Keratosis Pilaris Atrophicans: Comprehensive Disease-Characteristics Report

Executive summary and evidence limits

Keratosis pilaris atrophicans (KPA) is best treated as a clinically defined, genetically heterogeneous spectrum, not as one molecular disease. Its shared sequence is follicular keratin plugging and perifollicular erythema/inflammation followed by follicular destruction, atrophy, scarring, and permanent hair loss. The conventional forms are (1) keratosis pilaris atrophicans faciei (KPAF), often equated with ulerythema ophryogenes (UO); (2) atrophoderma vermiculatum/vermiculata (AV); and (3) keratosis follicularis spinulosa decalvans (KFSD). Boundaries overlap, and some classifications distinguish KPAF from UO more narrowly by facial distribution. (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3, alessandrini2021theroleof pages 4-5)

Only X-linked KFSD has a well-supported recurrent molecular cause, MBTPS2. UO is strongly enriched in RAS/MAPK disorders but an isolated UO diagnosis does not imply that a RASopathy gene is causal. AV remains largely a clinicopathologic diagnosis with uncertain genetic architecture. Most therapeutic evidence consists of case reports or small uncontrolled series; no KPA-specific randomized trial was identified.

Table: This compact table summarizes the keratosis pilaris atrophicans spectrum and separates clinically defined entities from the genetically established MBTPS2-associated KFSD subtype. It is useful for disease knowledge-base curation because it aligns phenotype, course, genetics, diagnostics, treatment evidence, and uncertainty in one place.

1. Disease information

Definition and subtypes

• KPAF/UO: inflammatory keratotic papules begin chiefly in the lateral eyebrows, extend medially, and may involve cheeks, temples, forehead, or rarely scalp. Progressive scarring causes lateral-eyebrow loss and sometimes complete eyebrow alopecia; eyelashes are generally spared in classical UO. (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3, jansen2003atrophodermiavermiculatacase pages 1-3)
• AV: symmetric preauricular/cheek follicular papules evolve into reticulated, pitted “worm-eaten” or “honey-combed” atrophy. Synonyms include atrophoderma reticulatum and folliculitis erythematosa reticulata. (stojanovic2015overlapbetweenulerythema pages 3-5, bari2017atrophodermavermiculataa pages 1-3)
• KFSD: the most extensive form, with generalized follicular hyperkeratosis and progressive cicatricial alopecia of scalp, eyebrows, and eyelashes; facial erythema, photophobia, ocular inflammation, palmoplantar keratoderma, xerosis, atopy, nail dystrophy, or dental abnormalities may coexist. (stojanovic2015overlapbetweenulerythema pages 3-5, alessandrini2021theroleof pages 4-5, alessandrini2021theroleof pages 1-2)

Identifiers and coding

• OMIM: X-linked KFSD is MIM 308800. (bornholdt2013genotype–phenotypecorrelationsemerging pages 2-3)
• MONDO: a precise umbrella-level MONDO identifier was not verified in the retrieved primary literature and should be resolved directly against the current MONDO release before ingestion. Do not substitute the code for ordinary keratosis pilaris.
• ICD: no dedicated ICD-10-CM or ICD-11 code was established from the retrieved sources. In practice, coding may fall under “other specified epidermal thickening/disorder of keratinization” and/or cicatricial alopecia, but jurisdiction-specific verification is required.
• MeSH: dedicated indexing for the umbrella disorder was not established; publications are commonly indexed through keratosis pilaris, keratinization disorders, atrophy, or cicatricial alopecia.

This report synthesizes aggregated disease-level literature, including family studies, case reports, reviews, and a mutation-positive syndromic cohort. It is not derived from individual EHR records.

2. Etiology, risk, protection, and gene–environment interaction

KPA is a congenital/developmental follicular keratinization spectrum. The proximal lesion is abnormal keratinization in and around the pilosebaceous follicle, followed by plugging, inflammation, follicular atrophy, and fibrosis. (stojanovic2015overlapbetweenulerythema pages 1-3, jansen2003atrophodermiavermiculatacase pages 1-3)

Genetic causes and susceptibility

• KFSD: hemizygous germline missense variants in MBTPS2, an X-chromosomal gene encoding site-2 protease, are established causes of X-linked KFSD. A study of 15 affected males from 13 unrelated families found 11 missense variants, seven novel. Variant NM_015884:c.1523A>G, p.(Asn508Ser) caused a comparatively mild KFSD phenotype in three unrelated families. Other reported substitutions across the MBTPS2 phenotypic spectrum include p.Met87Ile, p.Phe475Ser, p.Leu476Ser, p.Asp477Val, p.Gly500Asp, and p.Asn508Ser. (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2, bornholdt2013genotype–phenotypecorrelationsemerging pages 7-8, bornholdt2013genotype–phenotypecorrelationsemerging pages 2-3, bornholdt2013genotype–phenotypecorrelationsemerging pages 3-4)
• UO/KPAF: familial autosomal-dominant transmission with variable penetrance has been described, but no single recurrent causal gene for isolated UO was established in the retrieved evidence. UO is a strong cutaneous marker of RAS/MAPK dysregulation: in a cohort of 61 molecularly confirmed cardio-facio-cutaneous syndrome patients with BRAF, MAP2K1, MAP2K2, or KRAS variants, 55/61 (90%) had UO. (stojanovic2015overlapbetweenulerythema pages 1-3, siegel2011dermatologicalfindingsin pages 1-3)
• A 17-year-old with 46,XY gonadal dysgenesis and MAP3K1 c.1016G>A, p.Arg339Gln also had UO. This single case establishes an association, not proof that MAP3K1 generally causes isolated UO. (nimgaonkar2022ulerythemaophryogenesin pages 1-3)
• AV: proposed chromosomal associations, including 18p deletion, are historical and not sufficient to define a recurrent AV locus. Its isolated genetic cause remains unresolved. (bari2017atrophodermavermiculataa pages 1-3)

No reproducible modifier genes, protective variants, founder alleles, carrier frequency, or population allele-frequency estimates were identified. Reported MBTPS2 variants should be checked individually in current ClinVar and gnomAD releases; the source studies do not supply ACMG/AMP classifications or population frequencies. The disease variants described are constitutional/germline, not somatic.

Environmental and protective factors

No toxin, infection, radiation exposure, occupation, diet, smoking, alcohol, exercise pattern, or lifestyle behavior is established as causal. No validated genetic or environmental protective factor exists. Dryness or irritation may plausibly accentuate follicular roughness, but evidence that these alter the scarring natural history is lacking. Accordingly, a formal gene–environment interaction has not been demonstrated.

3. Phenotypes

Core manifestations and suggested HPO annotations

• Follicular hyperkeratosis/keratosis pilaris — physical sign; onset in infancy or childhood; often widespread in KFSD. Suggested HPO: Keratosis pilaris, HP:0002209.
• Perifollicular/facial erythema — inflammatory sign; prominent in active UO and KFSD; may diminish after puberty.
• Sparse or absent eyebrows/madarosis — early lateral eyebrow loss in UO, broader involvement in KFSD. Suggested HPO: Sparse eyebrow, HP:0000535 or the current HPO child term for eyebrow alopecia after release verification.
• Cicatricial alopecia — progressive and irreversible once follicles are replaced by fibrosis; chiefly scalp in KFSD. Suggested HPO: Scarring alopecia, HP:0004552, subject to current-release verification.
• Eyelash alopecia — supports KFSD rather than classical UO. Suggested HPO: Sparse eyelashes/eyelash alopecia.
• Cutaneous facial atrophy and pitted scars — dominant AV phenotype; slowly progressive. Suggested HPO: Cutaneous atrophy and Abnormality of facial skin.
• Photophobia and keratoconjunctival inflammation — variable KFSD-associated manifestations. Suggested HPO: Photophobia, HP:0000613 and Keratitis/Conjunctivitis.
• Palmoplantar keratoderma, ichthyosiform xerosis, nail dystrophy, dental abnormalities, and atopic dermatitis — uncommon/variable KFSD-associated findings. (stojanovic2015overlapbetweenulerythema pages 3-5, alessandrini2021theroleof pages 1-2)

UO commonly begins at birth or soon afterward; KFSD begins in infancy or childhood, with scalp disease becoming conspicuous in childhood or early adolescence; AV generally begins in childhood. Severity is variable. UO and KFSD often progress until puberty and then stabilize or become less inflammatory, but alopecia and atrophy remain. (stojanovic2015overlapbetweenulerythema pages 1-3, alessandrini2021theroleof pages 4-5, nimgaonkar2022ulerythemaophryogenesin pages 1-3, bari2017atrophodermavermiculataa pages 1-3)

Reliable frequencies for isolated KPA manifestations are unavailable. The strongest quantitative datum is syndromic: UO in 90% (55/61) of mutation-positive CFC patients, which must not be generalized to isolated KPA. (siegel2011dermatologicalfindingsin pages 1-3)

Quality of life

No validated KPA-specific EQ-5D, SF-36, PROMIS, or dermatology-quality-of-life cohort was identified. The principal expected burden is visible facial/scalp scarring, eyebrow/eyelash loss, cosmetic disfigurement, and—in KFSD with ocular disease—photophobia. AV has explicitly been described as a rare “disfiguring” condition, but this is descriptive rather than instrument-based evidence. (bari2017atrophodermavermiculataa pages 1-3)

4. Genetic and molecular information

MBTPS2 and pathogenic mechanism

MBTPS2 encodes an endoplasmic-reticulum/Golgi membrane zinc metalloprotease, site-2 protease (S2P), required for regulated intramembrane proteolysis. After site-1 cleavage, S2P releases membrane-bound transcription factors controlling sterol homeostasis, lipid metabolism, ER-stress responses, and differentiation, including SREBP, ATF6, and OASIS-family proteins. (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2, lim2021omicsprofilingof pages 2-4)

Pathogenic substitutions cluster in transmembrane domains. Changes near the catalytic site reduce activity most severely; residual activity correlates with phenotype. N- or C-terminal variants retaining more activity tend to produce milder disease, whereas transmembrane-domain 6–8 hotspots can eliminate approximately two-thirds of catalytic activity and cause severe developmental/ichthyotic phenotypes. p.Asn508Ser is associated with mild KFSD and progressive alopecia. Female expression is influenced by X-chromosome inactivation. (bornholdt2013genotype–phenotypecorrelationsemerging pages 7-8)

No dominant-negative mechanism is established; the evidence supports partial loss of catalytic function/hypomorphic dysfunction. Whole-gene deletions, recurrent splice variants, repeat expansions, mitochondrial variants, and disease-specific epigenetic abnormalities were not established.

5. Environmental information

KPA is not infectious or transmissible, and no microbial trigger is recognized. There is no evidence for pollution, toxins, ultraviolet exposure, occupational exposure, diet, smoking, alcohol, or exercise as causal factors. Standard skin care may reduce roughness and irritation but is supportive rather than disease-preventing. CTD-style chemical associations, validated gene–environment effects, and exposure-response data are absent.

6. Mechanism and pathophysiology

Causal chain

1. Upstream inherited defect: an MBTPS2 missense variant in X-linked KFSD reduces S2P activity; in syndromic UO, upstream germline RAS/MAPK activation is associated with abnormal ectodermal development, although the direct follicular chain is unresolved. (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2, siegel2011dermatologicalfindingsin pages 1-3)
2. Molecular dysfunction: defective regulated intramembrane proteolysis impairs activation of SREBP/ATF6/OASIS-related transcriptional programs, disturbing lipid/sterol homeostasis, ER-stress adaptation, and epidermal differentiation. Patient fibroblasts carrying p.Arg429His or p.Asn508Ser showed impaired OASIS cleavage and diminished induced ATF6/SREBP activities. (lim2021omicsprofilingof pages 2-4)
3. Cellular/tissue lesion: abnormal follicular keratinization plugs the infundibulum, producing dilated keratin-filled follicles and perifollicular lymphocytic inflammation. (stojanovic2015overlapbetweenulerythema pages 1-3)
4. Downstream irreversible damage: chronic folliculocentric inflammation causes infundibular atrophy, sebaceous-gland and follicular-unit loss, and perifollicular/diffuse dermal fibrosis. (stojanovic2015overlapbetweenulerythema pages 5-7, alessandrini2021theroleof pages 4-5, bari2017atrophodermavermiculataa pages 1-3)
5. Clinical manifestation: rough keratotic papules and erythema evolve into eyebrow/eyelash/scalp alopecia or reticulated facial atrophy, depending on anatomical distribution and disease subtype.

Suggested annotations

• GO biological process: regulated intramembrane proteolysis; cholesterol homeostasis; lipid metabolic process; response to endoplasmic-reticulum stress; epidermal-cell differentiation; keratinization; inflammatory response; wound healing/fibrosis.
• GO molecular function: metalloendopeptidase activity; zinc-ion binding.
• GO cellular component: endoplasmic-reticulum membrane; Golgi membrane; integral component of membrane.
• Cell Ontology: keratinocyte, hair-follicle keratinocyte, dermal fibroblast, sebocyte, and perifollicular lymphocyte. Exact CL identifiers should be release-verified.

Molecular profiling and advanced technologies

The principal profiling study used primary skin fibroblasts from four controls, three MBTPS2-osteogenesis-imperfecta patients, and two MBTPS2-IFAP/KFSD patients, with RNA sequencing, lipid analysis, electron microscopy, and immunofluorescence. The dermatologic group included p.Arg429His and p.Asn508Ser. This establishes pathway-level dysfunction but is underpowered for a KFSD-specific molecular signature. No KPA-specific single-cell atlas, spatial transcriptomic dataset, proteomic signature, metabolomic biomarker, organoid, or CRISPR screen was identified. (lim2021omicsprofilingof pages 2-4)

7. Anatomical structures affected

The primary organ is skin, specifically the pilosebaceous unit and hair follicles.

• UO: bilateral lateral eyebrows, then medial eyebrows, cheeks, temples, and occasionally forehead/scalp.
• AV: bilateral preauricular and malar cheek skin.
• KFSD: scalp, eyebrows, eyelashes, face, and variably trunk/extensor limbs; cornea and conjunctiva may be secondarily involved.
• Tissue/cell level: follicular epithelium/infundibulum, sebaceous glands, perifollicular dermis, keratinocytes, sebocytes, fibroblasts, and inflammatory lymphocytes.
• Subcellular level: ER and Golgi membranes are central to MBTPS2/S2P biology.

Suggested UBERON labels are skin of face, cheek, eyebrow, eyelid/eyelash region, scalp, hair follicle, sebaceous gland, cornea, and conjunctiva. Disease is generally bilateral and symmetric in UO/AV; focal or patchy scalp alopecia can occur in KFSD. (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3)

8. Temporal development

Onset is congenital, neonatal, or early pediatric rather than adult-acquired. The onset is insidious and chronic. Active stages feature follicular papules and erythema; intermediate disease adds follicular atrophy and hair loss; advanced disease contains established fibrosis, absent follicular ostia, and irreversible scarring. UO/KFSD often progress until puberty and subsequently stabilize, while AV usually worsens slowly. Inflammation can remit spontaneously or with treatment, but destroyed follicles do not regenerate. (stojanovic2015overlapbetweenulerythema pages 1-3, stojanovic2015overlapbetweenulerythema pages 5-7, nimgaonkar2022ulerythemaophryogenesin pages 1-3, bari2017atrophodermavermiculataa pages 1-3)

The critical therapeutic window is therefore the active inflammatory stage before fibrosis, although this inference has not been tested prospectively.

9. Inheritance and population

• KFSD: usually X-linked, often described as X-linked dominant or X-linked with sex-modified expression. Hemizygous males are typically more severely affected; heterozygous females can be asymptomatic or mildly affected because of lyonization. Autosomal-dominant and sporadic KFSD-like cases have also been reported. (alessandrini2021theroleof pages 3-4, alessandrini2021theroleof pages 1-2, bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2)
• UO: sporadic and autosomal-dominant families with variable penetrance occur. Syndromic UO follows the inheritance of the causal syndrome, commonly autosomal-dominant/de novo RASopathy inheritance. (stojanovic2015overlapbetweenulerythema pages 1-3, siegel2011dermatologicalfindingsin pages 1-3)
• AV: familial cases support a genodermatosis, but the mode and locus remain uncertain.

No robust prevalence, incidence, geographic distribution, ethnicity effect, carrier frequency, founder effect, anticipation, germline-mosaicism rate, or consanguinity association was found. “Rare” or “exceedingly rare” is currently more defensible than a cases-per-100,000 estimate. There is no established sex imbalance for the umbrella spectrum; male predominance/severity applies chiefly to X-linked KFSD.

10. Diagnostics

Clinical assessment

Diagnosis starts with age of onset, distribution, inflammatory activity, scarring, family history, and associated ocular or syndromic findings. There are no validated standardized criteria or circulating biomarkers. Routine blood/urine tests and radiologic imaging are not diagnostic.

Trichoscopy in KFSD can show diffuse perifollicular hyperkeratosis, absent follicular ostia, tufting, elongated vessels, yellow dots, and dystrophic eyebrow/eyelash hairs. Evidence is very limited—the 2021 report described itself as the first trichoscopic evaluation. (alessandrini2021theroleof pages 3-4, alessandrini2021theroleof pages 4-5)

Histopathology: early lesions show dilated keratin-filled follicles and perifollicular lymphocytes. Progressive lesions show infundibular atrophy, reduced sebaceous glands and follicular units, and perifollicular or diffuse fibrosis. AV similarly progresses from follicular plugging/inflammation to pilosebaceous atrophy and dermal fibrosis. (stojanovic2015overlapbetweenulerythema pages 1-3, alessandrini2021theroleof pages 4-5, bari2017atrophodermavermiculataa pages 1-3)

Genetic testing

• In a male with KFSD, test MBTPS2 by sequencing with deletion/duplication analysis. A genodermatosis/cicatricial-alopecia panel or WES is appropriate for atypical/negative cases because phenocopies and overlapping MBTPS2 disorders exist.
• In UO with congenital heart disease, short stature, dysmorphism, developmental disability, lymphatic disease, or widespread ectodermal findings, use a RASopathy panel including BRAF, KRAS, MAP2K1, MAP2K2, SOS1, SOS2, and other current genes. UO alone is insufficient evidence for such a molecular diagnosis. The 90% frequency in CFC makes it a useful syndromic clue. (siegel2011dermatologicalfindingsin pages 1-3)
• CMA is reasonable when developmental anomalies suggest a copy-number disorder. Karyotype/FISH, mitochondrial sequencing, and repeat-expansion testing are not routine KPA tests. WGS may be considered after nondiagnostic panel/WES but has no established incremental KPA yield.
• Confirm the variant with an accredited laboratory, perform segregation analysis where possible, and interpret under ACMG/AMP standards.

Differential diagnosis

Differentials include ordinary nonatrophic keratosis pilaris; keratosis pilaris rubra; folliculitis decalvans; lichen planopilaris; frontal fibrosing alopecia; IFAP syndrome; keratitis–ichthyosis–deafness syndrome; atrichia with papular lesions; hereditary mucoepithelial dystrophy; acne or varicella scars; focal dermal hypoplasia; and other varioliform atrophodermas. Loss of follicular ostia and fibrosis distinguish cicatricial disease; eyelash/scalp scarring favors KFSD, whereas lateral eyebrow-predominant disease favors UO and reticulated cheek pits favor AV. (alessandrini2021theroleof pages 4-5)

No population, newborn, or carrier-screening program exists. Cascade testing is appropriate only after a familial pathogenic variant is established.

11. Outcome and prognosis

KPA is not known to reduce survival or life expectancy; disease-specific mortality has not been reported. Morbidity is dermatologic and cosmetic, with photophobia/ocular inflammation adding functional burden in KFSD. The active inflammatory component may improve after puberty or treatment, but established alopecia and pitted atrophy are generally permanent. (stojanovic2015overlapbetweenulerythema pages 5-7, nimgaonkar2022ulerythemaophryogenesin pages 1-3)

Poorer outcome is expected with extensive scalp involvement, eyelash loss, prolonged inflammation, or delayed control before fibrosis. These are clinically plausible prognostic features, not validated predictors. No prognostic molecular biomarker or survival model exists.

12. Treatment

There is no curative or regulatory-approved disease-modifying therapy. Management aims to reduce plugging and inflammation before scarring, treat ocular disease, and improve appearance.

Practical strategy

1. Baseline care: gentle cleanser, regular emollient, and avoidance of abrasive manipulation.
2. Follicular plugging: topical urea, lactic/glycolic acid, salicylic acid, or topical retinoid. Suggested CHEBI concepts include urea, lactic acid, salicylic acid, and tretinoin; NCIT intervention concepts: topical therapy, keratolytic therapy.
3. Active inflammation: brief low-potency topical corticosteroid on facial disease; tetracycline-class anti-inflammatory therapy has been reported but lacks controlled evidence. A UO case used adapalene plus desonide and hydroxy-acid emollient without significant change at three months, complicated by poor adherence. (nimgaonkar2022ulerythemaophryogenesin pages 3-4, nimgaonkar2022ulerythemaophryogenesin pages 1-3)
4. Progressive KFSD/AV: consider a systemic retinoid under specialist monitoring. In one KFSD case, isotretinoin 0.3 mg/kg/day for six months plus keratolytic cream produced complete facial resolution and scalp improvement; subsequent 5% minoxidil twice daily increased hair density. No adverse effects were reported, but this is one patient. (alessandrini2021theroleof pages 3-4)
5. Vascular erythema: 595-nm pulsed-dye laser has the best small-series signal: among ten UO patients, three achieved complete resolution and seven had >75% improvement, primarily in erythema. This does not establish reversal of scarring or hair regrowth. (nimgaonkar2022ulerythemaophryogenesin pages 3-4)
6. Established texture/atrophy: AV case literature describes partial response to 35% trichloroacetic-acid peels plus 0.05% tretinoin and reports use of CO2 or 585-nm PDL, dermabrasion, cryotherapy, and isotretinoin for active inflammation. Long-term efficacy is unknown. (bari2017atrophodermavermiculataa pages 1-3)
7. Residual alopecia: camouflage, cosmetic eyebrow techniques, minoxidil where viable follicles remain, and selected hair transplantation only after prolonged disease inactivity. Ophthalmology should manage photophobia, keratitis, or conjunctivitis.

Potential adverse effects include irritant dermatitis from acids/retinoids, steroid atrophy, retinoid teratogenicity and mucocutaneous/laboratory toxicity, minoxidil irritation/hypertrichosis, and laser-associated pain, pigment alteration, or scarring. No KPA pharmacogenomic guidance exists. There is no gene, cell, RNA, CRISPR, targeted kinase, or immunotherapy in clinical use.

ClinicalTrials.gov searching retrieved studies for ordinary keratosis pilaris—including diode/Nd:YAG/thulium laser, emollient, and cosmetic interventions—but none was established as enrolling KPA/UO/AV/KFSD specifically. These should not be represented as disease-specific KPA trials.

13. Prevention

Primary prevention is unavailable because the disease is inherited/developmental; vaccines, prophylactic drugs, and public-health/environmental interventions are not applicable. Secondary/tertiary prevention consists of early recognition, minimizing follicular inflammation before fibrosis, ophthalmologic surveillance when indicated, and screening syndromic UO patients for associated RASopathy manifestations. A report specifically advocated improved UO recognition in RASopathy patients to permit intervention before permanent scarring. (nimgaonkar2022ulerythemaophryogenesin pages 3-4)

For molecularly confirmed families, genetic counseling should cover subtype-specific inheritance, variable expression, recurrence risk, cascade testing, and reproductive options, including prenatal or preimplantation testing when desired. Females carrying an MBTPS2 variant may be mildly affected or nonpenetrant. (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2)

14. Other species and natural disease

No verified naturally occurring KPA, UO, AV, or KFSD orthologous syndrome was identified in companion animals, livestock, or wildlife. Consequently, no breed/VBO annotation, veterinary prevalence, zoonotic potential, or cross-species transmission applies. MBTPS2 is evolutionarily conserved, but conservation alone is not evidence of a natural veterinary counterpart.

15. Model organisms and experimental models

No validated mouse, rat, zebrafish, Drosophila, or other organismal model was found that demonstrably reproduces the human combination of follicular keratosis and progressive cicatricial alopecia. The most directly relevant experimental systems are patient-derived dermal fibroblasts carrying MBTPS2 variants. These support defective S2P-dependent transcription-factor activation and permit transcriptomic/lipid/ER-stress assays, but fibroblasts do not reproduce hair-follicle architecture, keratin plugging, immune–epithelial interactions, or scarring alopecia. (lim2021omicsprofilingof pages 2-4)

Future models should use variant-specific knock-in animals, human hair-follicle organoids, or isogenic iPSC-derived keratinocyte–sebocyte–fibroblast systems. Applications would include mapping SREBP/ATF6/OASIS defects to follicular differentiation, defining inflammatory-to-fibrotic transitions, and testing whether early pathway correction prevents permanent follicular loss.

Recent developments and authoritative interpretation

The 2023–2024 literature did not materially change KPA-specific molecular diagnosis or treatment. The most informative contemporary evidence remains: patient-fibroblast molecular profiling (2021), trichoscopy plus a dose-specific KFSD treatment report (2021), and the MAP3K1-associated UO case with a summary of laser evidence (2022). The major current interpretation is therefore conservative: MBTPS2 testing is justified for KFSD; UO should trigger assessment for a RASopathy when systemic clues are present; and early anti-keratinizing/anti-inflammatory therapy is rational but unproven to prevent scarring. (lim2021omicsprofilingof pages 2-4, siegel2011dermatologicalfindingsin pages 1-3, alessandrini2021theroleof pages 3-4, nimgaonkar2022ulerythemaophryogenesin pages 3-4)

Selected exact source language

• Stojanović et al. describe KPA lesions as follicular keratotic papules that “eventually result in fibrosis, atrophy, progressive scarring and permanent hair loss.” Publication: September 2015; https://doi.org/10.1515/sjdv-2015-0012. (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3)
• The 2021 KFSD report defines the disorder as a rare hereditary keratinization disease with “progressive scarring alopecia of scalp, eyebrows, and eyelashes.” Publication: October 2021; https://doi.org/10.1159/000510525. (alessandrini2021theroleof pages 1-2)
• The AV abstract describes a “rare genodermatosis with usual onset in childhood” and “honey-combed” cheek atrophy, with a “generally slow” progressive course. Publication: January 2017; https://doi.org/10.66344/jpad.v13i4.765. (bari2017atrophodermavermiculataa pages 1-3)

PMIDs were not consistently exposed in the retrieved records; DOI URLs and publication dates are therefore supplied rather than inventing unverified PMID values. Before production ingestion, identifiers—including MONDO, HPO IDs, HGNC ID for MBTPS2, current ClinVar assertions, and ICD mappings—should be programmatically validated against their current releases.

References

1. (stojanovic2015overlapbetweenulerythema pages 3-5): Slobodan Stojanović, Nada Vučković, and Marina Jovanović. Overlap between ulerythema ophryogenes and keratosis follicularis spinulosa decalvans: a case report. Serbian Journal of Dermatology and Venereology, 7:129-138, Sep 2015. URL: https://doi.org/10.1515/sjdv-2015-0012, doi:10.1515/sjdv-2015-0012. This article has 1 citations.

2. (stojanovic2015overlapbetweenulerythema pages 1-3): Slobodan Stojanović, Nada Vučković, and Marina Jovanović. Overlap between ulerythema ophryogenes and keratosis follicularis spinulosa decalvans: a case report. Serbian Journal of Dermatology and Venereology, 7:129-138, Sep 2015. URL: https://doi.org/10.1515/sjdv-2015-0012, doi:10.1515/sjdv-2015-0012. This article has 1 citations.

3. (alessandrini2021theroleof pages 4-5): Aurora Alessandrini, Giancarlo Brattoli, Bianca Maria Piraccini, Ambra Di Altobrando, and Michela Starace. The role of trichoscopy in keratosis follicularis spinulosa decalvans: case report and review of the literature. Skin Appendage Disorders, 7:29-35, Oct 2021. URL: https://doi.org/10.1159/000510525, doi:10.1159/000510525. This article has 11 citations and is from a peer-reviewed journal.

4. (stojanovic2015overlapbetweenulerythema pages 5-7): Slobodan Stojanović, Nada Vučković, and Marina Jovanović. Overlap between ulerythema ophryogenes and keratosis follicularis spinulosa decalvans: a case report. Serbian Journal of Dermatology and Venereology, 7:129-138, Sep 2015. URL: https://doi.org/10.1515/sjdv-2015-0012, doi:10.1515/sjdv-2015-0012. This article has 1 citations.

5. (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.

6. (nimgaonkar2022ulerythemaophryogenesin pages 3-4): Ila Nimgaonkar, Marielle Jamgochian, David M. Milgraum, Amy S. Pappert, and Sandy S. Milgraum. Ulerythema ophryogenes in association with map3k1-mutated swyer syndrome. Jul 2022. URL: https://doi.org/10.1016/j.jdcr.2022.05.008, doi:10.1016/j.jdcr.2022.05.008. This article has 2 citations.

7. (bari2017atrophodermavermiculataa pages 1-3): Arfan ul Bari. Atrophoderma vermiculata: a rare disfiguring condition. Journal of Pakistan Association of Dermatologists, 13(4):208-210, Jan 2017. URL: https://doi.org/10.66344/jpad.v13i4.765, doi:10.66344/jpad.v13i4.765. This article has 1 citations.

8. (jansen2003atrophodermiavermiculatacase pages 1-3): T. Jansen, C. Sander, and P. Altmeyer. Atrophodermia vermiculata: case report and review of the literature. Journal of the European Academy of Dermatology and Venereology, 17:70-72, Jan 2003. URL: https://doi.org/10.1046/j.1468-3083.2003.00517.x, doi:10.1046/j.1468-3083.2003.00517.x. This article has 15 citations and is from a domain leading peer-reviewed journal.

9. (nimgaonkar2022ulerythemaophryogenesin pages 1-3): Ila Nimgaonkar, Marielle Jamgochian, David M. Milgraum, Amy S. Pappert, and Sandy S. Milgraum. Ulerythema ophryogenes in association with map3k1-mutated swyer syndrome. Jul 2022. URL: https://doi.org/10.1016/j.jdcr.2022.05.008, doi:10.1016/j.jdcr.2022.05.008. This article has 2 citations.

10. (siegel2011dermatologicalfindingsin pages 1-3): D.H. Siegel, J. McKenzie, I.J. Frieden, and K.A. Rauen. Dermatological findings in 61 mutation‐positive individuals with cardiofaciocutaneous syndrome. British Journal of Dermatology, 164:no-no, Jan 2011. URL: https://doi.org/10.1111/j.1365-2133.2010.10122.x, doi:10.1111/j.1365-2133.2010.10122.x. This article has 123 citations and is from a highest quality peer-reviewed journal.

11. (alessandrini2021theroleof pages 3-4): Aurora Alessandrini, Giancarlo Brattoli, Bianca Maria Piraccini, Ambra Di Altobrando, and Michela Starace. The role of trichoscopy in keratosis follicularis spinulosa decalvans: case report and review of the literature. Skin Appendage Disorders, 7:29-35, Oct 2021. URL: https://doi.org/10.1159/000510525, doi:10.1159/000510525. This article has 11 citations and is from a peer-reviewed journal.

12. (alessandrini2021theroleof pages 1-2): Aurora Alessandrini, Giancarlo Brattoli, Bianca Maria Piraccini, Ambra Di Altobrando, and Michela Starace. The role of trichoscopy in keratosis follicularis spinulosa decalvans: case report and review of the literature. Skin Appendage Disorders, 7:29-35, Oct 2021. URL: https://doi.org/10.1159/000510525, doi:10.1159/000510525. This article has 11 citations and is from a peer-reviewed journal.

13. (bornholdt2013genotype–phenotypecorrelationsemerging pages 7-8): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.

14. (bornholdt2013genotype–phenotypecorrelationsemerging pages 2-3): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.

15. (ming2009ichthyosisfollicularisalopecia pages 1-3): Andrew Ming, Rudolf Happle, Karl‐Heinz Grzeschik, and Gayle Fischer. Ichthyosis follicularis, alopecia, and photophobia (ifap) syndrome due to mutation of the gene mbtps2 in a large australian kindred. Pediatric Dermatology, 26:427-431, Jul 2009. URL: https://doi.org/10.1111/j.1525-1470.2009.00946.x, doi:10.1111/j.1525-1470.2009.00946.x. This article has 22 citations and is from a peer-reviewed journal.

16. (bornholdt2013genotype–phenotypecorrelationsemerging pages 3-4): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.

17. (lim2021omicsprofilingof pages 2-4): Pei Jin Lim, Severin Marfurt, Uschi Lindert, Lennart Opitz, Timothée Ndarugendamwo, Pakeerathan Srikanthan, Martin Poms, Martin Hersberger, Claus-Dieter Langhans, Dorothea Haas, Marianne Rohrbach, and Cecilia Giunta. Omics profiling of s2p mutant fibroblasts as a mean to unravel the pathomechanism and molecular signatures of x-linked mbtps2 osteogenesis imperfecta. Frontiers in Genetics, May 2021. URL: https://doi.org/10.3389/fgene.2021.662751, doi:10.3389/fgene.2021.662751. This article has 7 citations and is from a peer-reviewed journal.

Artifacts

• Edison artifact artifact-00

Reference Validation

Checked with linkml-reference-validator 0.2.1.

References that may not be about this subject

These identifiers resolve, so they are not fabrications, but the records they resolve to share almost none of this report's vocabulary. That is a clue and not a verdict - a paper can be relevant in ways its title and abstract do not spell out - so read them before deciding:

• DOI:10.66344/jpad.v13i4.765 (5 mentions) - Atrophoderma vermiculata: A rare disfiguring condition
• shared terms: atrophy

Weighed against this report's own most characteristic terms: disease, kfsd, gene, clinical, follicular, genetic, scarring, variant, alopecia, molecular, loss, inflammation, fibrosis, atrophy, mbtps2, established, keratosis, treatment, scalp, eyelash.

All extracted references resolved successfully. Resolving is not the same as being relevant, though - see the references listed above as possibly off topic.