| Domain | Evidence-backed findings | Quantitative data / representative variants | Suggested ontology terms |
|---|---|---|---|
| Disease identity | **Autosomal dominant cutis laxa 1 (ADCL1)** is an ELN-related systemic elastinopathy characterized by loose, inelastic skin and variable cardiovascular and pulmonary disease. Evidence is primarily aggregated from cohorts, families, and case reports rather than EHR-derived datasets. **OMIM: 123700**; MONDO, Orphanet, MeSH, and disease-specific ICD identifiers require direct database verification. (pqac-00000001, pqac-00000004, pqac-00000020) | Largest cited cohort: 20 clinically evaluated individuals, ages 1–84 years. (pqac-00000001) | Autosomal dominant cutis laxa; cutis laxa; elastinopathy; MONDO term to verify |
| Disease boundary | ADCL1 is principally caused by **ELN** variants. It must not be conflated with **FBLN5-related cutis laxa**, which is predominantly autosomal recessive cutis laxa type 1A; FBLN5 is not the established primary cause of ELN-related ADCL1. (pqac-00000000, pqac-00000003, pqac-00000004) | ELN gene OMIM: **130160**. | ELN; elastic-fiber disorder; autosomal recessive cutis laxa type 1A |
| Cutaneous phenotype | Congenital or early-childhood loose, redundant, poorly elastic skin is defining. Disease may be localized or generalized and can become less conspicuous with age. Dermal elastic fibers are reduced, fragmented, branching, or disorganized. (pqac-00000001, pqac-00000009, pqac-00000012, pqac-00000014) | Skin laxity **100%**; generalized/extensive involvement **75%**; localized redundancy **25%** in the 20-person cohort. (pqac-00000001, pqac-00000012) | HPO: Cutis laxa; redundant skin; generalized skin laxity; abnormality of dermal elastic fibers |
| Craniofacial phenotype | Features include a long or coarse prematurely aged face, large pliant ears, long philtrum, beaked nose, ptosis, and blepharochalasis. (pqac-00000000, pqac-00000010, pqac-00000011) | Facial gestalt reported in **100%** in one cohort analysis; the long-face, large-ear, long-philtrum, and beaked-nose combination occurred in approximately **70%**. (pqac-00000000, pqac-00000001) | HPO: Long face; long philtrum; beaked nose; large ears; ptosis; blepharochalasis; prematurely aged appearance |
| Hernias | Inguinal and less frequently umbilical hernias reflect impaired connective-tissue elasticity. (pqac-00000008, pqac-00000013) | Inguinal hernia approximately **50–51%**. (pqac-00000000, pqac-00000001) | HPO: Inguinal hernia; umbilical hernia |
| Cardiovascular phenotype | Aortic-root dilatation is a major complication and may progress during childhood or adolescence. Associated abnormalities include bicuspid aortic valve, mitral-valve prolapse, and other valve defects. (pqac-00000002, pqac-00000013, pqac-00000018) | Aortic-root dilatation **55–57%**; other valve anomalies **38%**; bicuspid aortic valve **5%**. One patient's aortic root progressed from 41 to 45 mm by age 17. (pqac-00000000, pqac-00000013) | HPO: Aortic-root dilatation; ascending-aortic dilatation; bicuspid aortic valve; mitral-valve prolapse |
| Pulmonary phenotype | Pulmonary emphysema and obstructive lung disease can be early and severe. Rare congenital presentations include recurrent pneumothorax and prolonged respiratory support. (pqac-00000008, pqac-00000013) | Emphysema **35–37%**. One child had FEV1/FVC **42.9%** and residual volume **209%** at age 12. (pqac-00000001, pqac-00000013) | HPO: Pulmonary emphysema; obstructive lung disease; pneumothorax; dyspnea |
| Causal variants | Causal variants are heterozygous germline **ELN** alterations, most commonly 3-prime frameshifts in exons 30–34 that produce stable tropoelastin with an abnormal extended C terminus. Splice variants may generate the same downstream frameshift. (pqac-00000000, pqac-00000003, pqac-00000019, pqac-00000022) | Representative variants: **c.2262delA** hotspot, c.2365delC, c.2189delG, c.2142delG, c.2296_2299dupGCAG, c.2333delC, c.2137delG, c.2124del25, c.2323delG (p.Ala775fs), and c.1985delG (p.Gly662Alafs*25). (pqac-00000000, pqac-00000003, pqac-00000009, pqac-00000015) | ELN; germline pathogenic variant; frameshift variant; splice-altering variant; abnormal protein C terminus |
| Allele rarity | Pathogenic alleles are very rare or absent from population reference datasets. Classification should follow ACMG/AMP criteria using phenotype, segregation, population frequency, predicted C-terminal extension, and functional evidence. (pqac-00000009, pqac-00000015) | c.2323delG was absent from ExAC (**60,706** individuals), 1000 Genomes (**2,535**), and a local database (**2,000**); cohort variants were absent from 100 controls. (pqac-00000015, pqac-00000017) | Pathogenic variant; likely pathogenic variant; variant of uncertain significance; ACMG/AMP classification |
| Molecular mechanism | Mutant tropoelastin has increased self-association and globule formation, impaired binding to fibrillin-1 and fibulin-5-containing microfibrils, and reduced deposition of mature insoluble elastin. Incorporation of abnormal protein disrupts elastic-fiber assembly, supporting a **dominant-negative** mechanism with possible toxic gain of function. (pqac-00000002, pqac-00000018, pqac-00000022) | Representative frameshifts generated predicted extensions of approximately **49, 53, or 86 amino acids**. (pqac-00000002) | GO: Elastic-fiber assembly; extracellular-matrix organization; protein self-association; tropoelastin coacervation |
| Downstream biology | Allele-dependent misfolding can cause endoplasmic-reticulum stress, unfolded-protein-response activation, and apoptosis. Increased pSMAD2 suggests enhanced TGF-beta signaling, hypothesized rather than conclusively proven to contribute to emphysema and aortic-root dilation. (pqac-00000002, pqac-00000018) | Exon 30 alleles increased BiP, phosphorylated eIF2-alpha, and caspase-3; exon 32 alleles produced less extensive UPR activation. (pqac-00000002) | GO: Response to endoplasmic-reticulum stress; unfolded protein response; apoptotic process; TGF-beta receptor signaling; SMAD signal transduction |
| Biological modifiers | Alternative ELN splicing and tissue-specific mutant-protein incorporation modify severity. Exon 32 skipping may reduce mutant burden, but exon-specific genotype–phenotype associations remain provisional. (pqac-00000010, pqac-00000016, pqac-00000022) | Exon 32 was absent from approximately **70% of control transcripts** in one study. (pqac-00000016) | GO: Alternative mRNA splicing; nonsense-mediated mRNA decay; tissue-specific gene expression |
| Anatomy and cells | Elastic-fiber-rich skin, aortic wall, cardiac valves, lung parenchyma, and hernia-prone connective tissues are affected. Relevant cells include dermal fibroblasts, vascular smooth-muscle cells, and pulmonary fibroblasts; compartments include the ER, extracellular matrix, microfibrils, and elastic fibers. (pqac-00000006, pqac-00000018) | Elastin constitutes approximately **90%** of mature elastic fibers by mass in the cited review. (pqac-00000006) | CL: Fibroblast; vascular smooth-muscle cell; pulmonary fibroblast. UBERON: Skin; dermis; aortic wall; lung; cardiac valve. GO-CC: Endoplasmic reticulum; extracellular matrix; elastic fiber |
| Inheritance | Inheritance is autosomal dominant; familial vertical transmission and de novo variants are documented. Cutaneous penetrance appears high, while systemic manifestations show marked variable expressivity. Anticipation, founder effects, and germline mosaicism are not established. (pqac-00000003, pqac-00000017, pqac-00000019) | Phenotype transmitted in **20/22 meioses**; five probands in one study had de novo variants. (pqac-00000003, pqac-00000019) | Autosomal dominant inheritance; variable expressivity; de novo variant; penetrance |
| Epidemiology | ADCL1 is exceptionally rare. No reliable population prevalence, incidence, carrier frequency, sex ratio, founder effect, or geographic gradient was identified; evidence consists mainly of small families and case reports. | Largest cited cohort had **20 clinically evaluated patients** from six families plus one sporadic case. (pqac-00000001) | Rare genetic disease; orphan disease |
| Diagnosis | Diagnosis combines congenital or early skin laxity, characteristic facial appearance, family history, systemic assessment, and molecular confirmation. Testing may begin with ELN exons 30–34 but should expand to full ELN analysis or a connective-tissue/cutis-laxa panel; WES or WGS is useful when targeted testing is negative. Skin biopsy is supportive but not required and may correlate poorly with severity. (pqac-00000008, pqac-00000009, pqac-00000010, pqac-00000015) | Histology may show absent, markedly reduced, broken, or disorganized dermal elastic fibers; a severe neonatal case showed only mild rarefaction. (pqac-00000008, pqac-00000009) | ELN sequencing; multigene panel; whole-exome sequencing; whole-genome sequencing; skin biopsy |
| Differential diagnosis | Differential diagnoses include FBLN5-, EFEMP2/FBLN4-, LTBP4-, ATP6V0A2-, and PYCR1-related recessive cutis laxa, Ehlers–Danlos syndromes, arterial-tortuosity syndrome, occipital-horn syndrome, acquired cutis laxa, and progeroid disorders. ELN haploinsufficiency more typically causes supravalvular aortic stenosis, while 7q11.23 deletion causes Williams–Beuren syndrome. (pqac-00000003, pqac-00000005, pqac-00000009, pqac-00000010) | Severe neurologic, ocular, skeletal, gastrointestinal, or generalized arterial disease should prompt reconsideration of the subtype. (pqac-00000003, pqac-00000004) | Ehlers–Danlos syndrome; arterial-tortuosity syndrome; supravalvular aortic stenosis; Williams syndrome; acquired cutis laxa |
| Surveillance | Baseline and lifelong cardiovascular and pulmonary evaluation are recommended. Assessments include echocardiography of the aortic root, ascending aorta, and valves; cross-sectional angiography when indicated; respiratory review; spirometry; lung volumes; and chest CT when clinically justified. Exact intervals are not standardized and require specialist individualization. (pqac-00000001, pqac-00000013, pqac-00000019) | Progressive childhood aortic disease and severe pediatric COPD have been documented. (pqac-00000013) | Echocardiography; magnetic-resonance angiography; computed tomography; spirometry; pulmonary-function testing |
| Treatment | No approved disease-modifying drug, gene therapy, RNA therapy, or genotype-directed treatment exists. Care is supportive and complication-specific. Aortic intervention should use individualized aneurysm risk assessment; emphysema is treated according to respiratory standards. Losartan has been proposed mechanistically but lacks ADCL1-specific efficacy evidence. (pqac-00000000, pqac-00000010, pqac-00000013) | No disease-specific response-rate data or randomized trials were identified. | NCIT labels: Supportive care; cardiovascular surgery; hernia repair; pulmonary rehabilitation; genetic counseling |
| Cutaneous surgery | Rhytidectomy or excision can improve appearance temporarily, but recurrence is common because the underlying elastic-fiber defect persists. Hernias may be repaired when clinically indicated. (pqac-00000009, pqac-00000011, pqac-00000013) | Review of **7 surgical patients** found recurrence within months in **5**; two required more than two operations. One recent case had no recurrence at five months. (pqac-00000009) | NCIT labels: Rhytidectomy; reconstructive surgery; hernia repair |
| Prognosis and quality of life | Prognosis is highly variable. Skin laxity may improve with age, but aortic disease and emphysema can progress and dominate morbidity. Published survival, mortality, disability, and validated quality-of-life statistics are unavailable. Cosmetic distress, exertional dyspnea, recurrent surgery, and surveillance burden are plausible major impacts but are not quantified by disease-specific instruments. (pqac-00000011, pqac-00000012, pqac-00000013) | Documented patient ages extend to **84 years**, but this is not a life-expectancy estimate. (pqac-00000001) | Quality of life; chronic disease; exercise intolerance; facial appearance concern |
| Models | Human dermal fibroblasts and skin-equivalent systems reproduce abnormal tropoelastin deposition, ER stress, and elastic-fiber disorganization. A humanized transgenic mouse carrying an ADCL ELN frameshift incorporated mutant elastin into skin and lung fibers, developing adverse tissue effects and emphysema; mutant incorporation into aortic elastin was comparatively low, demonstrating tissue-specific assembly. (pqac-00000002, pqac-00000018) | Model findings include intracellular retention, apoptosis, emphysema, reduced lung stiffness, increased stretch, and increased TGF-beta signaling. (pqac-00000002) | Model organism: Mus musculus; transgenic model; humanized mouse; fibroblast culture; skin-equivalent model |
| Environmental and protective factors | ADCL1 is a monogenic disorder; no environmental cause or proven protective genetic, dietary, lifestyle, infectious, or occupational factor was identified. Avoidance of smoking and pulmonary irritants is clinically prudent for emphysema risk but is not proven to modify ADCL1 penetrance. | No ADCL1-specific gene–environment interaction statistics are available. | Tobacco-smoke exposure; air pollution exposure; environmental modifier |
| Evidence gaps | Major gaps include contemporary natural-history cohorts, 2023–2024 ADCL1-specific studies, validated prevalence, standardized surveillance intervals, prospective surgical outcomes, quality-of-life measures, prognostic biomarkers, modifier genes, epigenomics, single-cell or spatial profiling, and disease-modifying trials. | Available quantitative estimates rely heavily on a 20-person cohort and individual case reports. (pqac-00000001, pqac-00000010) | Natural history study; patient registry; multi-omics study; clinical trial |


*Table: Compact evidence table for ELN-related autosomal dominant cutis laxa 1, covering phenotype frequencies, variants, mechanism, diagnosis, surveillance, treatment, and evidence gaps. It explicitly distinguishes ADCL1 from predominantly recessive FBLN5-related cutis laxa.*