KRT85-related ectodermal dysplasia 4, hair/nail type (ECTD4) is a rare autosomal recessive disorder caused by biallelic loss-of-function mutations in KRT85, which encodes keratin 85, a type II hair-specific keratin expressed in the hair cortex and nail matrix. Affected individuals present with hypotrichosis, alopecia, and nail dystrophy from early childhood. Unlike hypohidrotic forms of ectodermal dysplasia, sweat gland function and dentition are normal, restricting the phenotype to hair and nail appendages. The disorder exemplifies how disruption of a single hair-specific keratin intermediate filament protein can selectively compromise hair shaft structural integrity without affecting other ectodermal derivatives.
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name: KRT85-Related Pure Hair-Nail Ectodermal Dysplasia
creation_date: "2026-04-24T00:00:00Z"
updated_date: "2026-04-24T00:00:00Z"
description: >-
KRT85-related ectodermal dysplasia 4, hair/nail type (ECTD4) is a rare autosomal
recessive disorder caused by biallelic loss-of-function mutations in KRT85, which
encodes keratin 85, a type II hair-specific keratin expressed in the hair cortex
and nail matrix. Affected individuals present with hypotrichosis, alopecia,
and nail dystrophy from early childhood. Unlike hypohidrotic forms of ectodermal
dysplasia, sweat gland function and dentition are normal, restricting the phenotype
to hair and nail appendages. The disorder exemplifies how disruption of a single
hair-specific keratin intermediate filament protein can selectively compromise
hair shaft structural integrity without affecting other ectodermal derivatives.
category: Genetic
parents:
- Ectodermal Dysplasia
disease_term:
preferred_term: ectodermal dysplasia 4, hair/nail type
term:
id: MONDO:0011177
label: ectodermal dysplasia 4, hair/nail type
genetic:
- name: KRT85 Loss-of-Function Mutations
gene_term:
preferred_term: KRT85
term:
id: hgnc:6462
label: KRT85
inheritance:
- name: Autosomal recessive
evidence:
- reference: PMID:16525032
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
large Pakistani consanguineous kindred with multiple affected individuals
has been ascertained from a remote region in Pakistan
explanation: >-
The original KRT85 mutation was identified in a consanguineous family
consistent with autosomal recessive inheritance.
variants:
- name: R78H (c.233G>A) missense
description: >-
Homozygous missense mutation in the head domain of KRT85, converting
a conserved arginine residue at position 78 to histidine. This was
the first KRT85 mutation identified and is associated with a severe
phenotype including complete alopecia and severe nail dystrophy.
evidence:
- reference: PMID:16525032
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
DNA sequence analysis revealed a homozygous missense mutation in the
hair matrix and cuticle keratin KRTHB5, leading to histidine
substitution of a conserved arginine residue (R78H) located in the
head domain
explanation: >-
First identification of the R78H mutation in KRT85 as the cause of
pure hair-nail ectodermal dysplasia.
- reference: PMID:33605551
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
a missense mutation (233A>G) that replaces Arg78 with His (R78H) in
the head domain of K85 did not interfere with the filament formation
explanation: >-
In vitro functional analysis showed that R78H does not prevent K85-K35
filament assembly in SW-13 cells, suggesting a more subtle structural
defect rather than complete loss of filament formation.
- name: delCT (c.1448_1449del) frameshift
description: >-
Homozygous two-nucleotide deletion in the tail domain of KRT85 causing
a frameshift and premature termination codon. This mutation abolishes
K85-K35 filament formation entirely.
evidence:
- reference: PMID:33605551
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
a two-nucleotide (C1448 T1449) deletion (delCT) in the protein tail
domain of K85 interfered with the K85-K35 filament formation and gave
only aggregates
explanation: >-
The delCT frameshift mutation completely abolishes filament assembly,
producing only protein aggregates when co-expressed with K35.
- name: Compound heterozygous variants (c.502_525del + c.886A>G)
description: >-
Compound heterozygosity for an in-frame deletion (c.502_525del,
p.del168_175) and a missense variant (c.886A>G, p.Lys296Glu) identified
in two sisters from a non-consanguineous French family. Both variants
were absent from gnomAD. This was the first report of compound
heterozygous KRT85 mutations and demonstrates that ECTD4 can occur
in non-consanguineous families.
evidence:
- reference: PMID:16525032
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
This report provides the first direct evidence relating to the
molecular pathogenesis of pure hair-nail ectodermal dysplasias
explanation: >-
Establishes KRT85 as a causative gene for pure hair-nail ectodermal
dysplasia through linkage analysis and mutation identification.
- reference: PMID:21176769
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
ectodermal dysplasia (ED; K85)
explanation: >-
Review confirming K85 (KRT85) as the gene responsible for ectodermal
dysplasia of hair and nail type within the broader keratin genodermatosis
classification.
pathophysiology:
- name: Hair Keratin Intermediate Filament Disruption
description: >-
KRT85 is a type II keratin that heterodimerizes with type I keratins
(particularly KRT35) to form intermediate filaments in the hair cortex.
K85 and K35 are the first hair keratins expressed in cortical cells at
the early stage of differentiation and are critical for proto-macrofibril
formation. Loss of KRT85 disrupts the structural integrity of keratin
intermediate filaments in the hair shaft cortex, leading to mechanically
fragile, poorly formed hair shafts.
cell_types:
- preferred_term: Hair follicle cell
term:
id: CL:0002559
label: hair follicle cell
biological_processes:
- preferred_term: Keratinization
term:
id: GO:0031424
label: keratinization
modifier: DECREASED
- preferred_term: Intermediate filament organization
term:
id: GO:0045109
label: intermediate filament organization
- preferred_term: Hair follicle development
term:
id: GO:0001942
label: hair follicle development
evidence:
- reference: PMID:33605551
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
K85 and K35 are the first hair keratins expressed in cortical cells
at the early stage of the differentiation. Two types of mutations in
the gene encoding K85 are associated with ectodermal dysplasia of
hair and nail type
explanation: >-
Demonstrates that K85 and K35 are the earliest hair keratins expressed
in cortical cells, and that K85 mutations cause ectodermal dysplasia.
- reference: PMID:33605551
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
The K85-K35 pair formed short filaments in the cytoplasm, which
gradually elongated and became thicker and entangled around the
nucleus, indicating that K85-K35 promotes lateral association of
short intermediate filaments (IFs) into bundles but cannot form IF
networks in the cytoplasm
explanation: >-
Characterization of K85-K35 intermediate filament assembly shows unique
bundling behavior distinct from cytokeratin networks, essential for
proto-macrofibril formation in hair cortex.
- reference: PMID:16525032
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The disease locus was mapped to a 16.6 centimorgan region on chromosome
12q12-q14.1 (Zmax = 8.2), which harbours six type II hair keratin genes
explanation: >-
Linkage mapping localized the disease to the type II hair keratin
gene cluster on chromosome 12q, confirming hair keratin disruption
as the molecular basis.
downstream:
- target: Nail Matrix Keratin Deficiency
- name: Nail Matrix Keratin Deficiency
description: >-
KRT85 is also expressed in the nail matrix, where it contributes to
nail plate formation. Loss of KRT85 leads to structurally abnormal
nail plates manifesting as nail dystrophy, with brittle, ridged, or
malformed nails.
cell_types:
- preferred_term: Nail matrix keratinocyte
term:
id: CL:4052064
label: nail matrix keratinocyte
biological_processes:
- preferred_term: Keratinization
term:
id: GO:0031424
label: keratinization
modifier: DECREASED
evidence:
- reference: PMID:21176769
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Molecular defects in cutaneous keratin genes encoding for keratin
intermediate filaments (KIFs) causes keratinocytes and tissue-specific
fragility, accounting for a large number of genetic disorders in human
skin and its appendages
explanation: >-
Review establishing that keratin intermediate filament defects cause
tissue-specific fragility in skin appendages including nails.
phenotypes:
- category: Dermatologic
name: Hypotrichosis
description: >-
Sparse scalp hair (hypotrichosis) present from birth, reflecting
disrupted hair shaft formation due to defective keratin intermediate filament
assembly in the hair cortex. Sparse eyebrows, eyelashes, and body hair
have also been observed in some families (Shimomura 2010, Amico 2019).
phenotype_term:
preferred_term: Sparse scalp hair
term:
id: HP:0002209
label: Sparse scalp hair
evidence:
- reference: PMID:16525032
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
four different types of ectodermal dysplasia involving only hair and
nails have been described
explanation: >-
Establishes that KRT85-related ectodermal dysplasia involves hair
(hypotrichosis) as a defining feature of this pure hair-nail subtype.
- category: Dermatologic
name: Nail Dystrophy
description: >-
Abnormal nail plate formation with ridging, brittleness, or malformation
affecting fingernails and toenails from birth, resulting from defective
keratinization in the nail matrix.
phenotype_term:
preferred_term: Nail dystrophy
term:
id: HP:0008404
label: Nail dystrophy
evidence:
- reference: PMID:16525032
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
four different types of ectodermal dysplasia involving only hair and
nails have been described
explanation: >-
Establishes nail involvement as a defining feature of KRT85-related
pure hair-nail ectodermal dysplasia.
- category: Dermatologic
name: Abnormal Hair Shaft Morphology
description: >-
Structural abnormalities of the hair shaft visible on light or electron
microscopy, reflecting disrupted keratin intermediate filament organization
within the cortex.
phenotype_term:
preferred_term: Abnormal hair shaft morphology
term:
id: HP:0003328
label: Abnormal hairshaft morphology
evidence:
- reference: PMID:33605551
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
a two-nucleotide (C1448 T1449) deletion (delCT) in the protein tail
domain of K85 interfered with the K85-K35 filament formation and gave
only aggregates
explanation: >-
Demonstrates that KRT85 mutations can completely disrupt filament
formation, producing only aggregates rather than normal intermediate
filaments, which would manifest as abnormal hair shaft morphology.
- category: Dermatologic
name: Alopecia
description: >-
Progressive or complete loss of scalp hair. Complete alopecia has been
reported with certain KRT85 mutations, particularly the R78H missense
mutation in the head domain. Some individuals show partial improvement
after puberty.
phenotype_term:
preferred_term: Alopecia
term:
id: HP:0001596
label: Alopecia
notes: >-
Complete alopecia reported for R78H homozygotes (PMID:16525032 full text,
PMID:19865094 letter); no accessible abstract text for snippet-based
evidence.
treatments:
- name: Symptomatic Management
description: >-
No specific treatment exists for the underlying keratin defect.
Management is supportive and includes gentle hair care to minimize
breakage, nail care, and cosmetic interventions such as wigs.
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
- name: Genetic Counseling
description: >-
Genetic counseling for autosomal recessive inheritance pattern,
carrier testing for family members, and prenatal diagnosis when
the familial mutations are known.
treatment_term:
preferred_term: genetic counseling
term:
id: MAXO:0000079
label: genetic counseling
evidence:
- reference: PMID:21176769
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The identification of specific pathogenic mutations in keratin disorders
formed the basis of our understanding that led to re-classification,
improved diagnosis with prognostic implications, prenatal testing and
genetic counseling in severe keratin genodermatoses
explanation: >-
Review confirming that identification of keratin gene mutations enables
genetic counseling and prenatal testing for keratin genodermatoses.
datasets:
KRT85-related pure hair–nail ectodermal dysplasia (PHNED; also written PHNEC) is a congenital genetic disorder characterized primarily by hypotrichosis/atrichia (ranging from sparse fragile hair to complete alopecia) and nail dystrophy, with other ectodermal structures (e.g., teeth and sweating) typically spared (“pure” hair–nail involvement). (shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3)
Evidence-supported identifiers and names from the retrieved literature are summarized in the table artifact below.
| Recommended disease name | Synonyms / alternative names | OMIM disease ID | OMIM gene ID (KRT85) | Historical gene names | Chromosomal locus / region | MONDO ID from evidence | Evidence citation IDs | Key source URLs |
|---|---|---|---|---|---|---|---|---|
| KRT85-related pure hair and nail ectodermal dysplasia | Pure hair and nail ectodermal dysplasia (PHNED); Pure hair and nail ectodermal dysplasia / PHNEC; Ectodermal dysplasia of hair and nail type; Ectodermal dysplasia 4, hair/nail type (ECTD4) | 602032 | 602767 | KRT85; KRTHB5; hHb5 | KRT85 resides in the type II keratin cluster at 12q13 / 12q13.13; disease locus mapped in reports to 12q12-q14.1 and 12p11.1-q21.1 / 12q13 region | Not specifically identified for this disease in retrieved evidence; only broader Open Targets association to ectodermal dysplasia syndrome MONDO_0019287 was returned, so disease-specific MONDO should be treated as unavailable from current evidence | (shimomura2010mutationsinthe pages 1-2, naeem2006amutationin pages 1-2, amico2019compoundheterozygosityfor pages 1-3, naeem2006amutationin pages 3-4, lin2012lossoffunctionmutationsin pages 1-2) | https://doi.org/10.1038/jid.2009.341 ; https://doi.org/10.1136/jmg.2005.033381 ; https://doi.org/10.1111/jdv.15777 ; https://doi.org/10.1016/j.ajhg.2012.08.029 |
Table: This table summarizes the core identifiers, synonyms, historical nomenclature, and locus information for KRT85-related pure hair and nail ectodermal dysplasia. It is useful as a normalization artifact for a disease knowledge base entry, with evidence-linked terminology and source URLs.
Notes on disease identifiers not recovered from tools: * Disease-specific MONDO, Orphanet, MeSH, and ICD-10/ICD-11 codes were not present in the retrieved full-text excerpts; only a broad Open Targets disease label (“ectodermal dysplasia syndrome”, MONDO_0019287) was returned and should not be treated as disease-specific for KRT85-PHNED. (artifact-00)
The KRT85-related entity is supported mainly by (i) human family-based linkage and candidate-gene sequencing studies and (ii) subsequent NGS-panel diagnosis reports. (naeem2006amutationin pages 1-2, shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3)
Primary cause: biallelic pathogenic variants in KRT85 (historical name KRTHB5/hHb5; OMIM gene MIM 602767) disrupt hard-keratin intermediate filament biology in hair and nail. (shimomura2010mutationsinthe pages 1-2, naeem2006amutationin pages 1-2)
Mode of inheritance: most documented KRT85 cases are autosomal recessive, often in consanguineous families. (naeem2006amutationin pages 1-2, shimomura2010mutationsinthe pages 1-2)
Genetic risk factors: consanguinity/familial carrier status increases risk of homozygosity for pathogenic alleles (as illustrated by large consanguineous Pakistani pedigrees). (naeem2006amutationin pages 1-2, shimomura2010mutationsinthe pages 1-2)
Environmental risk factors: no disease-specific environmental triggers have been established in the retrieved primary literature. One report noted worsening of alopecia after febrile episodes in affected siblings with compound heterozygous KRT85 variants; this observation does not establish causality but suggests symptoms can fluctuate with systemic stressors. (amico2019compoundheterozygosityfor pages 1-3)
No genetic or environmental protective factors were identified in the retrieved evidence.
No validated gene–environment interaction studies specific to KRT85-PHNED were identified in the retrieved evidence.
Across reported KRT85-PHNED families, phenotypes include: * Congenital hypotrichosis/atrichia: scalp, facial (including eyebrows/eyelashes), and body hair can be sparse to absent; some families show complete alopecia. (naeem2006amutationin pages 2-3, shimomura2010mutationsinthe pages 1-2) * Hair-shaft fragility and structural abnormalities: scanning electron microscopy (SEM) demonstrated inconsistent hair-shaft thickness (not periodic like monilethrix) in one family; clinically hair is thin/fragile and breaks easily. (shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3) * Nail dystrophy: irregularly shaped, fragile nails; can include micronychia, koilonychia, distal onycholysis; severe nail deformities reported in severe cases. (shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3) * Relative sparing of other ectodermal structures: normal teeth and normal sweating are repeatedly reported in KRT85-PHNED families. (shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3)
Pedigrees, clinical photos, and SEM hair images supporting these features are shown in Shimomura et al. 2010 (Figure 1), and the KRT85 variant evidence is shown in their Figure 2. (shimomura2010mutationsinthe media b5f82a0b, shimomura2010mutationsinthe media a9ef3a76)
No disease-specific quantitative QoL instruments (e.g., DLQI, SF-36) were identified in the retrieved primary literature; given visible alopecia and nail fragility, psychosocial and functional impacts are plausible but not evidenced quantitatively here.
KRT85 encodes a type II hair keratin expressed in hair matrix/precortex/cuticle cells; impaired availability of functional type II hair keratin to pair with type I partners is proposed to underlie the abnormal hair phenotype. (amico2019compoundheterozygosityfor pages 1-3)
Pathogenic/likely pathogenic variants reported in retrieved primary/clinical literature include: * c.233G>A (p.Arg78His), exon 1: homozygous in a large consanguineous Pakistani pedigree with complete alopecia and nail dystrophy; absent in 100 unrelated controls (200 chromosomes). (naeem2006amutationin pages 3-4) * c.1448_1449delCT (p.Pro483Argfs*18), exon 9: homozygous frameshift predicted to truncate the protein; reported in consanguineous Pakistani families and absent from 100 healthy Pakistani controls in one study. (shimomura2010mutationsinthe pages 1-2) * c.502_525del (p.del168_175) (in-frame deletion) and c.886A>G (p.Lys296Glu) (missense): compound heterozygosity in two sisters from a non-consanguineous French family; both reported absent from gnomAD. (amico2019compoundheterozygosityfor pages 1-3)
Variant classes: missense, frameshift, and in-frame deletion are represented among reported alleles. (shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3)
Population frequency statements: * c.233G>A was not detected in 100 unrelated controls in the original linkage/candidate gene report. (naeem2006amutationin pages 3-4) * The 2019 report states both compound heterozygous variants were absent from gnomAD. (amico2019compoundheterozygosityfor pages 1-3)
Somatic vs germline: all reported variants are germline and segregate with disease in families. (naeem2006amutationin pages 1-2, shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3)
No validated modifier genes, epigenetic signatures, or chromosomal abnormalities specific to KRT85-PHNED were identified in the retrieved evidence.
A coherent mechanism supported by available evidence is: 1. Biallelic KRT85 variants (frameshift or missense) alter K85 structure/function. (shimomura2010mutationsinthe pages 1-2) 2. K85 dysfunction is proposed to impair intermediate filament assembly/heterodimer formation in hard-keratinizing structures (hair shaft and nails), consistent with keratin biology and with a truncation predicted to alter the C-terminal tail (loss of cysteine residues) and thus disrupt keratin interactions. (shimomura2010mutationsinthe pages 1-2) 3. The result is abnormal hair-shaft formation and fragility and nail dystrophy, manifesting clinically as hypotrichosis/alopecia and dystrophic nails. (shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3)
Suggested GO Biological Process terms (examples): * keratinization (GO:0031424) * hair follicle development (GO:0001942) * hair cycle process (GO:0022405) * intermediate filament organization (GO:0045109)
Suggested GO Cellular Component terms: * intermediate filament (GO:0005882) * keratin filament (GO:0045095)
Suggested Cell Ontology (CL) terms (examples): * keratinocyte (CL:0000312) * hair follicle keratinocyte (more specific subtypes vary by ontology version)
No specific environmental, lifestyle, or infectious contributors were identified for KRT85-PHNED in the retrieved evidence. One family reported symptom worsening after febrile episodes. (amico2019compoundheterozygosityfor pages 1-3)
Primary structures affected are hair follicles (hair shaft production) and nail unit (nail matrix/plate). KRT85 is described as a hair keratin expressed in hair matrix/precortex/cuticle; clinical findings are limited to hair and nails without broader ectodermal involvement in the cases described. (amico2019compoundheterozygosityfor pages 1-3, shimomura2010mutationsinthe pages 1-2)
No formal staging systems or longitudinal natural history cohorts were identified.
Human reports support autosomal recessive inheritance for KRT85-PHNED. (naeem2006amutationin pages 1-2, shimomura2010mutationsinthe pages 1-2)
No prevalence or incidence estimates specific to KRT85-PHNED were available in the retrieved evidence. A contemporary ectodermal dysplasia classification review highlights that many EDs are ultra-rare with missing prevalence data and may be underdiagnosed, while providing prevalence estimates for hypohidrotic ED as context (not for KRT85-PHNED). (peschel2022molecularpathwaybasedclassification pages 1-2)
No carrier frequency estimates, founder effects, or population-based prevalence statistics for KRT85 pathogenic variants were identified in the retrieved evidence.
Diagnosis is suspected clinically based on the combination of congenital hypotrichosis/alopecia and nail dystrophy with normal teeth and sweating and no major additional ectodermal findings. (shimomura2010mutationsinthe pages 1-2, amico2019compoundheterozygosityfor pages 1-3)
Evidence-supported approaches include: * Linkage mapping + candidate gene Sanger sequencing in large pedigrees (historical approach). (naeem2006amutationin pages 1-2, shimomura2010mutationsinthe pages 1-2) * Targeted next-generation sequencing (NGS) panel testing: a “gene chip-based next-generation sequencing” panel of 22 hypotrichosis genes was used to identify compound heterozygous KRT85 variants in siblings, enabling rapid molecular confirmation and informing genetic counseling. (amico2019compoundheterozygosityfor pages 1-3)
Differential diagnosis (evidence-informed): other “pure” hair–nail ectodermal dysplasias due to HOXC13 or KRT74, and other congenital alopecia/hair-shaft disorders (e.g., monilethrix) are relevant considerations; within PHNED, genetic heterogeneity is emphasized. (amico2019compoundheterozygosityfor pages 1-3, lin2012lossoffunctionmutationsin pages 1-2)
No mortality signal or systemic organ involvement is described in the retrieved KRT85-focused families; affected individuals are described as otherwise healthy with normal intelligence and normal routine lab tests in at least one large pedigree. (naeem2006amutationin pages 2-3)
Quantitative prognosis metrics (survival, morbidity indices) are not available from the retrieved evidence.
No disease-modifying pharmacologic, gene, or cell therapies were identified in the retrieved evidence for KRT85-PHNED.
The retrieved primary literature and brief reports did not provide detailed management algorithms. The strongest evidence-based “intervention” discussed is genetic counseling enabled by molecular diagnosis. (amico2019compoundheterozygosityfor pages 1-3)
Suggested MAXO terms (as knowledge-base annotations; not asserted as evidence-based efficacy): * genetic counseling (MAXO:0000747) * molecular genetic testing (MAXO:0000059) * wig/hair prosthesis use (supportive) * nail care / protective measures (supportive)
No primary prevention exists because the disorder is monogenic. Secondary/tertiary prevention is primarily through: * Carrier testing and cascade testing in families once a pathogenic variant is identified (supported indirectly by segregation and counseling emphasis). (amico2019compoundheterozygosityfor pages 1-3)
No naturally occurring veterinary disease analogs for KRT85-PHNED were identified in the retrieved evidence.
Direct KRT85 disease models were not identified in the retrieved evidence. However, the broader PHNED genetic landscape includes HOXC13-related models (e.g., Hoxc13 mutant mice) used to study hair/nail biology; these inform shared pathway biology but are not KRT85-specific. (lin2012lossoffunctionmutationsin pages 1-2)
Because several key KRT85-PHNED papers were retrieved as full-text pages without clearly captured abstract fields, direct abstract quotations are limited. One available direct abstract quote relevant to “pure hair and nail ectodermal dysplasia” definition (not specific to KRT85 but defining PHNED) is: * “Pure hair and nail ectodermal dysplasia (PHNED) comprises a heterogeneous group of rare heritable disorders characterized by brittle hair, hypotrichosis, onychodystrophy and micronychia.” (Raykova et al., 2014; KRT74-related PHNED subtype) (lin2012lossoffunctionmutationsin pages 1-2)
An expert-panel ectodermal dysplasia classification update emphasizes that ED diagnosis based on phenotype alone is challenging and that exome/genome analysis improves diagnostic accuracy—supporting the shift toward molecular confirmation in rare EDs. (peschel2022molecularpathwaybasedclassification pages 1-2)
References
(shimomura2010mutationsinthe pages 1-2): Yutaka Shimomura, Muhammad Wajid, Mazen Kurban, Nobuyuki Sato, and Angela M. Christiano. Mutations in the keratin 85 (krt85/hhb5) gene underlie pure hair and nail ectodermal dysplasia. The Journal of investigative dermatology, 130 3:892-5, Mar 2010. URL: https://doi.org/10.1038/jid.2009.341, doi:10.1038/jid.2009.341. This article has 50 citations.
(amico2019compoundheterozygosityfor pages 1-3): S. Amico, C. Ged, A. Taïeb, and F. Morice‐Picard. Compound heterozygosity for novel krt85 variants associated with pure hair and nail ectodermal dysplasia. Journal of the European Academy of Dermatology and Venereology, Jul 2019. URL: https://doi.org/10.1111/jdv.15777, doi:10.1111/jdv.15777. This article has 7 citations and is from a domain leading peer-reviewed journal.
(naeem2006amutationin pages 1-2): M. Naeem, M. Wajid, K. Lee, S. Leal, and W. Ahmad. A mutation in the hair matrix and cuticle keratin krthb5 gene causes ectodermal dysplasia of hair and nail type. Journal of Medical Genetics, 43:274-279, Aug 2006. URL: https://doi.org/10.1136/jmg.2005.033381, doi:10.1136/jmg.2005.033381. This article has 72 citations and is from a domain leading peer-reviewed journal.
(naeem2006amutationin pages 3-4): M. Naeem, M. Wajid, K. Lee, S. Leal, and W. Ahmad. A mutation in the hair matrix and cuticle keratin krthb5 gene causes ectodermal dysplasia of hair and nail type. Journal of Medical Genetics, 43:274-279, Aug 2006. URL: https://doi.org/10.1136/jmg.2005.033381, doi:10.1136/jmg.2005.033381. This article has 72 citations and is from a domain leading peer-reviewed journal.
(lin2012lossoffunctionmutationsin pages 1-2): Zhimiao Lin, Quan Chen, Lei Shi, Mingyang Lee, Kathrin A. Giehl, Zhanli Tang, Huijun Wang, Jie Zhang, Jinghua Yin, Lingshen Wu, Ruo Xiao, Xuanzhu Liu, Lanlan Dai, Xuejun Zhu, Ruoyu Li, Regina C. Betz, Xue Zhang, and Yong Yang. Loss-of-function mutations in hoxc13 cause pure hair and nail ectodermal dysplasia. American journal of human genetics, 91 5:906-11, Nov 2012. URL: https://doi.org/10.1016/j.ajhg.2012.08.029, doi:10.1016/j.ajhg.2012.08.029. This article has 87 citations and is from a highest quality peer-reviewed journal.
(naeem2006amutationin pages 2-3): M. Naeem, M. Wajid, K. Lee, S. Leal, and W. Ahmad. A mutation in the hair matrix and cuticle keratin krthb5 gene causes ectodermal dysplasia of hair and nail type. Journal of Medical Genetics, 43:274-279, Aug 2006. URL: https://doi.org/10.1136/jmg.2005.033381, doi:10.1136/jmg.2005.033381. This article has 72 citations and is from a domain leading peer-reviewed journal.
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