| Evidence domain | Human variant/model | Key phenotype or finding | Quantitative detail | Evidence type/strength | Source year and DOI |
|---|---|---|---|---|---|
| Foundational human genetics | **OSBPL2 c.141_142delTG, p.Arg50Alafs*103** (German DFNA67 family) | Childhood/adult-onset progressive bilateral sensorineural hearing loss; high frequencies affected first; intrafamilial variability; no vestibular symptoms reported | Onset reported between **10-30 years**; **5 family members** underwent cochlear implantation at **27-50 years** (pqac-00000004, pqac-00000005) | Human pedigree with cosegregation; strong disease-gene evidence, small family-based dataset | 2015, **10.1186/s13023-015-0238-5** |
| Foundational human genetics | **OSBPL2 c.158_159delAA, p.Gln53Argfs*100** (Mongolian family) | Late-onset hereditary deafness with delayed, progressive, bilateral symmetric sensorineural hearing loss | **6 generations**, **53 traceable individuals**, **19 affected**; onset **10-40 years**; severity **mild to severe**; absent in **201 unrelated controls** (pqac-00000007) | Human pedigree + WGS + Sanger cosegregation; strong family-level evidence | 2019, **10.1186/s12881-019-0781-3** |
| Discovery pedigree / recurrent exon-3 truncation cluster | **OSBPL2 c.153_154delCT / c.158_159delAA, p.Gln53Argfs*100** (Chinese/Korean reports; nomenclature differs by transcript/numbering) | Progressive nonsyndromic hearing loss; bilateral symmetric, down-sloping audiograms; postlingual onset | Chinese discovery family described as **7 generations**; Korean cohort estimated OSBPL2 variants in **2/202 (1.0%)** hearing-loss families (pqac-00000010, pqac-00000002, pqac-00000014) | Human pedigree and cohort evidence; strong for recurrent truncating mechanism, but transcript-numbering inconsistency should be noted | 2015, **10.1038/gim.2014.90**; 2022, **10.1080/15548627.2022.2040891** |
| Human genetics / additional recurrent truncation | **OSBPL2 c.180_181delCA, p.His60Glnfs*93** (Korean family YUHL457) | Symmetric progressive down-sloping sensorineural hearing loss with high-frequency-first pattern | Reported in one DFNA67 family; among Korean DFNA67 cases, onset generally **late teens to twenties**, with deterioration beginning by early second decade in family histories (pqac-00000002, pqac-00000013) | Human pedigree with recurrent frameshift finding; moderate-strong but still rare-family evidence | 2022, **10.1080/15548627.2022.2040891** |
| Core phenotype summary | Multiple truncating OSBPL2 families | DFNA67 is typically **postlingual, bilateral, symmetric, progressive SNHL** with **high-frequency/down-sloping** configuration and variable severity | Onset across reports spans about **5-40 years**; progression can reach **severe-profound deafness in adulthood** (pqac-00000003, pqac-00000004, pqac-00000005, pqac-00000013) | Aggregated across several pedigrees; moderate strength, limited by small total case count | 2015, **10.1186/s13023-015-0238-5**; 2022, **10.1080/15548627.2022.2040891** |
| Cochlear implantation outcomes | Affected DFNA67 individuals in YUHL3 and YUHL457 | Cochlear implantation can provide useful short-term speech outcomes in advanced disease | Implanted individuals included **YUHL3 II-5, III-4, III-13, IV-11** and **YUHL457 III-4, III-6**; sentence comprehension reportedly **80-100% at 3 months** post-implant (pqac-00000002) | Human intervention follow-up; clinically useful but very small uncontrolled series | 2022, **10.1080/15548627.2022.2040891** |
| Toxic protein / autophagy mechanism | Mutant OSBPL2 proteins **p.R50Afs*103, p.Q53Rfs*100, p.H60Qfs*93**; HsQ53R-TG mice | Frameshift proteins accumulate in cytoplasmic aggregates, bind autophagy proteins, disrupt endolysosomal homeostasis, and impair autophagic flux; supports **toxic proteinopathy** | Mutant-transgenic mice showed hearing loss, whereas **Osbpl2 knockout mice** and WT-OSBPL2 transgenic mice reportedly **did not** in this study (pqac-00000001, pqac-00000003, pqac-00000008) | Strong mechanistic in vitro + transgenic mouse evidence; **conflicts with knockout-hearing-loss findings from another group** | 2022, **10.1080/15548627.2022.2040891** |
| Cilia / PI(4,5)P2 / Shh mechanism | **Osbpl2-KO mice**, KO HEI-OC1 auditory cells | OSBPL2 localizes to kinocilia base/primary cilia; deficiency increases ciliary **PI(4,5)P2**, impairs ciliogenesis, and downregulates **SMO/GLI3** Shh signaling | KO mice developed **progressive hearing loss** with abnormal cochlear development and ciliary defects; PI(4,5)P2 excess partly rescued by **INPP5E** overexpression (pqac-00000000) | Strong experimental mouse/cell evidence; **mechanistically plausible but partially conflicts with “KO has no HL” report** | 2022, **10.1172/jci.insight.149626** |
| Large-animal model / diet interaction | **OSBPL2-disrupted Bama miniature pigs** | Progressive hearing loss with hair-cell degeneration, stereocilia abnormalities, apoptosis, plus hypercholesterolaemia | **High-fat diet aggravated** both hearing loss progression and hypercholesterolaemia; WT pigs showed minimal hearing effect from HFD in comparison (pqac-00000009, pqac-00000011) | Strong translational animal model; supports interaction with lipid metabolism, not yet proven in human DFNA67 | 2019, **10.1016/j.jgg.2019.06.006** |
| Broader ORP2 biology relevant to pathogenesis | Endogenous **ORP2/OSBPL2** in non-auditory systems | ORP2 is a **cholesterol/PI(4,5)P2 counter-transport** protein linked to plasma-membrane/endosomal cholesterol distribution, cell adhesion, and actin-associated signaling | Molecular role demonstrated in cell systems and knockout contexts outside DFNA67; provides biologic plausibility for cochlear lipid/cytoskeletal vulnerability (pqac-00000012) | Indirect mechanistic support; moderate relevance because not disease-specific auditory proof | 2021, **10.15252/embj.2020106871** |
| Five-patient proof-of-concept therapy | **Rapamycin 2 mg daily for 3 months** in **5 adults** with DFNA67 from YUHL3/YUHL457 | Partial improvement in hearing and tinnitus; proposed mechanism is reduction of mutant OSBPL2 accumulation and autophagy restoration | Approx. **5 dB improvement at 500 Hz**; improved DPOAE SNR in **1 patient**; tinnitus improved in **2 patients**; **no critical adverse events** reported (pqac-00000001) | Human proof-of-concept only; **very small, uncontrolled, short-term evidence** | 2022, **10.1080/15548627.2022.2040891** |
| Mouse therapeutic proof-of-concept | **HsQ53R-TG mice + rapamycin (P7-P15)** | Rapamycin reduced insoluble mutant protein deposition and partially rescued auditory function and cochlear pathology | Significant improvement in **ABR** and **DPOAE** thresholds at low frequencies; preservation of hair cells and SGNs (pqac-00000001) | Preclinical intervention evidence; moderate strength, supports mechanism-based repurposing | 2022, **10.1080/15548627.2022.2040891** |
| Current expert assessment (recent review) | DFNA67 within precision hearing-loss landscape | OSBPL2-related DFNA67 is cited as an example of **mechanism-based small-molecule therapy** in genetic hearing loss, but not standard of care | Review highlights rapamycin signal and frames DFNA67 as part of emerging genotype-guided therapy; no formal guideline or established trial program identified in the retrieved evidence (pqac-00000014) | Expert review/opinion; low-directness for efficacy, useful for context | 2024, **10.7874/jao.2024.00157** |


*Table: This table compiles the most decision-relevant human, mechanistic, animal-model, and early therapeutic evidence for OSBPL2-related DFNA67. It highlights recurrent truncating variants, the core progressive hearing-loss phenotype, and important areas where evidence is small or mechanistically conflicting.*