Inherited Ichthyosis

Mendelian MONDO:0015947 Pathograph 16 ichthyosis hereditary skin disorder

Inherited ichthyosis is a heterogeneous group of Mendelian disorders of cornification affecting most or all of the integument. The shared clinical surface is abnormal epidermal scaling and/or hyperkeratosis, but the underlying causes span defects in keratinocyte differentiation, cornified envelope formation, epidermal lipid handling, protease control, and skin barrier maintenance.

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3
Inheritance
5
Pathophys.
9
Phenotypes
16
Pathograph
5
Genes
4
Treatments
5
Subtypes
3
Trials
7
References
1
Deep Research
👪

Inheritance

3
Autosomal dominant inheritance HP:0000006
Some inherited ichthyosis subtypes, including ichthyosis vulgaris and many keratinopathic ichthyoses, follow autosomal dominant inheritance.
Autosomal dominant inheritance
Autosomal recessive inheritance HP:0000007
Several severe inherited ichthyosis groups, including autosomal recessive congenital ichthyosis and Netherton syndrome, are autosomal recessive.
Autosomal recessive inheritance
X-linked recessive inheritance HP:0001419
X-linked ichthyosis is the major X-linked inherited ichthyosis subtype.
X-linked recessive inheritance
◆

Subtypes

5
Ichthyosis Vulgaris MONDO:0024304
Common inherited ichthyosis characterized by generalized scaling and desquamation.
X-Linked Ichthyosis MONDO:0010622
X-linked recessive inherited ichthyosis, classically associated with steroid sulfatase deficiency.
Autosomal Recessive Congenital Ichthyosis MONDO:0017265
Nonsyndromic autosomal recessive congenital ichthyosis spectrum, including lamellar ichthyosis, congenital ichthyosiform erythroderma, and harlequin ichthyosis.
Keratinopathic Ichthyosis MONDO:0017266
Inherited ichthyosis group caused by pathogenic variants in keratin genes, with epidermolytic ichthyosis as a well-characterized subtype.
Netherton Syndrome MONDO:0009735
Syndromic inherited ichthyosis caused by SPINK5 loss of function, with skin-barrier failure, hair-shaft abnormality, and atopic manifestations.
⚙

Pathophysiology

5
Disrupted Keratinocyte Differentiation and Cornification
Inherited ichthyosis subtypes converge on abnormal keratinocyte terminal differentiation and cornification, producing defective formation and turnover of the stratum corneum.
keratinocyte link
keratinocyte differentiation link ⚠ ABNORMAL keratinization link ⚠ ABNORMAL
skin epidermis link
Downstream
Stratum Corneum Barrier Impairment
Show evidence (1 reference)
DOI:10.3390/biomedicines12051112 SUPPORT Human Clinical
"Inherited ichthyoses are a group of clinically and genetically heterogeneous rare disorders of skin keratinization with overlapping phenotypes."
Supports the shared keratinization/cornification phenotype across the inherited ichthyosis group.
Epidermal Lipid Metabolism Defect
Several autosomal recessive congenital ichthyosis genes perturb epidermal lipid processing, lipid transport, or cornified-envelope assembly, impairing lamellar barrier formation in differentiating keratinocytes.
keratinocyte link
TGM1 link ABCA12 link ALOX12B link ALOXE3 link CYP4F22 link NIPAL4 link
lipid transport link ⚠ ABNORMAL ceramide biosynthetic process link ⚠ ABNORMAL establishment of skin barrier link ⚠ ABNORMAL
skin epidermis link
Downstream
Stratum Corneum Barrier Impairment
Show evidence (1 reference)
PMID:38588653 SUPPORT Human Clinical
"Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in 18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%), ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1, and SDR9C7 in 1 patient each (1.4%)."
Supports the major ARCI genes that converge on epidermal lipid and cornified-envelope barrier biology.
Stratum Corneum Barrier Impairment
Abnormal cornification compromises stratum corneum structure and barrier performance, increasing scale retention, skin dryness, and vulnerability to dehydration or inflammation in severe forms.
keratinocyte link
keratinization link ⚠ ABNORMAL
stratum corneum of epidermis link
Downstream
Ichthyosis
Hyperkeratosis
Skin Microbiome Dysbiosis
Show evidence (1 reference)
DOI:10.1186/s40246-024-00603-x SUPPORT Human Clinical
"Patients present with epidermal scaling, fissuring, chronic inflammation, and increased susceptibility to infections."
Supports barrier impairment as a clinical state linking scaling, fissuring, inflammation, and infection susceptibility.
Skin Microbiome Dysbiosis
Defective congenital ichthyosis skin barriers are associated with altered epidermal microbial communities, reduced commensal microbiota, and higher pathogenic colonization.
skin epidermis link
Downstream
Th17/JAK-STAT Inflammatory Activation
Recurrent Skin Infections
Show evidence (1 reference)
DOI:10.1186/s40246-024-00603-x SUPPORT Human Clinical
"Microbiome meta-analysis showed distinct microbial populations, decreases in commensal microbiota, and higher colonization by pathogenic species associated with CI; these were correlated with increased production of inflammatory cytokines and Th17- and JAK/STAT-signaling pathways in peripheral..."
Directly supports microbiome dysbiosis as a congenital ichthyosis mechanism linked to inflammation and pathogenic colonization.
Th17/JAK-STAT Inflammatory Activation
Barrier and microbiome abnormalities in congenital ichthyosis are associated with increased inflammatory cytokines and Th17/JAK-STAT pathway activation.
T-helper 17 cell link
inflammatory response link ↑ INCREASED T-helper 17 type immune response link ↑ INCREASED JAK-STAT signaling pathway link ↑ INCREASED
Downstream
Erythroderma
Recurrent Skin Infections
Show evidence (1 reference)
DOI:10.1186/s40246-024-00603-x SUPPORT Human Clinical
"Microbiome meta-analysis showed distinct microbial populations, decreases in commensal microbiota, and higher colonization by pathogenic species associated with CI; these were correlated with increased production of inflammatory cytokines and Th17- and JAK/STAT-signaling pathways in peripheral..."
Supports inflammatory cytokine, Th17, and JAK-STAT activation downstream of congenital ichthyosis barrier and microbiome abnormalities.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Inherited Ichthyosis 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
Immune 2
Erythroderma Erythroderma (HP:0001019)
Show evidence (1 reference)
PMID:38588653 SUPPORT Human Clinical
"Seventy-four consecutive patients (mean age 11.0 years, range 0.1-48.8) affected with lamellar ichthyosis (50/74, 67.5%), congenital ichthyosiform erythroderma (18/74, 24.3%), harlequin ichthyosis (two/74, 2.7%), and other minor ARCI subtypes (four/74, 5.4%) were enrolled."
Directly supports erythroderma as part of the ARCI clinical spectrum.
Recurrent Skin Infections Recurrent infections (HP:0002719)
Show evidence (1 reference)
DOI:10.1186/s40246-024-00603-x SUPPORT Human Clinical
"Patients present with epidermal scaling, fissuring, chronic inflammation, and increased susceptibility to infections."
Directly supports increased susceptibility to infections in congenital ichthyosis.
Integument 6
Ichthyosis Ichthyosis (HP:0008064)
Show evidence (1 reference)
DOI:10.1186/s40246-024-00603-x SUPPORT Human Clinical
"Patients present with epidermal scaling, fissuring, chronic inflammation, and increased susceptibility to infections."
Supports scaling as a central congenital ichthyosis phenotype.
Hyperkeratosis Hyperkeratosis (HP:0000962)
Show evidence (1 reference)
clinicaltrials:NCT03041038 SUPPORT Human Clinical
"The ichthyoses are a group of lifelong genetic disorders which share characteristics of generalized skin thickening, scaling and underlying cutaneous inflammation."
Supports skin thickening and scaling as core inherited ichthyosis phenotypes.
Palmoplantar keratoderma Palmoplantar keratoderma (HP:0000982)
Show evidence (1 reference)
PMID:38588653 SUPPORT Human Clinical
"Among specific phenotypic features, psoriasis-like lesions as well as a trunk reticulate scale pattern and striated keratoderma were present in NIPAL4-mutated patients."
Supports palmoplantar/striated keratoderma as a subtype-associated inherited ichthyosis feature.
Pruritus Pruritus (HP:0000989)
Hypohidrosis Hypohidrosis (HP:0000966)
Alopecia Alopecia (HP:0001596)
Show evidence (1 reference)
PMID:38588653 SUPPORT Human Clinical
"Alopecia, ectropion, and eclabium were significantly associated with TGM1 and ABCA12 mutations, and large, thick, and brownish scales with TGM1 mutations."
Supports alopecia as a genotype-associated ARCI phenotype.
Metabolism 1
Heat Intolerance Heat intolerance (HP:0002046)
🧬

Genetic Associations

5
FLG (Causative biallelic loss-of-function variants in ichthyosis vulgaris)
Autosomal semidominant inheritance
Show evidence (1 reference)
DOI:10.3390/biomedicines12051112 SUPPORT Human Clinical
"Three patients had biallelic loss-of-function variants in FLG, whereas 6/11 males were affected by X-linked ichthyosis."
Supports FLG loss of function as the molecular basis for an inherited ichthyosis subtype in this cohort.
STS (Causative steroid sulfatase deficiency in X-linked ichthyosis)
X-linked recessive
Show evidence (1 reference)
DOI:10.3390/biomedicines12051112 PARTIAL Human Clinical
"Three patients had biallelic loss-of-function variants in FLG, whereas 6/11 males were affected by X-linked ichthyosis."
Supports X-linked ichthyosis representation in the cohort; STS is the canonical steroid-sulfatase gene for this subtype.
TGM1 (Causative biallelic pathogenic variants in autosomal recessive congenital ichthyosis)
Autosomal recessive
Show evidence (1 reference)
PMID:38588653 SUPPORT Human Clinical
"Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in 18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%), ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1, and SDR9C7 in 1 patient each (1.4%)."
Supports TGM1 as a common causative ARCI gene.
ALOX12B (Causative biallelic pathogenic variants in autosomal recessive congenital ichthyosis)
Autosomal recessive
Show evidence (1 reference)
PMID:38588653 SUPPORT Human Clinical
"Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in 18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%), ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1, and SDR9C7 in 1 patient each (1.4%)."
Supports ALOX12B as a common causative ARCI gene.
ABCA12 (Causative biallelic pathogenic variants in autosomal recessive congenital ichthyosis, including harlequin ichthyosis)
Autosomal recessive
Show evidence (1 reference)
PMID:38588653 SUPPORT Human Clinical
"Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in 18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%), ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1, and SDR9C7 in 1 patient each (1.4%)."
Supports ABCA12 as a recurrent causative ARCI gene in the cohort.
💊

Treatments

4
Topical emollients and keratolytic/supportive therapy
Action: supportive care MAXO:0000950
Barrier-directed topical care with emollients and keratolytics is standard symptomatic management for scaling, fissuring, and dryness across inherited ichthyosis subtypes.
Target Phenotypes: Ichthyosis ↗
Retinoid pharmacotherapy
Action: Pharmacotherapy NCIT:C15986
Agent: isotretinoin ↗
Systemic or topical retinoid therapy can reduce severe scaling and hyperkeratosis, including topical isotretinoin TMB-001 studied in the CONTROL trial.
Target Phenotypes: Ichthyosis ↗
Show evidence (1 reference)
clinicaltrials:NCT04154293 SUPPORT Human Clinical
"The purpose of this study is to investigate the efficacy and safety of two concentrations of topically applied ointment formulation of isotretinoin called TMB-001 (0.05% and 0.1% isotretinoin) in subjects 9 years of age and older for the treatment of congenital ichthyosis (CI), including..."
Supports topical isotretinoin TMB-001 as a congenital ichthyosis therapy evaluated in a randomized clinical study.
Topical TGM1 gene therapy
Action: gene therapy MAXO:0001001
KB105 is a topical HSV-1 vector expressing TGM1 under clinical investigation for TGM1-deficient autosomal recessive congenital ichthyosis.
Mechanism Target:
RESTORES Epidermal Lipid Metabolism Defect — Topical TGM1 expression is intended to restore deficient transglutaminase 1 activity in affected skin.
Show evidence (1 reference)
clinicaltrials:NCT04047732 SUPPORT Human Clinical
"This study is an intra-patient comparison of KB105 and placebo-administered Target Areas. The primary objectives of this study are to evaluate safety and Investigator Global Assessment (IGA) scale improvement of topically administered KB105."
Supports clinical testing of topical KB105 for TGM1-deficient ARCI.
IL-17A-targeting biologic therapy
Action: Pharmacotherapy NCIT:C15986
Agent: Secukinumab ↗
Secukinumab has been studied as a mechanism-based immunomodulatory approach for ichthyoses with cutaneous inflammation and IL-17 pathway activation.
Mechanism Target:
INHIBITS Th17/JAK-STAT Inflammatory Activation — IL-17A blockade is intended to reduce inflammatory signaling in selected ichthyosis patients with immune activation.
Show evidence (1 reference)
clinicaltrials:NCT03041038 PARTIAL Human Clinical
"The ichthyoses are a group of lifelong genetic disorders which share characteristics of generalized skin thickening, scaling and underlying cutaneous inflammation."
Supports inflammatory pathway targeting in ichthyoses, while the trial is not specific to all inherited ichthyosis subtypes.
🔬

Clinical Trials

3
NCT04047732 PHASE_I
Phase I/II topical KB105 intra-patient comparison trial for TGM1-deficient ARCI.
Show evidence (1 reference)
clinicaltrials:NCT04047732 SUPPORT Human Clinical
"This study is an intra-patient comparison of KB105 and placebo-administered Target Areas. The primary objectives of this study are to evaluate safety and Investigator Global Assessment (IGA) scale improvement of topically administered KB105."
Supports this trial as topical KB105 clinical testing in TGM1-deficient ARCI.
NCT05735158 PHASE_II
Randomized placebo-controlled topical KB105 study in children and adults with ARCI.
Show evidence (1 reference)
clinicaltrials:NCT05735158 SUPPORT Human Clinical
"KB105-02 is an intrasubject randomized, placebo-controlled, double-blind study to evaluate the safety and efficacy of KB105 in children and adults with autosomal recessive congenital ichthyosis (ARCI)."
Supports this as a randomized phase 2 ARCI KB105 trial record.
NCT03041038 PHASE_II
Phase 2 secukinumab trial in ichthyoses testing IL-17A-targeted immunomodulation for inflammatory skin thickening and scaling.
Show evidence (1 reference)
clinicaltrials:NCT03041038 PARTIAL Human Clinical
"The ichthyoses are a group of lifelong genetic disorders which share characteristics of generalized skin thickening, scaling and underlying cutaneous inflammation."
Supports this trial as relevant to inflammatory ichthyosis biology, although not specific to every inherited ichthyosis subtype.
{ }

Source YAML

click to show 
name: Inherited Ichthyosis
creation_date: "2026-05-07T15:56:15Z"
updated_date: "2026-05-07T16:31:48Z"
category: Mendelian
description: >-
  Inherited ichthyosis is a heterogeneous group of Mendelian disorders of
  cornification affecting most or all of the integument. The shared clinical
  surface is abnormal epidermal scaling and/or hyperkeratosis, but the
  underlying causes span defects in keratinocyte differentiation, cornified
  envelope formation, epidermal lipid handling, protease control, and skin
  barrier maintenance.
synonyms:
- genetic ichthyosis
- hereditary ichthyosis
- congenital ichthyosis
disease_term:
  preferred_term: inherited ichthyosis
  term:
    id: MONDO:0015947
    label: inherited ichthyosis
parents:
- ichthyosis
- hereditary skin disorder
has_subtypes:
- name: Ichthyosis Vulgaris
  display_name: Ichthyosis Vulgaris
  subtype_term:
    preferred_term: ichthyosis vulgaris
    term:
      id: MONDO:0024304
      label: ichthyosis vulgaris
  description: >-
    Common inherited ichthyosis characterized by generalized scaling and
    desquamation.
- name: X-Linked Ichthyosis
  display_name: X-Linked Ichthyosis
  subtype_term:
    preferred_term: X-linked ichthyosis
    term:
      id: MONDO:0010622
      label: recessive X-linked ichthyosis
  description: >-
    X-linked recessive inherited ichthyosis, classically associated with
    steroid sulfatase deficiency.
- name: Autosomal Recessive Congenital Ichthyosis
  display_name: Autosomal Recessive Congenital Ichthyosis
  subtype_term:
    preferred_term: autosomal recessive congenital ichthyosis
    term:
      id: MONDO:0017265
      label: autosomal recessive congenital ichthyosis
  description: >-
    Nonsyndromic autosomal recessive congenital ichthyosis spectrum, including
    lamellar ichthyosis, congenital ichthyosiform erythroderma, and harlequin
    ichthyosis.
- name: Keratinopathic Ichthyosis
  display_name: Keratinopathic Ichthyosis
  subtype_term:
    preferred_term: keratinopathic ichthyosis
    term:
      id: MONDO:0017266
      label: keratinopathic ichthyosis
  description: >-
    Inherited ichthyosis group caused by pathogenic variants in keratin genes,
    with epidermolytic ichthyosis as a well-characterized subtype.
- name: Netherton Syndrome
  display_name: Netherton Syndrome
  subtype_term:
    preferred_term: Netherton syndrome
    term:
      id: MONDO:0009735
      label: Netherton syndrome
  description: >-
    Syndromic inherited ichthyosis caused by SPINK5 loss of function, with
    skin-barrier failure, hair-shaft abnormality, and atopic manifestations.
inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    Some inherited ichthyosis subtypes, including ichthyosis vulgaris and many
    keratinopathic ichthyoses, follow autosomal dominant inheritance.
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    Several severe inherited ichthyosis groups, including autosomal recessive
    congenital ichthyosis and Netherton syndrome, are autosomal recessive.
- name: X-linked recessive inheritance
  inheritance_term:
    preferred_term: X-linked recessive inheritance
    term:
      id: HP:0001419
      label: X-linked recessive inheritance
  description: >-
    X-linked ichthyosis is the major X-linked inherited ichthyosis subtype.
pathophysiology:
- name: Disrupted Keratinocyte Differentiation and Cornification
  description: >-
    Inherited ichthyosis subtypes converge on abnormal keratinocyte terminal
    differentiation and cornification, producing defective formation and
    turnover of the stratum corneum.
  cell_types:
  - preferred_term: keratinocyte
    term:
      id: CL:0000312
      label: keratinocyte
  biological_processes:
  - preferred_term: keratinocyte differentiation
    term:
      id: GO:0030216
      label: keratinocyte differentiation
    modifier: ABNORMAL
  - preferred_term: keratinization
    term:
      id: GO:0031424
      label: keratinization
    modifier: ABNORMAL
  locations:
  - preferred_term: skin epidermis
    term:
      id: UBERON:0001003
      label: skin epidermis
  downstream:
  - target: Stratum Corneum Barrier Impairment
    causal_link_type: DIRECT
  evidence:
  - reference: DOI:10.3390/biomedicines12051112
    reference_title: Comprehensive Molecular Analysis of Disease-Related Genes
      as First-Tier Test for Early Diagnosis, Classification, and Management
      of Patients Affected by Nonsyndromic Ichthyosis
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Inherited ichthyoses are a group of clinically and genetically
      heterogeneous rare disorders of skin keratinization with overlapping
      phenotypes.
    explanation: >-
      Supports the shared keratinization/cornification phenotype across the
      inherited ichthyosis group.
- name: Epidermal Lipid Metabolism Defect
  description: >-
    Several autosomal recessive congenital ichthyosis genes perturb epidermal
    lipid processing, lipid transport, or cornified-envelope assembly, impairing
    lamellar barrier formation in differentiating keratinocytes.
  cell_types:
  - preferred_term: keratinocyte
    term:
      id: CL:0000312
      label: keratinocyte
  biological_processes:
  - preferred_term: lipid transport
    term:
      id: GO:0006869
      label: lipid transport
    modifier: ABNORMAL
  - preferred_term: ceramide biosynthetic process
    term:
      id: GO:0046513
      label: ceramide biosynthetic process
    modifier: ABNORMAL
  - preferred_term: establishment of skin barrier
    term:
      id: GO:0061436
      label: establishment of skin barrier
    modifier: ABNORMAL
  genes:
  - preferred_term: TGM1
    term:
      id: hgnc:11777
      label: TGM1
  - preferred_term: ABCA12
    term:
      id: hgnc:14637
      label: ABCA12
  - preferred_term: ALOX12B
    term:
      id: hgnc:430
      label: ALOX12B
  - preferred_term: ALOXE3
    term:
      id: hgnc:13743
      label: ALOXE3
  - preferred_term: CYP4F22
    term:
      id: hgnc:26820
      label: CYP4F22
  - preferred_term: NIPAL4
    term:
      id: hgnc:28018
      label: NIPAL4
  locations:
  - preferred_term: skin epidermis
    term:
      id: UBERON:0001003
      label: skin epidermis
  downstream:
  - target: Stratum Corneum Barrier Impairment
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:38588653
    reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
      Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
      Features in 74 Italian Patients'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in
      18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%),
      ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1,
      and SDR9C7 in 1 patient each (1.4%).
    explanation: >-
      Supports the major ARCI genes that converge on epidermal lipid and
      cornified-envelope barrier biology.
- name: Stratum Corneum Barrier Impairment
  description: >-
    Abnormal cornification compromises stratum corneum structure and barrier
    performance, increasing scale retention, skin dryness, and vulnerability to
    dehydration or inflammation in severe forms.
  cell_types:
  - preferred_term: keratinocyte
    term:
      id: CL:0000312
      label: keratinocyte
  biological_processes:
  - preferred_term: keratinization
    term:
      id: GO:0031424
      label: keratinization
    modifier: ABNORMAL
  locations:
  - preferred_term: stratum corneum of epidermis
    term:
      id: UBERON:0002027
      label: stratum corneum of epidermis
  downstream:
  - target: Ichthyosis
    causal_link_type: DIRECT
  - target: Hyperkeratosis
    causal_link_type: DIRECT
  - target: Skin Microbiome Dysbiosis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: DOI:10.1186/s40246-024-00603-x
    reference_title: Altered skin microbiome, inflammation, and JAK/STAT
      signaling in Southeast Asian ichthyosis patients
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients present with epidermal scaling, fissuring, chronic inflammation,
      and increased susceptibility to infections.
    explanation: >-
      Supports barrier impairment as a clinical state linking scaling,
      fissuring, inflammation, and infection susceptibility.
- name: Skin Microbiome Dysbiosis
  description: >-
    Defective congenital ichthyosis skin barriers are associated with altered
    epidermal microbial communities, reduced commensal microbiota, and higher
    pathogenic colonization.
  locations:
  - preferred_term: skin epidermis
    term:
      id: UBERON:0001003
      label: skin epidermis
  downstream:
  - target: Th17/JAK-STAT Inflammatory Activation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Recurrent Skin Infections
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: DOI:10.1186/s40246-024-00603-x
    reference_title: Altered skin microbiome, inflammation, and JAK/STAT
      signaling in Southeast Asian ichthyosis patients
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Microbiome meta-analysis showed distinct microbial populations, decreases
      in commensal microbiota, and higher colonization by pathogenic species
      associated with CI; these were correlated with increased production of
      inflammatory cytokines and Th17- and JAK/STAT-signaling pathways in
      peripheral blood mononuclear cells.
    explanation: >-
      Directly supports microbiome dysbiosis as a congenital ichthyosis
      mechanism linked to inflammation and pathogenic colonization.
- name: Th17/JAK-STAT Inflammatory Activation
  description: >-
    Barrier and microbiome abnormalities in congenital ichthyosis are associated
    with increased inflammatory cytokines and Th17/JAK-STAT pathway activation.
  cell_types:
  - preferred_term: T-helper 17 cell
    term:
      id: CL:0000899
      label: T-helper 17 cell
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  - preferred_term: T-helper 17 type immune response
    term:
      id: GO:0072538
      label: T-helper 17 type immune response
    modifier: INCREASED
  - preferred_term: JAK-STAT signaling pathway
    term:
      id: GO:0007259
      label: cell surface receptor signaling pathway via JAK-STAT
    modifier: INCREASED
  downstream:
  - target: Erythroderma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Recurrent Skin Infections
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  evidence:
  - reference: DOI:10.1186/s40246-024-00603-x
    reference_title: Altered skin microbiome, inflammation, and JAK/STAT
      signaling in Southeast Asian ichthyosis patients
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Microbiome meta-analysis showed distinct microbial populations, decreases
      in commensal microbiota, and higher colonization by pathogenic species
      associated with CI; these were correlated with increased production of
      inflammatory cytokines and Th17- and JAK/STAT-signaling pathways in
      peripheral blood mononuclear cells.
    explanation: >-
      Supports inflammatory cytokine, Th17, and JAK-STAT activation downstream
      of congenital ichthyosis barrier and microbiome abnormalities.
phenotypes:
- category: Dermatological
  name: Ichthyosis
  diagnostic: true
  description: >-
    Generalized dry scaling of the skin is the shared phenotype across the
    inherited ichthyosis group.
  phenotype_term:
    preferred_term: Ichthyosis
    term:
      id: HP:0008064
      label: Ichthyosis
  evidence:
  - reference: DOI:10.1186/s40246-024-00603-x
    reference_title: Altered skin microbiome, inflammation, and JAK/STAT
      signaling in Southeast Asian ichthyosis patients
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients present with epidermal scaling, fissuring, chronic inflammation,
      and increased susceptibility to infections.
    explanation: >-
      Supports scaling as a central congenital ichthyosis phenotype.
- category: Dermatological
  name: Hyperkeratosis
  description: >-
    Thickened stratum corneum and retained scale contribute to the fish-scale
    appearance in multiple inherited ichthyosis subtypes.
  phenotype_term:
    preferred_term: Hyperkeratosis
    term:
      id: HP:0000962
      label: Hyperkeratosis
  evidence:
  - reference: clinicaltrials:NCT03041038
    reference_title: A Multicenter Study With a Randomized, Double-Blind,
      Placebo-Controlled Period, Followed by an Open-Label Maintenance Dosing
      Period to Evaluate the Efficacy and Safety of Secukinumab in Patients
      With Ichthyoses
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The ichthyoses are a group of lifelong genetic disorders which share
      characteristics of generalized skin thickening, scaling and underlying
      cutaneous inflammation.
    explanation: >-
      Supports skin thickening and scaling as core inherited ichthyosis
      phenotypes.
- category: Dermatological
  name: Erythroderma
  description: >-
    Diffuse erythema is prominent in several congenital ichthyosis presentations
    and varies by subtype.
  phenotype_term:
    preferred_term: Erythroderma
    term:
      id: HP:0001019
      label: Erythroderma
  evidence:
  - reference: PMID:38588653
    reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
      Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
      Features in 74 Italian Patients'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Seventy-four consecutive patients (mean age 11.0 years, range 0.1-48.8)
      affected with lamellar ichthyosis (50/74, 67.5%), congenital
      ichthyosiform erythroderma (18/74, 24.3%), harlequin ichthyosis (two/74,
      2.7%), and other minor ARCI subtypes (four/74, 5.4%) were enrolled.
    explanation: >-
      Directly supports erythroderma as part of the ARCI clinical spectrum.
- category: Dermatological
  name: Palmoplantar keratoderma
  description: >-
    Some inherited ichthyosis subtypes include abnormal thickening of the palms
    and soles.
  phenotype_term:
    preferred_term: Palmoplantar keratoderma
    term:
      id: HP:0000982
      label: Palmoplantar keratoderma
  evidence:
  - reference: PMID:38588653
    reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
      Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
      Features in 74 Italian Patients'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Among specific phenotypic features, psoriasis-like lesions as well as a
      trunk reticulate scale pattern and striated keratoderma were present in
      NIPAL4-mutated patients.
    explanation: >-
      Supports palmoplantar/striated keratoderma as a subtype-associated
      inherited ichthyosis feature.
- category: Dermatological
  name: Pruritus
  description: >-
    Itch is common in congenital ichthyosis cohorts and is consistent with
    inflamed, fissured, barrier-defective skin.
  phenotype_term:
    preferred_term: Pruritus
    term:
      id: HP:0000989
      label: Pruritus
- category: Dermatological
  name: Hypohidrosis
  description: >-
    Reduced sweating can occur in inherited ichthyosis and contributes to heat
    intolerance when thickened skin impairs normal thermoregulation.
  phenotype_term:
    preferred_term: Hypohidrosis
    term:
      id: HP:0000966
      label: Hypohidrosis
- category: Dermatological
  name: Recurrent Skin Infections
  description: >-
    Defective barrier function and dysbiotic skin colonization make recurrent
    skin infection a frequent complication of congenital ichthyosis.
  phenotype_term:
    preferred_term: Recurrent infections
    term:
      id: HP:0002719
      label: Recurrent infections
  evidence:
  - reference: DOI:10.1186/s40246-024-00603-x
    reference_title: Altered skin microbiome, inflammation, and JAK/STAT
      signaling in Southeast Asian ichthyosis patients
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients present with epidermal scaling, fissuring, chronic inflammation,
      and increased susceptibility to infections.
    explanation: >-
      Directly supports increased susceptibility to infections in congenital
      ichthyosis.
- category: Constitutional
  name: Heat Intolerance
  description: >-
    Heat intolerance can occur in inherited ichthyosis and is consistent with
    hypohidrosis and impaired skin barrier function.
  phenotype_term:
    preferred_term: Heat intolerance
    term:
      id: HP:0002046
      label: Heat intolerance
- category: Dermatological
  name: Alopecia
  description: >-
    Hair loss occurs in a subset of inherited ichthyosis patients, particularly
    in higher-severity TGM1- and ABCA12-associated ARCI.
  phenotype_term:
    preferred_term: Alopecia
    term:
      id: HP:0001596
      label: Alopecia
  evidence:
  - reference: PMID:38588653
    reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
      Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
      Features in 74 Italian Patients'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Alopecia, ectropion, and eclabium were significantly associated with TGM1
      and ABCA12 mutations, and large, thick, and brownish scales with TGM1
      mutations.
    explanation: >-
      Supports alopecia as a genotype-associated ARCI phenotype.
genetic:
- name: FLG
  association: Causative biallelic loss-of-function variants in ichthyosis vulgaris
  gene_term:
    preferred_term: FLG
    term:
      id: hgnc:3748
      label: FLG
  inheritance:
  - name: Autosomal semidominant inheritance
  evidence:
  - reference: DOI:10.3390/biomedicines12051112
    reference_title: Comprehensive Molecular Analysis of Disease-Related Genes
      as First-Tier Test for Early Diagnosis, Classification, and Management
      of Patients Affected by Nonsyndromic Ichthyosis
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Three patients had biallelic loss-of-function variants in FLG, whereas
      6/11 males were affected by X-linked ichthyosis.
    explanation: >-
      Supports FLG loss of function as the molecular basis for an inherited
      ichthyosis subtype in this cohort.
- name: STS
  association: Causative steroid sulfatase deficiency in X-linked ichthyosis
  gene_term:
    preferred_term: STS
    term:
      id: hgnc:11425
      label: STS
  inheritance:
  - name: X-linked recessive
  evidence:
  - reference: DOI:10.3390/biomedicines12051112
    reference_title: Comprehensive Molecular Analysis of Disease-Related Genes
      as First-Tier Test for Early Diagnosis, Classification, and Management
      of Patients Affected by Nonsyndromic Ichthyosis
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Three patients had biallelic loss-of-function variants in FLG, whereas
      6/11 males were affected by X-linked ichthyosis.
    explanation: >-
      Supports X-linked ichthyosis representation in the cohort; STS is the
      canonical steroid-sulfatase gene for this subtype.
- name: TGM1
  association: Causative biallelic pathogenic variants in autosomal recessive
    congenital ichthyosis
  gene_term:
    preferred_term: TGM1
    term:
      id: hgnc:11777
      label: TGM1
  inheritance:
  - name: Autosomal recessive
  evidence:
  - reference: PMID:38588653
    reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
      Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
      Features in 74 Italian Patients'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in
      18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%),
      ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1,
      and SDR9C7 in 1 patient each (1.4%).
    explanation: >-
      Supports TGM1 as a common causative ARCI gene.
- name: ALOX12B
  association: Causative biallelic pathogenic variants in autosomal recessive
    congenital ichthyosis
  gene_term:
    preferred_term: ALOX12B
    term:
      id: hgnc:430
      label: ALOX12B
  inheritance:
  - name: Autosomal recessive
  evidence:
  - reference: PMID:38588653
    reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
      Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
      Features in 74 Italian Patients'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in
      18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%),
      ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1,
      and SDR9C7 in 1 patient each (1.4%).
    explanation: >-
      Supports ALOX12B as a common causative ARCI gene.
- name: ABCA12
  association: Causative biallelic pathogenic variants in autosomal recessive
    congenital ichthyosis, including harlequin ichthyosis
  gene_term:
    preferred_term: ABCA12
    term:
      id: hgnc:14637
      label: ABCA12
  inheritance:
  - name: Autosomal recessive
  evidence:
  - reference: PMID:38588653
    reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
      Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
      Features in 74 Italian Patients'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in
      18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%),
      ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1,
      and SDR9C7 in 1 patient each (1.4%).
    explanation: >-
      Supports ABCA12 as a recurrent causative ARCI gene in the cohort.
treatments:
- name: Topical emollients and keratolytic/supportive therapy
  description: >-
    Barrier-directed topical care with emollients and keratolytics is standard
    symptomatic management for scaling, fissuring, and dryness across inherited
    ichthyosis subtypes.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  target_phenotypes:
  - preferred_term: Ichthyosis
    term:
      id: HP:0008064
      label: Ichthyosis
- name: Retinoid pharmacotherapy
  description: >-
    Systemic or topical retinoid therapy can reduce severe scaling and
    hyperkeratosis, including topical isotretinoin TMB-001 studied in the
    CONTROL trial.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: isotretinoin
      term:
        id: CHEBI:6067
        label: isotretinoin
  target_phenotypes:
  - preferred_term: Ichthyosis
    term:
      id: HP:0008064
      label: Ichthyosis
  evidence:
  - reference: clinicaltrials:NCT04154293
    reference_title: A Randomized, Parallel, Double-Blind, Vehicle Controlled
      Study to Evaluate the Safety and Efficacy of Two Concentrations of Topical
      TMB-001 for the Treatment of Congenital Ichthyosis
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The purpose of this study is to investigate the efficacy and safety of
      two concentrations of topically applied ointment formulation of
      isotretinoin called TMB-001 (0.05% and 0.1% isotretinoin) in subjects 9
      years of age and older for the treatment of congenital ichthyosis (CI),
      including recessive X-linked ichthyosis (RXLI) and autosomal recessive
      congenital ichthyosis-lamellar ichthyosis (ARCI-LI) subtypes.
    explanation: >-
      Supports topical isotretinoin TMB-001 as a congenital ichthyosis therapy
      evaluated in a randomized clinical study.
- name: Topical TGM1 gene therapy
  description: >-
    KB105 is a topical HSV-1 vector expressing TGM1 under clinical investigation
    for TGM1-deficient autosomal recessive congenital ichthyosis.
  treatment_term:
    preferred_term: gene therapy
    term:
      id: MAXO:0001001
      label: gene therapy
  target_mechanisms:
  - target: Epidermal Lipid Metabolism Defect
    treatment_effect: RESTORES
    description: >-
      Topical TGM1 expression is intended to restore deficient transglutaminase
      1 activity in affected skin.
  evidence:
  - reference: clinicaltrials:NCT04047732
    reference_title: A Phase I/II Clinical Trial of Topical KB105, a
      Replication-incompetent, Non-integrating HSV-1 Vector Expressing Human
      Transglutaminase 1 (TGM1) for the Treatment of TGM1-deficient Autosomal
      Recessive Congenital Ichthyosis (ARCI)
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This study is an intra-patient comparison of KB105 and placebo-administered
      Target Areas. The primary objectives of this study are to evaluate safety
      and Investigator Global Assessment (IGA) scale improvement of topically
      administered KB105.
    explanation: >-
      Supports clinical testing of topical KB105 for TGM1-deficient ARCI.
- name: IL-17A-targeting biologic therapy
  description: >-
    Secukinumab has been studied as a mechanism-based immunomodulatory approach
    for ichthyoses with cutaneous inflammation and IL-17 pathway activation.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: Secukinumab
      term:
        id: NCIT:C152315
        label: Secukinumab
  target_mechanisms:
  - target: Th17/JAK-STAT Inflammatory Activation
    treatment_effect: INHIBITS
    description: >-
      IL-17A blockade is intended to reduce inflammatory signaling in selected
      ichthyosis patients with immune activation.
  evidence:
  - reference: clinicaltrials:NCT03041038
    reference_title: A Multicenter Study With a Randomized, Double-Blind,
      Placebo-Controlled Period, Followed by an Open-Label Maintenance Dosing
      Period to Evaluate the Efficacy and Safety of Secukinumab in Patients
      With Ichthyoses
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The ichthyoses are a group of lifelong genetic disorders which share
      characteristics of generalized skin thickening, scaling and underlying
      cutaneous inflammation.
    explanation: >-
      Supports inflammatory pathway targeting in ichthyoses, while the trial is
      not specific to all inherited ichthyosis subtypes.
prevalence:
- population: Worldwide ARCI
  notes: >-
    Falcon extracted an ARCI prevalence range of about 1:100,000 to 1:300,000
    worldwide from the 2024 inherited ichthyosis research set.
- population: Male newborns with X-linked ichthyosis
  notes: >-
    Falcon extracted an X-linked ichthyosis prevalence range of about 1:2,000
    to 1:6,000 male newborns from the 2024 inherited ichthyosis research set.
clinical_trials:
- name: NCT04047732
  phase: PHASE_I
  notes: >-
    ClinicalTrials.gov lists this as a combined Phase I/II study; mapped to
    PHASE_I because the schema accepts a single phase value.
  description: >-
    Phase I/II topical KB105 intra-patient comparison trial for
    TGM1-deficient ARCI.
  evidence:
  - reference: clinicaltrials:NCT04047732
    reference_title: A Phase I/II Clinical Trial of Topical KB105, a
      Replication-incompetent, Non-integrating HSV-1 Vector Expressing Human
      Transglutaminase 1 (TGM1) for the Treatment of TGM1-deficient Autosomal
      Recessive Congenital Ichthyosis (ARCI)
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This study is an intra-patient comparison of KB105 and placebo-administered
      Target Areas. The primary objectives of this study are to evaluate safety
      and Investigator Global Assessment (IGA) scale improvement of topically
      administered KB105.
    explanation: >-
      Supports this trial as topical KB105 clinical testing in TGM1-deficient
      ARCI.
- name: NCT05735158
  phase: PHASE_II
  description: >-
    Randomized placebo-controlled topical KB105 study in children and adults
    with ARCI.
  evidence:
  - reference: clinicaltrials:NCT05735158
    reference_title: A Phase 2, Randomized, Placebo-controlled Study of Topical
      KB105, a Replication-defective, Non-integrating HSV-1 Vector Expressing
      Human Transglutaminase 1 (TGM1) for the Treatment of TGM1-deficient
      Autosomal Recessive Congenital Ichthyosis (ARCI)
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      KB105-02 is an intrasubject randomized, placebo-controlled, double-blind
      study to evaluate the safety and efficacy of KB105 in children and adults
      with autosomal recessive congenital ichthyosis (ARCI).
    explanation: >-
      Supports this as a randomized phase 2 ARCI KB105 trial record.
- name: NCT03041038
  phase: PHASE_II
  description: >-
    Phase 2 secukinumab trial in ichthyoses testing IL-17A-targeted
    immunomodulation for inflammatory skin thickening and scaling.
  evidence:
  - reference: clinicaltrials:NCT03041038
    reference_title: A Multicenter Study With a Randomized, Double-Blind,
      Placebo-Controlled Period, Followed by an Open-Label Maintenance Dosing
      Period to Evaluate the Efficacy and Safety of Secukinumab in Patients
      With Ichthyoses
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The ichthyoses are a group of lifelong genetic disorders which share
      characteristics of generalized skin thickening, scaling and underlying
      cutaneous inflammation.
    explanation: >-
      Supports this trial as relevant to inflammatory ichthyosis biology,
      although not specific to every inherited ichthyosis subtype.
datasets:
references:
- reference: DOI:10.1007/s13555-023-00923-1
  title: Topical Isotretinoin (TMB-001) Treatment for 12 Weeks Did Not Result in
    Clinically Relevant Laboratory Abnormalities in Participants with Congenital
    Ichthyosis in the Phase 2b CONTROL Study
  found_in:
  - Inherited_Ichthyosis-deep-research-falcon.md
  findings:
  - statement: Topical Isotretinoin (TMB-001) Treatment for 12 Weeks Did Not 
      Result in Clinically Relevant Laboratory Abnormalities in Participants 
      with Congenital Ichthyosis in the Phase 2b CONTROL Study
    supporting_text: Topical Isotretinoin (TMB-001) Treatment for 12 Weeks Did 
      Not Result in Clinically Relevant Laboratory Abnormalities in Participants
      with Congenital Ichthyosis in the Phase 2b CONTROL Study
- reference: DOI:10.1038/s41572-022-00412-3
  title: Ichthyosis
  found_in:
  - Inherited_Ichthyosis-deep-research-falcon.md
  findings:
  - statement: Ichthyosis
    supporting_text: Ichthyosis
- reference: DOI:10.1159/000536366
  title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses: Association
    of Genotype with Disease Severity, Phenotypic, and Ultrastructural Features in
    74 Italian Patients'
  found_in:
  - Inherited_Ichthyosis-deep-research-falcon.md
  findings:
  - statement: Autosomal recessive congenital ichthyoses (ARCIs) are a 
      clinically heterogeneous group of keratinization disorders characterized 
      by generalized skin scaling due to mutations in at least 12 genes.
    supporting_text: Autosomal recessive congenital ichthyoses (ARCIs) are a 
      clinically heterogeneous group of keratinization disorders characterized 
      by generalized skin scaling due to mutations in at least 12 genes.
    evidence:
    - reference: DOI:10.1159/000536366
      reference_title: 'Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses:
        Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural
        Features in 74 Italian Patients'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Autosomal recessive congenital ichthyoses (ARCIs) are a 
        clinically heterogeneous group of keratinization disorders characterized
        by generalized skin scaling due to mutations in at least 12 genes.
      explanation: Deep research cited this publication as relevant literature 
        for Inherited Ichthyosis.
- reference: DOI:10.1186/s40246-024-00603-x
  title: Altered skin microbiome, inflammation, and JAK/STAT signaling in 
    Southeast Asian ichthyosis patients
  found_in:
  - Inherited_Ichthyosis-deep-research-falcon.md
  findings:
  - statement: Congenital ichthyosis (CI) is a collective group of rare 
      hereditary skin disorders.
    supporting_text: Congenital ichthyosis (CI) is a collective group of rare 
      hereditary skin disorders.
    evidence:
    - reference: DOI:10.1186/s40246-024-00603-x
      reference_title: Altered skin microbiome, inflammation, and JAK/STAT 
        signaling in Southeast Asian ichthyosis patients
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Congenital ichthyosis (CI) is a collective group of rare 
        hereditary skin disorders.
      explanation: Deep research cited this publication as relevant literature 
        for Inherited Ichthyosis.
- reference: DOI:10.2340/actadv.v105.41100
  title: 'The Clinical Spectrum of Rare Inherited Ichthyosis in China: A Review of
    Thirty-five Cases'
  found_in:
  - Inherited_Ichthyosis-deep-research-falcon.md
  findings:
  - statement: Inherited ichthyosis comprises a spectrum of genetic disorders 
      related to over 50 pathogenic genes.
    supporting_text: Inherited ichthyosis comprises a spectrum of genetic 
      disorders related to over 50 pathogenic genes.
    evidence:
    - reference: DOI:10.2340/actadv.v105.41100
      reference_title: 'The Clinical Spectrum of Rare Inherited Ichthyosis in China:
        A Review of Thirty-five Cases'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Inherited ichthyosis comprises a spectrum of genetic disorders 
        related to over 50 pathogenic genes.
      explanation: Deep research cited this publication as relevant literature 
        for Inherited Ichthyosis.
- reference: DOI:10.3390/biomedicines12051112
  title: Comprehensive Molecular Analysis of Disease-Related Genes as First-Tier
    Test for Early Diagnosis, Classification, and Management of Patients 
    Affected by Nonsyndromic Ichthyosis
  found_in:
  - Inherited_Ichthyosis-deep-research-falcon.md
  findings:
  - statement: Inherited ichthyoses are a group of clinically and genetically 
      heterogeneous rare disorders of skin keratinization with overlapping 
      phenotypes.
    supporting_text: Inherited ichthyoses are a group of clinically and 
      genetically heterogeneous rare disorders of skin keratinization with 
      overlapping phenotypes.
    evidence:
    - reference: DOI:10.3390/biomedicines12051112
      reference_title: Comprehensive Molecular Analysis of Disease-Related Genes
        as First-Tier Test for Early Diagnosis, Classification, and Management 
        of Patients Affected by Nonsyndromic Ichthyosis
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Inherited ichthyoses are a group of clinically and genetically 
        heterogeneous rare disorders of skin keratinization with overlapping 
        phenotypes.
      explanation: Deep research cited this publication as relevant literature 
        for Inherited Ichthyosis.
- reference: DOI:10.61577/amsd.2023.100004
  title: Molecular genetics and pathogenesis of ichthyosis
  found_in:
  - Inherited_Ichthyosis-deep-research-falcon.md
  findings:
  - statement: Molecular genetics and pathogenesis of ichthyosis
    supporting_text: Molecular genetics and pathogenesis of ichthyosis
📚

References & Deep Research

References

7
DOI:10.1007/s13555-023-00923-1
Topical Isotretinoin (TMB-001) Treatment for 12 Weeks Did Not Result in Clinically Relevant Laboratory Abnormalities in Participants with Congenital Ichthyosis in the Phase 2b CONTROL Study
1 finding
Topical Isotretinoin (TMB-001) Treatment for 12 Weeks Did Not Result in Clinically Relevant Laboratory Abnormalities in Participants with Congenital Ichthyosis in the Phase 2b CONTROL Study
"Topical Isotretinoin (TMB-001) Treatment for 12 Weeks Did Not Result in Clinically Relevant Laboratory Abnormalities in Participants with Congenital Ichthyosis in the Phase 2b CONTROL Study"
1 finding
Ichthyosis
"Ichthyosis"
DOI:10.1159/000536366
Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses: Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural Features in 74 Italian Patients
1 finding
Autosomal recessive congenital ichthyoses (ARCIs) are a clinically heterogeneous group of keratinization disorders characterized by generalized skin scaling due to mutations in at least 12 genes.
"Autosomal recessive congenital ichthyoses (ARCIs) are a clinically heterogeneous group of keratinization disorders characterized by generalized skin scaling due to mutations in at least 12 genes."
Show evidence (1 reference)
DOI:10.1159/000536366 SUPPORT Human Clinical
"Autosomal recessive congenital ichthyoses (ARCIs) are a clinically heterogeneous group of keratinization disorders characterized by generalized skin scaling due to mutations in at least 12 genes."
Deep research cited this publication as relevant literature for Inherited Ichthyosis.
DOI:10.1186/s40246-024-00603-x
Altered skin microbiome, inflammation, and JAK/STAT signaling in Southeast Asian ichthyosis patients
1 finding
Congenital ichthyosis (CI) is a collective group of rare hereditary skin disorders.
"Congenital ichthyosis (CI) is a collective group of rare hereditary skin disorders."
Show evidence (1 reference)
DOI:10.1186/s40246-024-00603-x SUPPORT Human Clinical
"Congenital ichthyosis (CI) is a collective group of rare hereditary skin disorders."
Deep research cited this publication as relevant literature for Inherited Ichthyosis.
DOI:10.2340/actadv.v105.41100
The Clinical Spectrum of Rare Inherited Ichthyosis in China: A Review of Thirty-five Cases
1 finding
Inherited ichthyosis comprises a spectrum of genetic disorders related to over 50 pathogenic genes.
"Inherited ichthyosis comprises a spectrum of genetic disorders related to over 50 pathogenic genes."
Show evidence (1 reference)
DOI:10.2340/actadv.v105.41100 SUPPORT Human Clinical
"Inherited ichthyosis comprises a spectrum of genetic disorders related to over 50 pathogenic genes."
Deep research cited this publication as relevant literature for Inherited Ichthyosis.
DOI:10.3390/biomedicines12051112
Comprehensive Molecular Analysis of Disease-Related Genes as First-Tier Test for Early Diagnosis, Classification, and Management of Patients Affected by Nonsyndromic Ichthyosis
1 finding
Inherited ichthyoses are a group of clinically and genetically heterogeneous rare disorders of skin keratinization with overlapping phenotypes.
"Inherited ichthyoses are a group of clinically and genetically heterogeneous rare disorders of skin keratinization with overlapping phenotypes."
Show evidence (1 reference)
DOI:10.3390/biomedicines12051112 SUPPORT Human Clinical
"Inherited ichthyoses are a group of clinically and genetically heterogeneous rare disorders of skin keratinization with overlapping phenotypes."
Deep research cited this publication as relevant literature for Inherited Ichthyosis.
DOI:10.61577/amsd.2023.100004
Molecular genetics and pathogenesis of ichthyosis
1 finding
Molecular genetics and pathogenesis of ichthyosis
"Molecular genetics and pathogenesis of ichthyosis"

Deep Research

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Disease Characteristics Research Template
Edison Scientific Literature 33 citations 2026-05-07T12:21:30.795708

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

  • Disease Name: Inherited Ichthyosis
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Inherited Ichthyosis covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

  • What is the disease? Provide a concise overview.
  • What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
  • What are the common synonyms and alternative names?
  • Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

  • Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
  • Risk Factors:

    Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases

  • Genetic risk factors (causal variants, susceptibility loci, modifier genes)
  • Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
  • Protective Factors:

    Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases

  • Genetic protective factors (protective variants, modifier alleles)
  • Environmental protective factors (diet, lifestyle, exposures that reduce risk)
  • Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

    Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

  • Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

    Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene

  • Pathogenic Variants:
  • Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
  • Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
  • Variant type/class (missense, frameshift, nonsense, splice-site, structural)
  • Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
  • Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
  • Functional consequences (loss of function, gain of function, dominant negative)
  • Modifier Genes: Genes that modify disease severity or expression
  • Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

    Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

  • Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

    Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases

  • Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

    Search first: CDC databases, WHO, PubMed, NHANES

  • Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

    Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

  • Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

    Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc

  • Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

    Search first: Gene Ontology (GO), Reactome, KEGG, PubMed

  • Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

    Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold

  • Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

    Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA

  • Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

    Search first: ImmPort, Immunome Database, IEDB, Gene Ontology

  • Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

    Search first: PubMed, Gene Ontology, Reactome

  • Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

    Search first: BRENDA, UniProt, KEGG, OMIM, PubMed

  • Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Molecular Profiling (if available):
  • Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
  • Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
  • Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
  • Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
  • Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
  • Advanced Technologies (if applicable):
  • Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
  • Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
  • Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
  • Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

  • Organ Level:
  • Primary organs directly affected
  • Secondary organ involvement (complications, secondary effects)
  • Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

    Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT

  • Tissue and Cell Level:
  • Specific tissue types affected (epithelial, connective, muscle, nervous)
  • Specific cell populations targeted (with Cell Ontology terms)

    Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB

  • Subcellular Level:
  • Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

    Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas

  • Localization:
  • Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
  • Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

  • Onset:
  • Typical age of onset (congenital, pediatric, adult, geriatric)
  • Onset pattern (acute, subacute, chronic, insidious)

    Search first: OMIM, Orphanet, HPO, PubMed

  • Progression:
  • Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
  • Progression rate (rapid, slow, variable)
  • Disease course pattern (episodic, relapsing-remitting, progressive, stable)
  • Disease duration (self-limited, chronic lifelong)

    Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM

  • Patterns:
  • Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
  • Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

  • Epidemiology:
  • Prevalence (cases per 100,000 at given time)
  • Incidence (new cases per 100,000 per year)

    Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries

  • For Genetic Etiology:
  • Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
  • Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
  • Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
  • Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
  • Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
  • Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
  • Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
  • Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
  • Population Demographics:
  • Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
  • Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
  • Geographic distribution of specific variants
  • Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
  • Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

  • Clinical Tests:
  • Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
  • Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
  • Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
  • Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
  • Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
  • Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
  • Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
  • Genetic Testing:

    Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen

  • Overview of recommended genetic testing approach
  • Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
  • Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
  • Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
  • Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
  • Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
  • Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
  • FISH > Search first: ClinVar, cytogenetics databases, PubMed
  • Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
  • Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
  • Omics-Based Diagnostics (if applicable):
  • RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
  • Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
  • Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
  • Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
  • Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
  • Clinical Criteria:
  • Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
  • Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
  • Screening:
  • Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

  • Survival and Mortality:
  • Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
  • Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
  • Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
  • Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
  • Morbidity and Function:
  • Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
  • Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
  • Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
  • Disease Course:
  • Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
  • Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
  • Prediction:
  • Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
  • Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

  • Pharmacotherapy:
  • Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
  • Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
  • Advanced Therapeutics:
  • Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
  • Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
  • RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
  • Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
  • Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
  • Surgical and Interventional:
  • Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
  • Supportive and Rehabilitative:
  • Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
  • Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
  • Experimental:
  • Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
  • Treatment Outcomes:
  • Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
  • Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
  • Treatment Strategy:
  • Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
  • Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
  • Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

  • Prevention Levels:
  • Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
  • Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
  • Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
  • Immunization: Vaccine strategies (if applicable)

    Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database

  • Screening and Early Detection:
  • Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
  • Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
  • Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
  • Behavioral Interventions: Lifestyle modifications to reduce risk

    Search first: CDC, WHO, behavioral intervention databases, Cochrane Library

  • Counseling: Genetic counseling (risk assessment, family planning guidance)

    Search first: NSGC resources, ACMG guidelines, GeneReviews

  • Public Health:
  • Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
  • Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
  • Prophylaxis: Preventive medications or procedures

    Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

  • Taxonomy: Species affected (with NCBI Taxon identifiers)

    Search first: NCBI Taxonomy

  • Breed: Specific breeds affected (with VBO identifiers if applicable)

    Search first: VBO (Vertebrate Breed Ontology)

  • Gene: Orthologous genes in other species (with NCBI Gene IDs)

    Search first: NCBI Gene

  • Natural Disease:
  • Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
  • Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
  • Comparative Biology:
  • Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
  • Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
  • Transmission (if applicable):
  • Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
  • Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

  • Model Types:
  • Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
  • Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
  • Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
  • Genetic Models:
  • Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
  • Model Characteristics:
  • Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
  • Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
  • Applications:
  • Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
  • Resources:
  • Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

  • Cite primary literature (PMID preferred) for all mechanistic and clinical claims
  • Prioritize recent reviews and landmark papers
  • Include direct quotes from abstracts where possible to support key statements
  • Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Inherited Ichthyosis — Disease Characteristics Research Report (2023–2024 emphasis)

Target disease

Disease name: Inherited ichthyosis (collective term; includes congenital ichthyoses and other Mendelian disorders of cornification)

Scope note: “Inherited ichthyosis” is not a single disorder but a heterogeneous group of Mendelian disorders of cornification with shared core features of generalized scaling/hyperkeratosis and barrier dysfunction, spanning non‑syndromic (skin-limited) and syndromic forms. (xiang2025theclinicalspectrum pages 1-2, fioretti2024comprehensivemolecularanalysis pages 1-2, panda2025moleculargeneticsand pages 2-3)

MONDO ID: Not retrieved in the available tool-evidence corpus; cannot be asserted from current sources.

Key synonyms / related terms (commonly used in the retrieved sources): - Congenital ichthyosis / congenital ichthyoses (CI) (marathe2023topicalisotretinoin(tmb001) pages 1-3, ho2024alteredskinmicrobiome pages 2-4) - Autosomal recessive congenital ichthyosis (ARCI) including lamellar ichthyosis (LI), congenital ichthyosiform erythroderma (CIE), harlequin ichthyosis (HI), self‑improving collodion ichthyosis (SICI) (fioretti2024comprehensivemolecularanalysis pages 1-2, fioretti2024comprehensivemolecularanalysis pages 2-3) - X‑linked ichthyosis / X‑linked recessive ichthyosis (XLI/XLRI) (fioretti2024comprehensivemolecularanalysis pages 1-2, marathe2023topicalisotretinoin(tmb001) pages 1-3)

Data provenance: The evidence used here is aggregated from peer‑reviewed cohort studies, reviews, and ClinicalTrials.gov registry records (not individual EHR-level data). (fioretti2024comprehensivemolecularanalysis pages 1-2, diociaiuti2024crosssectionalstudyon pages 4-5, marathe2023topicalisotretinoin(tmb001) pages 1-3, ho2024alteredskinmicrobiome pages 2-4)

1. Disease information

Overview and current understanding

Inherited ichthyoses are genetic disorders of keratinization/cornification characterized clinically by persistent scaling and hyperkeratosis, often with erythema, fissuring, pruritus, and susceptibility to infection, reflecting defective epidermal barrier function. (fioretti2024comprehensivemolecularanalysis pages 1-2, panda2025moleculargeneticsand pages 2-3, ho2024alteredskinmicrobiome pages 2-4)

A 2024 cohort paper summarizes the diagnostic principle that clinical phenotype and family history guide suspicion, but molecular diagnosis is required for correct classification: “only the identification of the genetic defect allows the correct classification.” (Fioretti 2024, Biomedicines, published May 2024; https://doi.org/10.3390/biomedicines12051112) (fioretti2024comprehensivemolecularanalysis pages 1-2)

Key identifiers

From the retrieved evidence set, explicit code mappings (ICD‑10/ICD‑11/MeSH/OMIM/Orphanet/MONDO) were not captured as structured fields. An ICD‑10 anchor frequently used clinically for congenital ichthyosis is Q80.* (not directly supported by the retrieved evidence, so not asserted).

Evidence limitation: Because OMIM/Orphanet/MONDO/MeSH identifiers are not present in the retrieved full texts/chunks, this report cannot provide verified identifier lists without additional database retrieval.

2. Etiology

2.1 Disease causal factors

Primary cause: Germline pathogenic variants in genes required for epidermal barrier formation, cornified envelope assembly, keratin cytoskeleton integrity, and epidermal lipid metabolism. In multiple sources, inherited ichthyosis is described as involving >50 genes. (xiang2025theclinicalspectrum pages 1-2, fioretti2024comprehensivemolecularanalysis pages 1-2, panda2025moleculargeneticsand pages 2-3)

Key genetic etiologies highlighted in recent clinical cohorts and reviews: - ARCI genes: TGM1, ALOX12B, CYP4F22, ABCA12, ALOXE3, NIPAL4, CERS3, PNPLA1, SDR9C7 (diociaiuti2024crosssectionalstudyon pages 4-5, diociaiuti2024crosssectionalstudyon media 464df4f0) - Common ichthyosis types: FLG (ichthyosis vulgaris), STS (X‑linked ichthyosis), ABCA12 (harlequin ichthyosis), TGM1 (lamellar ichthyosis) (panda2025moleculargeneticsand pages 3-4, fioretti2024comprehensivemolecularanalysis pages 1-2)

2.2 Risk factors

  • Genetic: Having biallelic pathogenic variants in ARCI genes (autosomal recessive), or hemizygous pathogenic variants/deletions for X‑linked forms; positive family history and consanguinity increase risk for recessive forms (the latter is implied by recessive genetics; explicit consanguinity statistics were not retrieved in the current evidence set). (fioretti2024comprehensivemolecularanalysis pages 2-3)
  • Clinical complication risk: High burden of microbial infections is common in congenital ichthyosis cohorts (e.g., 94.4% in one study), consistent with barrier defect–mediated infection susceptibility. (ho2024alteredskinmicrobiome pages 2-4)

2.3 Protective factors and GxE

No protective genetic variants or explicit gene–environment interaction studies were retrieved in the available corpus; therefore, no evidence-based protective factors can be asserted.

3. Phenotypes

3.1 Core phenotypes (with recent frequency data)

A 2024 Italian ARCI cohort (n=74) quantified several common features (selected examples): - Hypohidrosis: 54/74 (73.0%) (HPO suggestion: Hypohidrosis [HP:0000966]) (diociaiuti2024crosssectionalstudyon pages 4-5) - Heat intolerance: 46/74 (62.2%) (HPO: Heat intolerance [HP:0002046]) (diociaiuti2024crosssectionalstudyon pages 4-5) - Ear deformities: 22/74 (29.7%) (HPO: Abnormality of the ear [HP:0000598]) (diociaiuti2024crosssectionalstudyon pages 4-5) - Alopecia: 16/74 (21.6%) (HPO: Alopecia [HP:0001596]) (diociaiuti2024crosssectionalstudyon pages 4-5)

A 2024 Southeast Asian congenital ichthyosis study (n=36) reported very high symptom/complication burden: - Hyperkeratosis: 100% (HPO: Hyperkeratosis [HP:0000962]) - Itch (pruritus): 97.2% (HPO: Pruritus [HP:0000989]) - Microbial infection: 94.4% (HPO: Recurrent infections [HP:0002719] or Skin infection [HP:0001045]) - Erythroderma: 72.2% (HPO: Erythroderma [HP:0001019]) (ho2024alteredskinmicrobiome pages 2-4)

3.2 Phenotype characteristics (onset, progression)

  • Many subtypes are congenital or present in the first months of life, including collodion membrane presentations in ARCI. In a 2024 diagnostic cohort, 6/17 were born encased in a collodion membrane (3 improved after shedding), while 11/17 had scaling at birth or in the first month. (fioretti2024comprehensivemolecularanalysis pages 2-3)
  • Course is typically chronic, with severity varying by genotype and subtype (e.g., higher mean severity scores in TGM1 and ABCA12 groups vs other ARCI genes). (diociaiuti2024crosssectionalstudyon pages 4-5, diociaiuti2024crosssectionalstudyon media 464df4f0)

3.3 Quality of life (QoL)

  • Congenital ichthyosis is consistently described as having substantial QoL impact, with severe itch and complications; one prospective qualitative study (NCT05610306) specifically targeted biological/psychological/social impacts and care gaps in adults ≥30 years with congenital ichthyosis. (NCT05610306 chunk 1)
  • A 2024 congenital ichthyosis cohort study reported mental health difficulty in 53% (19/36) of patients, emphasizing psychosocial burden. (ho2024alteredskinmicrobiome pages 2-4)

4. Genetic / molecular information

4.1 Causal genes (high-confidence examples from recent cohorts)

ARCI (example gene distribution in a 2024 Italian cohort, n=74): - TGM1: 18/74 (24.3%) - ALOX12B: 18/74 (24.3%) - CYP4F22: 12/74 (16.2%) - ABCA12: 9/74 (12.2%) - ALOXE3: 7/74 (9.5%) - NIPAL4: 7/74 (9.5%) - CERS3 / PNPLA1 / SDR9C7: 1/74 each (1.4%) (diociaiuti2024crosssectionalstudyon pages 4-5, diociaiuti2024crosssectionalstudyon media 464df4f0)

Visual evidence (gene frequencies and severity scores): (diociaiuti2024crosssectionalstudyon media 464df4f0)

4.2 Pathogenic variant classes and consequences

Across cohorts, variant classes include SNVs/indels and structural variants (e.g., microduplications in TGM1 and microdeletions affecting CYP4F22 and NIPAL4 in the Italian ARCI study). (diociaiuti2024crosssectionalstudyon pages 4-5)

Mechanistic consequence examples (review-level): - X‑linked ichthyosis: STS deficiency leading to cholesterol sulfate accumulation and barrier disruption (review summary). (panda2025moleculargeneticsand pages 1-2, panda2025moleculargeneticsand pages 2-3)

Direct mechanistic quote (review-level framing): “The disturbance in the epidermal barrier function is at the core of ichthyosis pathogenesis.” (panda2025moleculargeneticsand pages 2-3)

4.3 Modifier genes, epigenetics

No modifier-gene or epigenetic datasets specific to inherited ichthyosis were retrieved in the current corpus.

5. Environmental information

Inherited ichthyosis is primarily genetic. Environmental factors in the retrieved sources are mainly relevant to complications and management (e.g., infection risk and wound care). A detailed toxin/lifestyle exposure literature was not retrieved; thus no evidence-based environmental risk factor list is provided.

6. Mechanism / pathophysiology

6.1 Barrier defect → inflammation → infection susceptibility

A mechanistic chain supported by 2024 data: 1) Germline variants in barrier/cornification genes and lipid metabolism genes → 2) Altered epidermal structure and barrier permeability → 3) Dysbiosis with reduced commensals and increased pathogenic colonization → 4) Systemic and cutaneous immune activation (Th17/Th2 and JAK/STAT signatures) → 5) Clinical manifestations: scaling/hyperkeratosis, pruritus, infections, impaired wound healing.

The 2024 Southeast Asian study explicitly links microbiome changes and immune signaling: “Microbiome meta-analysis revealed distinct microbial populations, reduced commensal microbiota, and higher colonization by pathogenic species. This correlated with increased production of inflammatory cytokines, including Th17 and JAK/STAT signaling, in peripheral blood mononuclear cells.” (Ho 2024, Human Genomics, Apr 2024; https://doi.org/10.1186/s40246-024-00603-x) (ho2024alteredskinmicrobiome pages 1-2)

Additional quantitative immuno-microbiome findings include elevated neutrophils across congenital ichthyosis clusters and increased STAT3 phosphorylation (pY705) in several dysbiosis clusters, consistent with JAK/STAT pathway activation. (ho2024alteredskinmicrobiome pages 10-13)

6.2 Cell types (CL) and GO terms (suggestions)

Based on inflammation and barrier biology reported: - Cell types (CL term suggestions): - Keratinocyte (CL:0000312) - Neutrophil (CL:0000775) - CD4-positive, alpha-beta T cell (CL:0000624) including Th17 and Th2 subsets - Peripheral blood mononuclear cell (broad category; not a single CL type)

  • GO biological process term suggestions:
  • Keratinization (GO:0031424)
  • Epidermis development (GO:0008544)
  • Skin barrier establishment (GO:0061436)
  • Defense response to bacterium (GO:0042742)
  • IL‑17 signaling pathway (GO:0038111)
  • JAK‑STAT cascade (GO:0007259)

6.3 Model organism / experimental mechanism note

A review source notes that SMS2 knockout in mice produced an ichthyotic phenotype with epidermal hyperplasia and hyperkeratosis, supporting lipid pathway involvement in barrier integrity. (panda2025moleculargeneticsand pages 2-3)

7. Anatomical structures affected

Organ/tissue level

  • Primary: skin/epidermis (UBERON suggestion: skin UBERON:0002097; epidermis UBERON:0001003).
  • Common secondary involvement in cohorts includes wounds/infections and complications such as sepsis in severe subtypes. In the 2024 congenital ichthyosis cohort, lethal infant sepsis occurred in 6 cases (4 HI, 1 LI, 1 EI). (ho2024alteredskinmicrobiome pages 2-4)

Subcellular/cellular compartments (GO cellular component suggestions)

  • Cornified envelope (GO:0001533)
  • Keratin filament (GO:0045095)
  • Lamellar body (GO:0042599) (suggested by ARCI ultrastructural discussion context; direct GO mapping not explicitly provided in the evidence corpus)

8. Temporal development

  • Onset: Many forms are congenital/early infancy, including collodion membrane presentations in ARCI (see diagnostic cohort description). (fioretti2024comprehensivemolecularanalysis pages 2-3)
  • Course: Chronic lifelong disease with variable severity, influenced by genotype; a 2024 ARCI cohort demonstrated gene-associated severity differences (e.g., higher mean severity in TGM1 vs CYP4F22). (diociaiuti2024crosssectionalstudyon pages 4-5, diociaiuti2024crosssectionalstudyon media 464df4f0)

9. Inheritance and population

Inheritance patterns

  • ARCI is typically autosomal recessive with biallelic variants in barrier/lipid pathway genes (e.g., TGM1, ALOX12B). (diociaiuti2024crosssectionalstudyon pages 4-5, fioretti2024comprehensivemolecularanalysis pages 2-3)
  • X‑linked ichthyosis affects males with X‑linked STS involvement (XLI/XLRI). (fioretti2024comprehensivemolecularanalysis pages 1-2, marathe2023topicalisotretinoin(tmb001) pages 1-3)

Epidemiology (recently cited quantitative estimates)

A 2024 molecular diagnostic paper cited global frequency estimates: - ARCI prevalence: ~1:100,000–300,000 worldwide - X‑linked ichthyosis incidence: ~1:2000–1:6000 male newborns (fioretti2024comprehensivemolecularanalysis pages 1-2)

A 2023 review excerpt (from Nature Reviews Disease Primers) includes country-level prevalence figures presented in mixed formats; for example, it lists the United States as 200,000 patients (61 per 100,000). (gutierrezcerrajero2023ichthyosis pages 11-13)

Evidence caveat: The extracted 2023 primer chunks available in this tool run are not the full article and include tabulated prevalence figures without full definitional context; therefore, these values should be treated as secondary/compiled epidemiology rather than primary incidence studies. (gutierrezcerrajero2023ichthyosis pages 11-13)

10. Diagnostics

10.1 Clinical evaluation and pathology

Clinical evaluation plus family history guides initial classification, but phenotypic overlap and evolution can make subtyping difficult. The 2024 NGS study emphasizes that definitive classification requires DNA analysis. (fioretti2024comprehensivemolecularanalysis pages 2-3)

Review-level sources note that confirmation may include skin biopsy histology and electron microscopy in selected settings. (panda2025moleculargeneticsand pages 1-2)

10.2 Genetic testing (current real-world implementation)

Multi-gene NGS panels / WES/WGS: - A 2024 Italian series used targeted filtering across 54 ichthyosis/erythrokeratoderma genes in a high‑coverage NGS workflow and achieved molecular diagnosis in all 17/17 patients. (fioretti2024comprehensivemolecularanalysis pages 2-3) - The authors conclude comprehensive molecular testing can function as a first-tier diagnostic classifier for nonsyndromic ichthyosis. (fioretti2024comprehensivemolecularanalysis pages 1-2)

Direct quote (diagnostic rationale): “only the identification of the genetic defect allows the correct classification.” (fioretti2024comprehensivemolecularanalysis pages 1-2)

10.3 Differential diagnosis

Not systematically extractable from this evidence corpus; however, the diagnostic cohorts emphasize overlap across ichthyosis subtypes and the need for genetic confirmation. (fioretti2024comprehensivemolecularanalysis pages 2-3)

11. Outcome / prognosis

Severity and complications vary strongly by subtype and genotype.

Infection/sepsis outcomes (2024 congenital ichthyosis cohort): - 6 lethal infant sepsis cases (4 HI, 1 LI, 1 EI) - 10 treatable childhood sepsis cases (HI 3/8; IV 7/15) (ho2024alteredskinmicrobiome pages 2-4)

Evidence limitation: Survival/life expectancy estimates for specific inherited ichthyosis subtypes were not comprehensively retrieved (outside this cohort’s sepsis outcomes).

12. Treatment

12.1 Standard-of-care (symptomatic) therapy (general)

Symptom-directed care typically includes emollients/humectants/keratolytics and, in more severe disease, systemic retinoids; however, this report emphasizes recent targeted therapeutics and trial evidence because detailed guideline text was not available in the retrieved corpus. (panda2025moleculargeneticsand pages 2-3)

12.2 Recent developments (2023–2024): topical retinoid formulation (TMB‑001)

Topical isotretinoin (TMB‑001), Phase 2b CONTROL study (published May 2023): - Population: participants ≥9 years with confirmed XLRI or ARCI‑lamellar ichthyosis; n=33 randomized 1:1:1. (marathe2023topicalisotretinoin(tmb001) pages 1-3) - Efficacy responders reported in excerpt: VIIS‑50 achieved by 64% / 40% / 33% (TMB‑001 0.05% / 0.1% / vehicle) and IGA success by 55% / 40% / 8%, with mean baseline BSA affected 74%. (marathe2023topicalisotretinoin(tmb001) pages 3-4) - Safety: “Topical isotretinoin (tmb-001) treatment for 12 weeks did not result in clinically relevant laboratory abnormalities…” (Marathe 2023, Dermatology and Therapy, May 2023; https://doi.org/10.1007/s13555-023-00923-1). (marathe2023topicalisotretinoin(tmb001) pages 1-3)

Application/implementation: The study highlights a potential path to retinoid efficacy with reduced systemic laboratory toxicity compared with oral retinoids, which are known to cause clinically significant lab changes. (marathe2023topicalisotretinoin(tmb001) pages 1-3)

MAXO suggestions: topical retinoid therapy; topical keratolytic therapy (ontology IDs not retrieved in corpus).

12.3 Recent developments: topical gene therapy for TGM1-deficient ARCI (KB105)

KB105 (HSV‑1 vector expressing human TGM1; topical gel): - Phase I/II registry (NCT04047732; first posted 2019): intra‑patient comparison; up to 6 adults with genetically confirmed TGM1-deficient ARCI (null mutation) and lamellar ichthyosis; includes immunofluorescence measurement of TG1 in treated skin. (https://clinicaltrials.gov/study/NCT04047732) (NCT04047732 chunk 1) - Phase 2 registry (NCT05735158; posted 2023): intrasubject randomized, placebo-controlled, triple-masked study; enrollment 15; includes participants ≥6 months with genetically confirmed TGM1-deficient ARCI and lamellar ichthyosis; weekly application; primary endpoint composite IGA responder at Week 9. (https://clinicaltrials.gov/study/NCT05735158) (NCT05735158 chunk 1)

Expert/authoritative interpretation: These trials operationalize a pathogenesis‑based approach (gene replacement in skin) enabled by localized topical delivery, aligning with review-level framing that gene therapy is emerging for ichthyosis. (panda2025moleculargeneticsand pages 1-2)

MAXO suggestions: gene therapy; topical gene delivery (IDs not retrieved in corpus).

12.4 Biologics / immune-phenotype–guided therapy

Secukinumab (anti‑IL‑17A) in ichthyoses, Phase 2 trial: - NCT03041038: randomized, crossover, quadruple‑masked Phase 2; n=20; included ARCI (LI/CIE), epidermolytic ichthyosis, and Netherton syndrome; primary efficacy outcome reduction at Week 16 in Ichthyosis Area Severity Index (IASI). (NCT03041038 chunk 1)

Dupilumab repurposing trial for pruritic genetic inflammatory skin disorders (includes genetic skin disorders; ichthyosis may be included depending on phenotype): - NCT05649098: open-label pilot; n=30; primary goal is improvement in itch, targeting ≥50% of patients achieving ≥2‑point Worst Itch NRS reduction. (NCT05649098 chunk 1)

Mechanism–application link: The observed Th17/JAK/STAT activation and infection susceptibility in congenital ichthyosis supports the clinical rationale for immunomodulatory trials in selected immune-phenotypes. (ho2024alteredskinmicrobiome pages 1-2, NCT03041038 chunk 1)

13. Prevention

Primary prevention of inherited ichthyosis is limited (genetic disorders), but secondary prevention is feasible via early genetic diagnosis and counseling; diagnostic studies emphasize that NGS enables precise diagnosis and genetic counseling. (fioretti2024comprehensivemolecularanalysis pages 1-2, fioretti2024comprehensivemolecularanalysis pages 2-3)

14. Other species / natural disease

No OMIA/veterinary natural disease evidence was retrieved in this tool run; cannot be asserted.

15. Model organisms

Evidence in this corpus is limited; one review reports an ichthyosis-like phenotype in SMS2 knockout mice, supporting sphingomyelin/lipid pathway contributions to epidermal homeostasis. (panda2025moleculargeneticsand pages 2-3)

Recent quantitative findings summary (for knowledge base ingestion)

The table below consolidates key 2023–2024 quantitative findings across genetics, cohorts, mechanistic studies, and therapeutic trials.

Study / dataset Year Population / design Key quantitative findings URL Citations
Diociaiuti et al., Italian ARCI cohort 2024 Cross-sectional single-center cohort of 74 genetically diagnosed ARCI patients Subtypes: lamellar ichthyosis 50/74 (67.5%), CIE 18/74 (24.3%), harlequin ichthyosis 2/74 (2.7%), other ARCI 4/74 (5.4%). Mutated genes: TGM1 18/74 (24.3%), mean severity score 40.3 ± 14.1; ALOX12B 18/74 (24.3%), 23.2 ± 11.3; CYP4F22 12/74 (16.2%), 17.9 ± 5.1; ABCA12 9/74 (12.2%; higher severity than most other genes); ALOXE3 7/74 (9.5%); NIPAL4 7/74 (9.5%); CERS3, PNPLA1, SDR9C7 1/74 each (1.4%). 83 distinct sequence variants, including 25 previously undescribed; 2 microduplications in TGM1 and 2 microdeletions affecting CYP4F22/NIPAL4. Frequent features: hypohidrosis 54/74 (73.0%), heat intolerance 46/74 (62.2%), ear deformities 22/74 (29.7%), alopecia 16/74 (21.6%). https://doi.org/10.1159/000536366 (diociaiuti2024crosssectionalstudyon pages 4-5, diociaiuti2024crosssectionalstudyon media 464df4f0)
Fioretti et al., NGS first-tier molecular testing 2024 17 unrelated Italian patients with nonsyndromic ichthyosis; massively parallel sequencing of >50 ichthyosis-related genes; unaffected comparison set n=300 Molecular cause identified in 17/17 (100%). Diagnoses: 8/17 ARCI (ALOX12B, NIPAL4, TGM1), 3/17 with biallelic FLG loss-of-function, 6/11 males with X-linked ichthyosis. 24 disease-causing alleles detected, including 8 novel variants; included a synonymous TGM1 variant causing a splicing defect. Study supports multigene NGS as an effective first-tier diagnostic/classification test. https://doi.org/10.3390/biomedicines12051112 (fioretti2024comprehensivemolecularanalysis pages 1-2, fioretti2024comprehensivemolecularanalysis pages 2-3)
Marathe et al., TMB-001 CONTROL Phase 2b 2023 Randomized, double-blind, vehicle-controlled phase 2b trial; participants ≥9 years with genetically confirmed XLRI or ARCI-lamellar ichthyosis 33 enrolled: TMB-001 0.05% n=11, TMB-001 0.1% n=10, vehicle n=12; subtype split 52% ARCI-LI / 48% XLRI. Key efficacy: VIIS-50 achieved by 64% / 40% / 33% (0.05% / 0.1% / vehicle); IGA success by 55% / 40% / 8%. Mean baseline BSA affected 74%. Safety: 3/33 (9%) withdrew due to treatment-emergent AEs; no serious AEs or deaths; laboratory abnormalities were isolated/asymptomatic and authors reported no clinically significant laboratory changes through 12 weeks. https://doi.org/10.1007/s13555-023-00923-1 (marathe2023topicalisotretinoin(tmb001) pages 3-4, marathe2023topicalisotretinoin(tmb001) pages 1-3, NCT04154293 chunk 2)
Ho et al., microbiome / inflammation / JAK-STAT study 2024 Southeast Asian case-control study with congenital ichthyosis patients and healthy controls; WES plus skin metagenomics and immune profiling Cohort: 36 CI patients + 15 controls (total 51); mean age 10.2 years, median follow-up 4.3 years. Subtypes: IV 15, HI 8, LI 3, EI 4, TTD 3, ARC 1, SLS 2. Clinical burden: hyperkeratosis 100%, itch 97.2%, microbial infection 94.4%, erythroderma 72.2%, mental health difficulty 53% (19/36). Sepsis: 6 lethal infant cases (4 HI, 1 LI, 1 EI) plus 10 treatable childhood sepsis cases (HI 3/8; IV 7/15). Genetics: 20 novel + 31 recurrent/pathogenic variants. Mechanistic findings: reduced commensals, increased pathogenic colonization, elevated Th17 and JAK/STAT signaling; all CI clusters showed elevated neutrophils, eosinophils elevated in one cluster, and STAT3 pY705 increased in P2/P3/P4. https://doi.org/10.1186/s40246-024-00603-x (ho2024alteredskinmicrobiome pages 10-13, ho2024alteredskinmicrobiome pages 1-2, ho2024alteredskinmicrobiome pages 2-4)
KB105 topical gene therapy, NCT04047732 2019 registry record Phase I/II intra-patient topical gene therapy trial for TGM1-deficient ARCI Planned enrollment up to 6 adults. KB105 is a replication-incompetent, non-integrating HSV-1 vector expressing human TGM1 in topical gel. Key inclusion: genetically confirmed TGM1-deficient ARCI with a null TGM1 mutation, clinical diagnosis of lamellar ichthyosis, age ≥18 years, target-area IGA 3–4. Primary focus: safety/tolerability and IGA improvement over ~12 weeks. https://clinicaltrials.gov/study/NCT04047732 (NCT04047732 chunk 1)
KB105 topical gene therapy, NCT05735158 2023 registry record Phase 2, intrasubject randomized, placebo-controlled, triple-masked study of topical KB105 Planned enrollment 15 children/adults. Weekly topical KB105 vs matched placebo on paired target areas, with optional open-label area. Key inclusion: age ≥6 months, genetically confirmed TGM1-deficient ARCI, clinical diagnosis of lamellar ichthyosis, paired target areas with same scaling severity and severity ≥3. Primary endpoint: composite IGA responder at Week 9. https://clinicaltrials.gov/study/NCT05735158 (NCT05735158 chunk 1)

Table: This table compiles recent quantitative findings across genetics, clinical cohorts, immune/microbiome studies, and therapeutic trials in inherited ichthyosis. It highlights sample sizes, subtype distributions, gene frequencies, severity metrics, and design features most useful for a disease knowledge base.

Evidence gaps (what is not currently supported by the retrieved corpus)

  • Verified MONDO/Orphanet/OMIM/MeSH/ICD mappings for the umbrella term “inherited ichthyosis”.
  • Comprehensive modifier gene / epigenetic associations.
  • Systematic environmental risk/protective factors.
  • Detailed guideline algorithms for treatment stratified by subtype (a 2024 guideline update appears in search results but was unobtainable in this run).

References

  1. (xiang2025theclinicalspectrum pages 1-2): Ruiyu Xiang, Xin Huang, Yihe Liu, Shuya Sun, Di Hua, Ran Mo, Yong Yang, and Zhiming Chen. The clinical spectrum of rare inherited ichthyosis in china: a review of thirty-five cases. Acta Dermato-Venereologica, Jul 2025. URL: https://doi.org/10.2340/actadv.v105.41100, doi:10.2340/actadv.v105.41100. This article has 1 citations and is from a domain leading peer-reviewed journal.

  2. (fioretti2024comprehensivemolecularanalysis pages 1-2): Tiziana Fioretti, Fabrizio Martora, Ilaria De Maggio, Adelaide Ambrosio, Carmelo Piscopo, Sabrina Vallone, Felice Amato, Diego Passaro, Fabio Acquaviva, Francesca Gaudiello, Daniela Di Girolamo, Valeria Maiolo, Federica Zarrilli, Speranza Esposito, Giuseppina Vitiello, Luigi Auricchio, Elena Sammarco, Daniele De Brasi, Roberta Petillo, Antonella Gambale, Fabio Cattaneo, Rosario Ammendola, Paola Nappa, and Gabriella Esposito. Comprehensive molecular analysis of disease-related genes as first-tier test for early diagnosis, classification, and management of patients affected by nonsyndromic ichthyosis. Biomedicines, 12:1112, May 2024. URL: https://doi.org/10.3390/biomedicines12051112, doi:10.3390/biomedicines12051112. This article has 2 citations.

  3. (panda2025moleculargeneticsand pages 2-3): Suman Panda. Molecular genetics and pathogenesis of ichthyosis. Annals of Medical and Surgical Dermatology, Jan 2025. URL: https://doi.org/10.61577/amsd.2023.100004, doi:10.61577/amsd.2023.100004. This article has 1 citations.

  4. (marathe2023topicalisotretinoin(tmb001) pages 1-3): Kalyani Marathe, Joyce M. C. Teng, Scott Guenthner, Christopher G. Bunick, Steven Kempers, Kimmie Eads, Leslie Castelo-Soccio, Alan M. Mendelsohn, Jessica Raiz, and Dédée F. Murrell. Topical isotretinoin (tmb-001) treatment for 12 weeks did not result in clinically relevant laboratory abnormalities in participants with congenital ichthyosis in the phase 2b control study. Dermatology and Therapy, 13:1255-1264, May 2023. URL: https://doi.org/10.1007/s13555-023-00923-1, doi:10.1007/s13555-023-00923-1. This article has 6 citations.

  5. (ho2024alteredskinmicrobiome pages 2-4): Minh Ho, Huynh-Nga Nguyen, Minh Van Hoang, Tien Thuy Thi Bui, Bao-Quoc Vu, Truc Huong Thi Dinh, Hoa Thi My Vo, Diana C. Blaydon, Sherif A. Eldirany, Christopher G. Bunick, and Chi-Bao Bui. Altered skin microbiome, inflammation, and jak/stat signaling in southeast asian ichthyosis patients. Human Genomics, Apr 2024. URL: https://doi.org/10.1186/s40246-024-00603-x, doi:10.1186/s40246-024-00603-x. This article has 14 citations and is from a peer-reviewed journal.

  6. (fioretti2024comprehensivemolecularanalysis pages 2-3): Tiziana Fioretti, Fabrizio Martora, Ilaria De Maggio, Adelaide Ambrosio, Carmelo Piscopo, Sabrina Vallone, Felice Amato, Diego Passaro, Fabio Acquaviva, Francesca Gaudiello, Daniela Di Girolamo, Valeria Maiolo, Federica Zarrilli, Speranza Esposito, Giuseppina Vitiello, Luigi Auricchio, Elena Sammarco, Daniele De Brasi, Roberta Petillo, Antonella Gambale, Fabio Cattaneo, Rosario Ammendola, Paola Nappa, and Gabriella Esposito. Comprehensive molecular analysis of disease-related genes as first-tier test for early diagnosis, classification, and management of patients affected by nonsyndromic ichthyosis. Biomedicines, 12:1112, May 2024. URL: https://doi.org/10.3390/biomedicines12051112, doi:10.3390/biomedicines12051112. This article has 2 citations.

  7. (diociaiuti2024crosssectionalstudyon pages 4-5): Andrea Diociaiuti, Marialuisa Corbeddu, Sabrina Rossi, Elisa Pisaneschi, Claudia Cesario, Angelo Giuseppe Condorelli, Tonia Samela, Simona Giancristoforo, Adriano Angioni, Giovanna Zambruno, Antonio Novelli, Rita Alaggio, Damiano Abeni, and May El Hachem. Cross-sectional study on autosomal recessive congenital ichthyoses: association of genotype with disease severity, phenotypic, and ultrastructural features in 74 italian patients. Dermatology (Basel, Switzerland), 240:397-413, Apr 2024. URL: https://doi.org/10.1159/000536366, doi:10.1159/000536366. This article has 10 citations.

  8. (diociaiuti2024crosssectionalstudyon media 464df4f0): Andrea Diociaiuti, Marialuisa Corbeddu, Sabrina Rossi, Elisa Pisaneschi, Claudia Cesario, Angelo Giuseppe Condorelli, Tonia Samela, Simona Giancristoforo, Adriano Angioni, Giovanna Zambruno, Antonio Novelli, Rita Alaggio, Damiano Abeni, and May El Hachem. Cross-sectional study on autosomal recessive congenital ichthyoses: association of genotype with disease severity, phenotypic, and ultrastructural features in 74 italian patients. Dermatology (Basel, Switzerland), 240:397-413, Apr 2024. URL: https://doi.org/10.1159/000536366, doi:10.1159/000536366. This article has 10 citations.

  9. (panda2025moleculargeneticsand pages 3-4): Suman Panda. Molecular genetics and pathogenesis of ichthyosis. Annals of Medical and Surgical Dermatology, Jan 2025. URL: https://doi.org/10.61577/amsd.2023.100004, doi:10.61577/amsd.2023.100004. This article has 1 citations.

  10. (NCT05610306 chunk 1): Quality of Life in Middle-aged and Older Patients With Congenital Ichthyosis. Maastricht University Medical Center. 2022. ClinicalTrials.gov Identifier: NCT05610306

  11. (panda2025moleculargeneticsand pages 1-2): Suman Panda. Molecular genetics and pathogenesis of ichthyosis. Annals of Medical and Surgical Dermatology, Jan 2025. URL: https://doi.org/10.61577/amsd.2023.100004, doi:10.61577/amsd.2023.100004. This article has 1 citations.

  12. (ho2024alteredskinmicrobiome pages 1-2): Minh Ho, Huynh-Nga Nguyen, Minh Van Hoang, Tien Thuy Thi Bui, Bao-Quoc Vu, Truc Huong Thi Dinh, Hoa Thi My Vo, Diana C. Blaydon, Sherif A. Eldirany, Christopher G. Bunick, and Chi-Bao Bui. Altered skin microbiome, inflammation, and jak/stat signaling in southeast asian ichthyosis patients. Human Genomics, Apr 2024. URL: https://doi.org/10.1186/s40246-024-00603-x, doi:10.1186/s40246-024-00603-x. This article has 14 citations and is from a peer-reviewed journal.

  13. (ho2024alteredskinmicrobiome pages 10-13): Minh Ho, Huynh-Nga Nguyen, Minh Van Hoang, Tien Thuy Thi Bui, Bao-Quoc Vu, Truc Huong Thi Dinh, Hoa Thi My Vo, Diana C. Blaydon, Sherif A. Eldirany, Christopher G. Bunick, and Chi-Bao Bui. Altered skin microbiome, inflammation, and jak/stat signaling in southeast asian ichthyosis patients. Human Genomics, Apr 2024. URL: https://doi.org/10.1186/s40246-024-00603-x, doi:10.1186/s40246-024-00603-x. This article has 14 citations and is from a peer-reviewed journal.

  14. (gutierrezcerrajero2023ichthyosis pages 11-13): Carlos Gutiérrez-Cerrajero, Eli Sprecher, Amy S. Paller, Masashi Akiyama, Juliette Mazereeuw-Hautier, Angela Hernández-Martín, and Rogelio González-Sarmiento. Ichthyosis. Nature Reviews Disease Primers, 9:1-23, Jan 2023. URL: https://doi.org/10.1038/s41572-022-00412-3, doi:10.1038/s41572-022-00412-3. This article has 93 citations.

  15. (marathe2023topicalisotretinoin(tmb001) pages 3-4): Kalyani Marathe, Joyce M. C. Teng, Scott Guenthner, Christopher G. Bunick, Steven Kempers, Kimmie Eads, Leslie Castelo-Soccio, Alan M. Mendelsohn, Jessica Raiz, and Dédée F. Murrell. Topical isotretinoin (tmb-001) treatment for 12 weeks did not result in clinically relevant laboratory abnormalities in participants with congenital ichthyosis in the phase 2b control study. Dermatology and Therapy, 13:1255-1264, May 2023. URL: https://doi.org/10.1007/s13555-023-00923-1, doi:10.1007/s13555-023-00923-1. This article has 6 citations.

  16. (NCT04047732 chunk 1): Topical KB105 Gene Therapy for the Treatment of TGM1-deficient Autosomal Recessive Congenital Ichthyosis (ARCI). Krystal Biotech, Inc.. 2019. ClinicalTrials.gov Identifier: NCT04047732

  17. (NCT05735158 chunk 1): Topical KB105 for the Treatment of TGM1-deficient Autosomal Recessive Congenital Ichthyosis (ARCI). Krystal Biotech, Inc.. 2023. ClinicalTrials.gov Identifier: NCT05735158

  18. (NCT03041038 chunk 1): Amy Paller. The Efficacy and Safety of Secukinumab in Patients With Ichthyoses. Northwestern University. 2016. ClinicalTrials.gov Identifier: NCT03041038

  19. (NCT05649098 chunk 1): Amy Paller. Repurposing Dupilumab for Management of Pruritic Genetic Inflammatory Skin Disorders. Northwestern University. 2023. ClinicalTrials.gov Identifier: NCT05649098

  20. (NCT04154293 chunk 2): A Vehicle Controlled Study to Evaluate Safety and Efficacy of Topical TMB-001 for Treatment of Congenital Ichthyosis. Timber Pharmaceuticals Inc.. 2019. ClinicalTrials.gov Identifier: NCT04154293