival"
    explanation: Documents the milder phenotype and longer survival of mosaic trisomy 13.
prevalence:
- population: Live births
  measure_type: BIRTH_PREVALENCE
  prevalence_class: BAND_1_9_PER_100000
  rate_per_100000: 6.7
  rate_low: 5.0
  rate_high: 10.0
  notes: >-
    Incidence ~1 in 10,000 to 1 in 20,000 (5-10 per 100,000). Live-born prevalence
    is reduced by high in-utero and perinatal mortality.
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patau syndrome has an incidence of 1/10.000-20.000, the clinical diagnosis being suggested by the triad cleft lip and palate, microphthalmia/anophthalmia and postaxial polydactyly."
    explanation: Provides the incidence range and the diagnostic clinical triad.
pathophysiology:
- name: Trisomy 13 (Extra Chromosome 13)
  biological_scale: MOLECULAR
  description: >-
    Presence of a third copy of chromosome 13 — free homogeneous trisomy (most
    cases), mosaic trisomy, or a Robertsonian translocation.
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Most frequent cytogenetic abnormality is free and homogeneous trisomy 13 (80.0%), rarely being detected trisomy mosaics or Robertsonian translocations."
    explanation: Establishes the causal lesion and its cytogenetic forms.
  downstream:
  - target: Chromosome 13 Gene Dosage Imbalance
    causal_link_type: DIRECT
    description: The extra chromosome raises the dosage of all chromosome 13 genes.
- name: Chromosome 13 Gene Dosage Imbalance
  biological_scale: MOLECULAR
  description: >-
    Increased dosage across chromosome 13 genes disrupts midline and forebrain
    development and multiple organ systems, producing a variably expressive pattern
    of severe malformations rather than acting through a single critical gene.
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patau syndrome is a disease with variable expression and is characterized by a pattern of abnormal prenatal development characterized by facial dysmorphia, polydactyly and severe birth defects (heart, brain) that generate an increased in utero and perinatal mortality."
    explanation: Describes the variably expressive multisystem malformation pattern and its mortality.
  downstream:
  - target: Impaired Forebrain/Midline Development
    causal_link_type: DIRECT
    description: Disruption of forebrain and midline development, with holoprosencephaly at the severe end.
  - target: Congenital Heart Defects
    causal_link_type: DIRECT
  - target: Postaxial Polydactyly
    causal_link_type: DIRECT
- name: Impaired Forebrain/Midline Development
  biological_scale: TISSUE
  description: >-
    Failure of normal forebrain cleavage and midline development produces
    holoprosencephaly (up to cyclopia at the severe extreme) and midline facial
    clefting.
  locations:
  - preferred_term: forebrain
    term:
      id: UBERON:0001890
      label: forebrain
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
    explanation: Documents holoprosencephaly among the malformation counts in the cohort.
  downstream:
  - target: Holoprosencephaly
    causal_link_type: DIRECT
  - target: Orofacial Cleft
    causal_link_type: DIRECT
phenotypes:
- category: Craniofacial
  name: Orofacial Cleft
  frequency: FREQUENT
  diagnostic: true
  notes: Cleft lip and palate; a component of the classic diagnostic triad.
  phenotype_term:
    preferred_term: Cleft lip and palate
    term:
      id: HP:0000202
      label: Orofacial cleft
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "the clinical diagnosis being suggested by the triad cleft lip and palate, microphthalmia/anophthalmia and postaxial polydactyly"
    explanation: Cleft lip and palate is a component of the diagnostic triad.
- category: Ocular
  name: Microphthalmia/Anophthalmia
  frequency: FREQUENT
  notes: Microphthalmia or anophthalmia (cyclopia at the severe extreme); a component of the classic diagnostic triad.
  phenotype_term:
    preferred_term: Microphthalmia/anophthalmia
    term:
      id: HP:0000568
      label: Microphthalmia
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ocular abnormalities (microphthalmia/anophthalmia--7 cases; cyclopia--1 case)"
    explanation: Microphthalmia/anophthalmia in 7/14 cohort cases; a triad component.
- category: Limbs
  name: Postaxial Polydactyly
  frequency: FREQUENT
  diagnostic: true
  notes: A component of the classic diagnostic triad.
  phenotype_term:
    preferred_term: Postaxial polydactyly
    term:
      id: HP:0100259
      label: Postaxial polydactyly
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
    explanation: Postaxial polydactyly in 7/14 cohort cases; a triad component.
- category: Neurologic
  name: Holoprosencephaly
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Holoprosencephaly
    term:
      id: HP:0001360
      label: Holoprosencephaly
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
    explanation: Complete holoprosencephaly in 4/14 cohort cases.
- category: Cardiac
  name: Congenital Heart Defects
  frequency: FREQUENT
  notes: Atrial septal defect was the most common in the cohort.
  phenotype_term:
    preferred_term: Congenital heart defect
    term:
      id: HP:0001627
      label: Abnormal heart morphology
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
    explanation: Congenital heart anomalies in 10/14 cohort cases (6 with atrial septal defect).
- category: Skin
  name: Scalp Defects (Aplasia Cutis Congenita)
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Scalp defect (aplasia cutis congenita)
    term:
      id: HP:0001057
      label: Aplasia cutis congenita
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
    explanation: Scalp defects (aplasia cutis) in 6/14 cohort cases.
- category: Craniofacial
  name: Ear Anomalies
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Abnormal ear morphology
    term:
      id: HP:0000598
      label: Abnormality of the ear
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
    explanation: Ear abnormalities in 11/14 cohort cases.
- category: Craniofacial
  name: Broad Nasal Root
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Broad nasal root
    term:
      id: HP:0000431
      label: Wide nasal bridge
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases)"
    explanation: Broad nasal root in 10/14 cohort cases.
- category: Skin
  name: Capillary Hemangioma
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Capillary hemangioma
    term:
      id: HP:0001028
      label: Hemangioma
  evidence:
  - reference: PMID:25943247
    reference_title: "Cutaneous manifestations in trisomy 13 mosaicism: A rare case and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Capillary hemangiomas are a common feature of full trisomy 13, seen in 27-56% of all cases."
    explanation: Capillary hemangiomas reported in 27-56% of full trisomy 13.
genetic:
- name: Trisomy 13 (extra chromosome 13)
  association: Causal
  notes: >-
    Presence of an extra copy of chromosome 13 — free homogeneous trisomy (~80%,
    typically meiotic nondisjunction), mosaic trisomy, or a Robertsonian
    translocation (copy-number gain). No coordinate slot exists in the schema; the
    whole-chromosome gain is recorded here in prose.
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Most frequent cytogenetic abnormality is free and homogeneous trisomy 13 (80.0%), rarely being detected trisomy mosaics or Robertsonian translocations."
    explanation: Gives the cytogenetic breakdown of the causative trisomy.
diagnosis:
- name: Karyotype Analysis
  presence: 47,XX,+13 or 47,XY,+13
  notes: Clinical diagnosis suggested by the triad; confirmed cytogenetically (karyotype), often prenatally.
  evidence:
  - reference: PMID:24340511
    reference_title: "Phenotypic variability in Patau syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "the clinical diagnosis being suggested by the triad cleft lip and palate, microphthalmia/anophthalmia and postaxial polydactyly"
    explanation: The clinical triad prompts cytogenetic confirmation of trisomy 13.
treatments:
- name: Supportive and Palliative Care
  description: >-
    No curative therapy exists. Management is supportive and individualized —
    respiratory, feeding, and cardiac support with attention to the severe
    malformation burden; intensity of care is decided with the family.
  treatment_term:
    preferred_term: supportive care
    term:
      id: NCIT:C15747
      label: Supportive Care
references:
- reference: PMID:24340511
  title: "Phenotypic variability in Patau syndrome."
- reference: PMID:25943247
  title: "Cutaneous manifestations in trisomy 13 mosaicism: A rare case and review of the literature."
📚

References & Deep Research

References

2
PMID:24340511
Phenotypic variability in Patau syndrome.
No top-level findings curated for this source.
PMID:25943247
Cutaneous manifestations in trisomy 13 mosaicism: A rare case and review of the literature.
No top-level findings curated for this source.